iii. Further Observations - Discontinuities Near the Hydrodynamic Threshold Velocity
The second very interesting trend that immediately leaps out in looking at these data is that nearly all of these types of bullets, simple gilding metal designs, bonded bullets and monolithics alike, exhibit highly erratic behavior as impact velocities approach and descend below ~2000 fps. This is due to the threshold pressure (or velocity, if you will) for bullet upset or expansion - the hydrodynamic threshold velocity. This upset velocity is the practical limit for their reliable use in hunting (jacketed bullets that do not expand are unpredictable and may produce very narrow wounds unless they yaw). It can be directly correlated with range.
While for some loads the rapidity of death may be improved by high velocity (from, say 2200 fps to 3000 fps), the practical lethality of modern weapons has not really increased significantly, merely their effective range. We're not speaking of whether or not these loads are lethal, merely how quickly. While contemporary magnums boast two or three times the kinetic energies of their forebears, it takes more work (energy) to expand modern bullets. This is work energy that is not being spent on the target. Additionally, at very high impact velocity (approaching or exceeding 3000 fps), most of that increase in kinetic energy is expended within a shallow penetration distance, so its not necessarily improving the wounding capability at depth in the target. The consequence of high velocity is the requirement for ever harder bullets, since nearly all hunting shots are still taken at less than 100 yards. So, the very thing that extends practical range (i.e., velocity) results in a countering design change that inhibits the full realization of that increase.
Modern bullets cease to function properly (expand) at velocities which were the muzzle velocities for the original jacketed bullets of a century ago. Modern bullets will function properly over a range of impact velocities from typically 2000 to 3200+ fps for premium bullets and from 2000 to 2800+ fps for conventional bullets. A few bullet designs, both premium and conventional, will expand well at impact velocities as low as 1800 fps in the case of spire points, or ~1600 fps for round noses (some, such as Remington RN Core-Lokts, work as low as 1400 fps). Bullets that work reliably at extended lower impact velocities tend to perform worse at the high end, and vice-versa; but not in all cases. Driven too fast, they erode and fragment into ruin with very shallow penetration; too slow and they do not expand at all, making a very deep (possibly more than 60 inches) but very narrow hole. Cast bullets with hardness and alloy carefully tailored to the load can produce very effective penetration and cavitation when launched with muzzle velocities of 1800 fps and less. Obviously, this discussion applies to rifle bullets; handgun bullets are designed to function at velocities of roughly 800 to 1400 fps. At rifle velocities, pistol bullets are generally destroyed at very shallow depth. The salient point here is that very lethal wounds can be created with rather modest amounts of kinetic energy, provided that the bullets conform to the needs of the impact conditions.
In the case of simple cup and core bullets, different jacket thicknesses must be used to match the bullet to the hunting conditions, or else the jacket can be tapered thin at the nose to expand at low velocity and made thick at the base to resist expansion at high velocity. For performance duplicating the old blackpowder and smokeless powder cartridges, it must be very thin indeed. Remember that these original bullets were jacketed with a thin coating of hard metal (originally cupronickel) to function as a patching material for the new "high velocity" (1800 to 2200 fps). Modern bullets are drawn or turned pure copper or copper alloy (e.g., 95 Cu - 5 Zn gilding metal) jackets with lead cores inserted. Monolithic bullets require sophisticated forming and heat treatment to control the tendency to work hardening of the copper. The shank needs to be harder to minimize fouling, but the ogive must be soft to permit expansion and yet still resist petal shearing at high velocity. In principle, core bonding should make it easier to design a bullet to expand reliably at impact velocities below 1800 fps while still performing well at higher velocity (because the bonding will prevent serious core erosion and weight loss), but in practice bonded bullets tend to be designed to be very tough and in consequence often are less inclined to expand than conventional bullets. This is the ironic aspect of some premium bullet designs, in that they provide a reduced effective range.
It is noteworthy that the commercial loadings will perform at up to 400 fps lower impact velocity than some of the reloading brand bullets, which translates into extended effective lethal range. Here too, we see a trend which explains the effectiveness of many an "obsolete" cartridge whose kinetic energy figures simply pale in comparison to many high powered rounds of today. With a bullet matched in its metallurgical characteristics to the velocity of the rifle (or handgun), performance equivalent or even surpassing that of chamberings of greater theoretical power could be achieved. This is because, as alluded to earlier, an instantaneous kill through massive trauma is not more effective than a kill which drops the animal inside 50 to 100 yds; a level of lethality which can be achieved rather easily with careful selection of jacket design and core alloy (for those with the skill, such as Veral Smith, this can be done with impact velocities under 2000 fps using cast and heat treated bullets).
The X-Bullet is touted as a phenomenal slayer of game, yet it is clear from the penetration (fully 33% greater than most conventional designs) and the narrow profile of recovered bullets that the wound channel is of more modest dimensions than that produced by many bullets (see actual test results hereafter). Similar observations have been made of the long heavy bullets used in low-velocity loadings of the .303 Lee-Metford/Enfield (aka .303 British), .30-40 Krag-Jorgensen, 6.5 x 54 mm (aka .256) Mannlicher-Schoenauer and 7 x 57 mm Mauser from the turn of the century. These cartridges, considered underpowered by contemporary standards, were considered phenomenal slayers of very large game, including the largest species of African antelope, elk, moose, and even grizzlies. [This is a premise that I intend to verify or refute by a direct testing of vintage bullets - stay tuned.]
As a parting comment on this subject, consider the following excerpt from an article written by (then) Major Charles Askins Jr. of the US Border Patrol that appeared in the November 1930 issue of The American Rifleman:
- The modern tendency in cartridge building is to leave the bullets as they are and to speed them up. The bullet that was designed and well designed, for a velocity of 2300 feet [sic] is speeded up to the velocity of 2800 feet [sic], with no change in the bullet jacket. I question the wisdom of this, and question whether the high velocity bullet is going to prove a better killer than the same missile at lower velocity. In like manner - still worse and more of it - bullet speed has been obtained by lightening the missile. This has been done with the .30-06, the 7mm, the .256, and the .250, and the results are in grave doubt where animals are to be shot above a certain size. In very large game shooting I'd far rather trust the 220 grain in .30-06, the 175 grain in 7mm, the 160 grain in .256, the 117 grain in .250, the 350 grain in .375 to any of the lighter missiles that are made for these calibers. The thing lies partly in weight of lead, but still more in keeping the speed of the bullet down to its working velocity.
Some caveats are in order when reviewing Sciuchetti's data and making assessments. These data represent only the performance of 180 gr .308 caliber bullets. Bullets of the same caliber, but a different weight will differ in performance for any given design. Sciuchetti found that penetration of .308 caliber Speer Grand Slam bullets (selected for their similarity of design) gave penetrations of 13 to 13.5 in (150 gr, 2910 fps), 16 to 17.5 in (165 gr, 2855 fps), 14.5 to 19 in (180 gr, 2746 fps), and 16.5 to 18.5 in (200 gr, 2620 fps). It must be admitted that these figures also reflect the influence of differences in impact velocity, though as we have already seen penetration is a weak function of velocity for bullets of this construction and the narrow region being examined. In general, with the exception of the lightest weight bullet, these all performed very similarly with possibly a statistically insignificant advantage given for increasing sectional density between 165 grs and 200 grs (average: 13.25, 16.75, 16.75 and 17.5 inches).
2. Minimum Wound Dimensions
The following plot provides a point of reference for the wetpack test data to be presented hereafter. An attempt was made to depict the shape of the wound track that would be produced in real terms (in a wetpack). The larger portion of the cavity, in length and diameter, describes the lesion that would deliver a minimum lethal wound if it were in the vital region (i.e., neglecting penetration of muscle and bone). The smaller diameter portion of the lesion corresponds to a typical penetration after velocity attenuation and represents the depth of penetration that would be minimally lethal at that diameter. It also assumes a penetration sufficient to fully penetrate the thorax on a crosswise shot that is stopped just under the hide on the far side. In other words, a bullet satisfying the requirements of the first portion of the wound track would also create the latter, but have only just enough energy to penetrate to the skin.
One can readily see that quite a lot of penetration is indicated for the largest species of game. A typical male giraffe has a mass of about 1350 kg, a large buffalo about 900 kg, a moose between 500 and 700 kg, an elk or grizzly around 350 kg, a kudu roughly 250 kg. Most game animals are less than 350 kg and so rather modest penetration is acceptable. The full depth of penetration isn't absolutely essential, its the first portion of the wound that is critical, but lacking the latter penetration raises some doubt as to whether the primary killing portion of the wound will reliably occur in vital tissues and whether the bullet / load has adequate capability for the task under all reasonable shotlines or rather constitutes something of a trick shot proposition. Of course, the dimensions are only approximate, but are derived from the table of minimum wounds in Part II.a. The Mechanics of Lethal Wounding.
3. Medium-Bore Bullets
I will betray a bias of mine for medium bore rifles and introduce the next discussion - somewhat out of the expected sequence of things - with these calibers. In truth, this is where I began my investigations, so here I will begin the tale. I define medium bore calibers, rather arbitrarily, as those having a maximum bullet weight of greater than 200 grains and less than 400 grains; so its .308 to .375 caliber.
Sciuchetti confined his exhaustive study to a single caliber and bullet weight. Comparable variation to that observed by Sciuchetti are the differences that will be encountered when comparing loads differing caliber, sectional density and/or design. Consider the following selection of data (see Medium Bore Wetpack Test Data) obtained from other published sources, also using saturated phonebooks as a test medium.
Bullets of medium and large caliber often have much stronger jackets than similar designs of lesser caliber. Moreover, the .338 caliber bullets may be inherently stronger than .358 caliber bullets of apparently similar construction because .338 caliber cartridges are almost always magnums with very high muzzle velocities, while the others may include chamberings with relatively low velocities (i.e., the .358 Winchester and .35 Whelen). Nevertheless, I had to exclude two reported tests of .340 Weatherby Magnum loads by Bob Hagel ("8 mm Remington Magnum", Big Bore Rifles and Cartridges, Wolfe Publishing, Inc., 1991, pp. 23 - 27.) which claimed penetrations of 28 and 30 inches respectively for the 210 grain and 250 grain Nosler Partitions. I cannot account for the large discrepancy in these alleged penetrations vis-a-vis the performance of comparable bullets in the .338-06, .338 Winchester Magnum, .340 Weatherby Magnum and .35 Whelen as tested by myself and Finn Aagaard (it could be a typo; the actual values may have been 18 and 20 inches). Various writers have also alleged that the .338 bores will out-penetrate the .375 Holland and Holland; an assertion which I believe is based upon the compared sectional densities of .338-250 grain and .375-300 grain bullets, not actual tests. You will note that the .375 caliber 300 grain Partition meets or exceeds the penetration of .338 and .358 bullets weighing 250 grains. A .375 Holland and Holland 300 gr solid is included in the table for comparison.
Reported Wetpack Test Data for Medium-Bore Rifle Bullets
| Caliber / Cartridge |
Bullet Type / Mass |
Impact Velocity |
Expanded Diameter |
Depth of Penetration |
Retained Weight |
Note |
| .308 Winchester |
165 gr Nosler Ballistic Tip |
2470 fps |
0.504 in |
14.5 in |
126 gr / 77 % |
7 |
|
165 gr Nosler Partition |
2450 fps |
0.448 in |
17.0 in |
128 gr / 77 % |
7 |
| .30-06 Springfield |
150 gr Barnes X-Bullet |
2850 fps |
0.532 in |
16.5 in |
133 gr / 89 % |
4 |
|
150 gr Winchester Fail-Safe |
2946 fps |
0.401 in |
19.7 in |
121 gr / 80 % |
6 |
|
165 gr Barnes X-Bullet |
2790 fps |
0.480 in |
20.9 in |
134 gr / 81 % |
4 |
|
165 gr Hornady Interlock |
2790 fps |
0.532 in |
16.1 in |
99 gr / 60 % |
4 |
|
165 gr Nosler Partition |
2790 fps |
0.590 in |
18.9 in |
116 gr / 70 % |
4 |
|
165 gr Sierra Game King |
2820 fps |
0.503 in |
9.1 in |
101 gr / 61 % |
6 |
|
165 gr Speer Grand Slam |
2780 fps |
0.438 in |
12.0 in |
112 gr / 68 % |
6 |
|
165 gr Swift A-Frame |
2850 fps |
0.670 in |
19.3 in |
156 gr / 95 % |
4 |
|
165 gr Winchester FailSafe |
2790 fps |
0.430 in |
26.0 in |
132 gr / 80 % |
4 |
|
180 gr Federal Fusion |
2745 fps |
0.693 in |
12.6 in |
134 gr / 74 % |
6 |
|
180 gr Hornady Interlock |
2750 fps |
0.550 in |
15.7 in |
103 gr / 57 % |
4 |
|
180 gr Nosler Accubond |
2765 fps |
0.582 in |
13.0 in |
127 gr / 71 % |
6 |
|
180 gr Nosler Partition |
2680 fps |
0.480 in |
16.0 in |
122 gr / 68 % |
2 |
|
180 gr Remington Core-Lokt |
2650 fps |
0.540 in |
12.6 in |
82 gr / 46 % |
2 |
|
180 gr Remington Core-Lokt |
2640 fps |
0.690 in |
12.5 in |
129 gr / 72 % |
5 |
|
180 gr Remington Core-Lokt |
2642 fps |
0.525 in |
12.0 in |
132 gr / 73 % |
6 |
|
180 gr Swift A-Frame |
2750 fps |
0.590 in |
21.7 in |
177 gr / 98 % |
4 |
|
180 gr Winchester Silvertip |
2766 fps |
0.665 in |
10.9 in |
135 gr / 75 % |
6 |
|
180 gr Woodleigh Weld-Core |
2750 fps |
0.870 in |
15.7 in |
165 gr / 92 % |
4 |
|
200 gr x 0.025 Hawk RT |
xxxx fps |
0.595 in |
10.2 in |
129 gr / 65 % |
6 |
|
200 gr North Fork Technologies |
2550 fps |
0.652 in |
15.7 in |
199 gr / 99 % |
6 |
|
200 gr Swift A-Frame |
2626 fps |
0.570 in |
18.5 in |
186 gr / 93 % |
2 |
|
220 gr x 0.035 Hawk RT |
xxxx fps |
0.685 in |
11.6 in |
175 gr / 80 % |
6 |
|
220 gr Nosler Partition |
2519 fps |
0.510 in |
19.0 in |
145 gr / 66 % |
2 |
|
220 gr Nosler Partition |
2470 fps |
0.460 in |
20.5 in |
153 gr / 70 % |
6 |
|
220 gr Sierra Pro-Hunter |
2525 fps |
0.470 in |
18.1 in |
108 gr / 49 % |
4 |
|
220 gr Winchester Silvertip |
2410 fps |
0.638 in |
10.9 in |
158 gr / 72 % |
6 |
|
220 gr Woodleigh Weldcore RN |
xxxx fps |
0.702 in |
11.7 in |
199 gr / 91 % |
6 |
|
250 gr Barnes Original |
2340 fps |
0.685 in |
11.5 in |
165 gr / 66 % |
6 |
| .300 Winchester Magnum |
165 gr Nosler Ballistic Tip |
3143 fps |
0.448 in |
12.7 in |
92 gr / 56 % |
7 |
|
165 gr Nosler Partition |
3111 fps |
0.476 in |
16.5 in |
110 gr / 67 % |
7 |
|
180 gr Nosler Ballistic Tip |
2944 fps |
0.456 in |
11.8 in |
91 gr / 51 % |
6 |
|
180 gr North Fork Technologies |
2642 fps |
0.600 in |
15.4 in |
175 gr / 97 % |
6 |
|
200 gr Barnes X-Bullet |
2730 fps |
0.584 in |
19.3 in |
190 gr / 95 % |
6 |
|
200 gr Swift A-Frame |
2825 fps |
0.636 in |
17.1 in |
193 gr / 96 % |
6 |
|
220 gr Hornady Interlock RN |
2370 fps |
0.514 in |
13.9 in |
121 gr / 55 % |
6 |
| 8 mm Remington Magnum |
150 gr Sierra Pro-Hunter |
3150 fps |
0.800 in |
12 in |
49 gr / 32 % |
1 |
|
175 gr Sierra Pro-Hunter |
3025+ fps |
0.675 in |
16 in |
80 gr / 46 % |
1 |
|
185 gr Remington Core-Lokt |
2875 fps |
0.720 in |
12 in |
78 gr / 42 % |
1 |
|
220 gr Remington Core-Lokt |
2750+ fps |
0.810 in |
22 in |
127 gr / 58 % |
1 |
|
220 gr Hornady Interlock |
2800+ fps |
0.710 in |
23 in |
114 gr / 52 % |
1 |
| .338-06 |
230 gr Winchester Fail-Safe |
2509 fps |
0.530 in |
21.5 in |
230 gr / 100 % |
2 |
|
250 gr Nosler Partition |
2407 fps |
0.600 in |
18.3 in |
195 gr / 78 % |
2 |
| .338 Winchester Magnum |
250 gr Nosler Partition |
2637 fps |
0.630 in |
18.5 in |
194 gr / 78 % |
2 |
|
250 gr Nosler Partition |
2550 fps |
0.660 in |
19.5 in |
200 gr / 80 % |
5 |
| .340 Weatherby Magnum |
200 gr Nosler Ballistic Tip |
3025 fps |
0.590 in |
17.3 in |
121 gr / 61 % |
6 |
|
210 gr Nosler Partition |
3050 fps |
0.639 in |
16.3 in |
159 gr / 76 % |
6 |
|
210 gr Nosler Partition |
2840 fps |
0.633 in |
16.2 in |
167 gr / 80 % |
6 |
|
210 gr Barnes X-Bullet |
2850 fps |
0.413 in |
23.6 in |
163 gr / 77 % |
6 |
|
225 gr North Fork Technologies |
xxxx fps |
0.649 in |
19.6 in |
190 gr / 84 % |
6 |
|
225 gr Nosler Accubond |
xxxx fps |
0.566 in |
15.2 in |
132 gr / 59 % |
6 |
|
225 gr Speer Trophy-Bonded Bear Claw |
2900 fps |
0.775 in |
17.3 in |
191 gr / 85 % |
6 |
|
225 gr Speer Trophy-Bonded Bear Claw |
2900 fps |
0.657 in |
18.7 in |
200 gr / 89 % |
6 |
|
240 gr North Fork Technologies |
xxxx fps |
0.662 in |
18.3 in |
232 gr / 97 % |
6 |
|
250 gr Nosler Partition |
2600 fps |
0.625 in |
18.4 in |
197 gr / 79 % |
6 |
|
275 gr Swift A-Frame |
2600 fps |
0.668 in |
21.7 in |
263 gr / 96 % |
6 |
| .348 Winchester |
200 gr Hornady Interlock FP |
2330 fps |
0.653 in |
11.9 in |
178 gr / 89 % |
6 |
|
200 gr Winchester Silvertip |
2400 fps |
0.628 in |
10.6 in |
138 gr / 69 % |
6 |
|
220 gr Barnes Original |
2275 fps |
0.673 in |
13.1 in |
200 gr / 91 % |
6 |
|
220 gr Barnes X-Bullet |
2275 fps |
0.646 in |
17.9 in |
219 gr / 100 % |
6 |
|
230 gr North Fork Technologies |
2090 fps |
0.621 in |
14.8 in |
227 gr / 99 % |
6 |
|
250 gr Barnes Original |
2150 fps |
0.738 in |
12.1 in |
221 gr / 88 % |
6 |
| .35 Whelen |
180 gr Speer Hot-Cor FN |
2730 fps |
0.630 in |
13.5 in |
124 gr / 69 % |
5 |
|
200 gr Sierra RN |
2623 fps |
0.760 in |
11.0 in |
115 gr / 58 % |
5 |
|
200 gr Remington Pointed Core-Lokt |
2600 fps |
0.670 in |
13.5 in |
149 gr / 75 % |
5 |
|
220 gr Speer Hot-Cor FN |
2609 fps |
0.640 in |
15.0 in |
157 gr / 71 % |
5 |
|
225 gr Swift A-Frame |
2550 fps |
0.720 in |
15.5 in |
213 gr / 95 % |
5 |
|
240 gr Trophy-Bonded Bear Claw |
2486 fps |
0.730 in |
16.5 in |
227 gr / 95 % |
5 |
|
250 gr Remington Core-Lokt RN |
2271 fps |
0.630 in |
16.5 in |
204 gr / 82 % |
5 |
|
250 gr Hornady Interlock RN |
2180 fps |
0.650 in |
17.5 in |
203 gr / 81 % |
5 |
|
250 gr Hornady Interlock RN |
2437 fps |
0.600 in |
17.0 in |
162 gr / 65 % |
5 |
|
250 gr Speer Hot-Cor Spitzer |
2172 fps |
0.590 in |
20.5 in |
208 gr / 83 % |
5 |
|
250 gr Speer Hot-Cor Spitzer |
2449 fps |
0.590 in |
18.5 in |
181 gr / 73 % |
5 |
|
250 gr Swift A-Frame |
2150 fps |
0.740 in |
18.0 in |
247 gr / 99 % |
5 |
|
250 gr Swift A-Frame |
2470 fps |
0.720 in |
17.0 in |
239 gr / 96 % |
5 |
|
250 gr Nosler Partition |
2504 fps |
0.650 in |
18.3 in |
213 gr / 85 % |
2 |
|
270 gr Trophy-Bonded Bear Claw |
2372 fps |
0.780 in |
18.0 in |
264 gr / 98 % |
5 |
|
275 gr Barnes Original |
2322 fps |
0.790 in |
17.5 in |
259 gr / 94 % |
5 |
|
280 gr Swift A-Frame |
2324 fps |
0.650 in |
19.0 in |
262 gr / 94 % |
2 |
|
300 gr Barnes Original RN |
2244 fps |
0.830 in |
17.0 in |
283 gr / 94 % |
5 |
| 9.3 x 62 mm Mauser |
258 gr RWS H-Mantel |
2393 fps |
|
24+ in |
|
2 |
|
270 gr Speer Soft Point |
2482 fps |
0.550 in |
17.0 in |
161 gr / 60 % |
2 |
|
286 gr RWS RN Soft Point |
2375 fps |
0.630 in |
11.0 in |
126 gr / 44 % |
2 |
|
286 gr Nosler Partition |
2370 fps |
0.620 in |
19.0 in |
227 gr / 79 % |
2 |
|
286 gr Barnes X-Bullet |
2386 fps |
0.630 in |
19.0 in |
286 gr / 100 % |
2 |
|
300 gr Swift A-Frame |
2308 fps |
0.660 in |
19.3 in |
276 gr / 92 % |
2 |
| .375 Hawk / Scovill |
250 gr North Fork Technologies |
2605 fps |
0.714 in |
15.2 in |
243 gr / 97 % |
6 |
|
270 gr North Fork Technologies |
2525 fps |
0.718 in |
15.3 in |
247 gr / 91 % |
6 |
| .375 Holland & Holland Magnum |
270 gr Winchester Fail-Safe |
2619 fps |
|
24+ in |
|
2 |
|
300 gr Nosler Partition |
2481 fps |
0.680 in |
19.5 in |
253 gr / 84 % |
2 |
|
300 gr Hornady FMJ RN |
2550 fps |
0.375 in |
40 in |
|
3 |
-
1 -- Bob Hagel, "8 mm Remington Magnum", Big Bore Rifles and Cartridges, Wolfe Publishing, Inc., 1991, pp. 23 - 27.
2 -- Finn Aagaard, "9.3 x 62 mm Mauser", Handloader, Wolfe Publishing, Inc., June-July, No. 199, 1999, pp. 32 - 37, 78.
3 -- Jim Gosnell, "Legendary Linebaugh Big-Bores", High-Power Handguns, Petersen Publishing, Inc., 1995, pg. 37.
4 -- Independent testing by Øyvind Hannisdal
5 -- Finn Aagaard, "The .35 Whelen", American Rifleman, National Rifle Association, April, 1988, pp. 43 - 45, 82 - 83, 86, 88.
6 -- Independent testing by the author
7 -- Rick Jamison, Nosler Reloading Guide Number 4, pp. 55 - 56.
i. .308 Caliber
Gary Sciuchetti performed his study on .308 caliber, and its the most popular caliber in America, so perhaps this is the best place to start a discussion of my own testing and assessments. Its a bit redundant, but the following is a redacted version of the preceding table, showing only my own testing results. A few of these need the velocities chronographed, but for the present assume that they are within about 200 fps of nominal muzzle velocities.
Wetpack Penetration Data for .308 Caliber Bullets
| Caliber / Cartridge |
Bullet Type / Mass |
Impact Velocity |
Expanded Diameter |
Depth of Penetration |
Retained Weight |
| .30-06 Springfield |
150 gr Winchester Fail-Safe |
2946 fps |
0.401 in |
19.7 in |
121 gr / 80 % |
|
165 gr Sierra Game King |
2820 fps |
0.503 in |
9.1 in |
101 gr / 61 % |
|
165 gr Speer Grand Slam |
2780 fps |
0.438 in |
12.0 in |
112 gr / 68 % |
|
180 gr Federal Fusion |
2745 fps |
0.693 in |
12.6 in |
134 gr / 74 % |
|
180 gr Nosler Accubond |
2765 fps |
0.582 in |
13.0 in |
127 gr / 71 % |
|
180 gr Remington Core-Lokt |
2642 fps |
0.525 in |
12.0 in |
132 gr / 73 % |
|
180 gr Winchester Silvertip |
2766 fps |
0.665 in |
10.9 in |
135 gr / 75 % |
|
200 gr x 0.025 Hawk RT |
xxxx fps |
0.595 in |
10.2 in |
129 gr / 65 % |
|
200 gr North Fork Technologies |
2550 fps |
0.652 in |
15.7 in |
199 gr / 99 % |
|
220 gr x 0.035 Hawk RT |
xxxx fps |
0.685 in |
11.6 in |
175 gr / 80 % |
|
220 gr Nosler Partition |
2470 fps |
0.460 in |
20.5 in |
153 gr / 70 % |
|
220 gr Winchester Silvertip |
2410 fps |
0.638 in |
10.9 in |
158 gr / 72 % |
|
220 gr Woodleigh Weldcore RN |
xxxx fps |
0.702 in |
11.7 in |
199 gr / 91 % |
|
250 gr Barnes Original |
2340 fps |
0.685 in |
11.5 in |
165 gr / 66 % |
| .300 Winchester Magnum |
180 gr Nosler Ballistic Tip |
2944 fps |
0.456 in |
11.8 in |
91 gr / 51 % |
|
180 gr North Fork Technologies |
2642 fps |
0.600 in |
15.4 in |
175 gr / 97 % |
|
200 gr Barnes X-Bullet |
2730 fps |
0.584 in |
19.3 in |
190 gr / 95 % |
|
200 gr Swift A-Frame |
2825 fps |
0.636 in |
17.1 in |
193 gr / 96 % |
|
220 gr Hornady Interlock RN |
2370 fps |
0.514 in |
13.9 in |
121 gr / 55 % |
The following illustrations of "wound" tracks in saturated phonebook wetpacks were made from measurements obtained in tests that I performed which are described in the foregoing table and hereafter. The radial (vertical) and the axial (horizontal) dimensions are drawn to scale. It is worth reiterating that actual wounds in game animals tend to be both larger in diameter and deeper than in wetpacks, depending on the bone structures and tissues which are struck. The wound track plots are shown in descending sequence from heaviest bullet weights to lightest.
I concentrated on heavy bullets in the .308 caliber mainly because I had loads for my brother's Model 70 in .300 Winchester Magnum and because I am looking for good traditional loads for my Browning Model 1895. Several interesting things are evident. For one thing, most of the .308 caliber bullets that were tested achieved only about 10 to 12 inches of penetration - a lot less than I expected. This includes some high dollar custom bullets and commercial "controlled expansion" types. That latter class generally produces larger diameter holes over the latter portion of their penetration, but they all deliver similar penetration. Only the Winchester Fail-Safe, Barnes X, North Fork, Swift A-Frame and Nosler Partition really step out penetration wise, and they all deliver substantially more.
Compare the Remington .308-180 grain Core-Lokt factory loads with the 180 grain North Fork Technologies bonded core bullet at the same velocity. The latter doesn't expend as much of its energy at very shallow depths and produces significantly more penetration (incidentally, the North Fork cavity profile looks a bit truncated in maximum expansion and I suspect that I recorded a couple of data points incorrectly). But then compare the factory loaded Core-Lokt to the .308-165 grain Speer Gram Slam or the new .308-180 grain Federal Fusion bonded bullet (or the 180 grain Nosler Ballistic Tip, for that matter). There is not much difference. The Grand Slam can be counted on to deliver a bit larger diameter wound beyond the initial expansion region. The Fusion produces a huge expansion cavity and retains its weight well, but the tail end of the cavity is not large and the penetration is not impressive. One of the lessons here is that it is very difficult to design and manufacture a bullet which produces a large diameter cavity, yet very deep penetration across a broad range of expected impact velocities. The custom bullets which can achieve this are definitely worth the extra money.
Observe the difference in the wound tracks produced by a .308-200 grain X-Bullet (original flat base design) in which only one petal was lost late in the penetration and the ~200 fps higher velocity .308-150 grain Winchester Fail-Safe bullet which lost all its petals very quickly. My brother and I used the first load in Namibia and you can see why it was so effective. The Fail-Safe bullet will probably perform much the same as the X-Bullet at lower impact velocities. But while the cavitation is not remarkable (though quite adequate for smaller species of big game), the penetration of the 150 grain Fail-Safe is extreme, especially for so light a bullet.
The conventional .308 caliber 220 grain designs do not appear to offer more modest cavitation yielding meaningful gains in penetration, as conventional wisdom about sectional density has long held. The Hornady penetrates deeper than the Winchester Silvertip, yet neither drives as far as the 180 grain Winchester Fail-Safe, 180 or 200 grain North Forks, 200 grain Swift A-Frame, the 200 grain X-Bullet, or 220 gr Nosler Partition. In fact, most of the 220 grainers don't even equal the 180 grain Core-Lokt in penetration depth. Both the .308 caliber 180 grain and 220 grain Winchester Silvertips are classed as "CXP3", described as being "Ideal for game such as elk, moose and brown bear" in Winchester product literature and on the cartridge carton (emphasis added). Now, I don't want to get into a legal battle with a major ammunition manufacturer over semantics (or anything else), but I don't see much distinction between the general run of ordinary bullets and the "controlled expansion" design in terms of penetration. Were I hunting brown bear (as opposed to elk or moose), my notion of the ideal bullet would involve a good deal more penetration. That's my opinion. The Silvertip is a fine hunting bullet. That is also my opinion. Both retained over 70% of their weight and expanded nicely. They compare favorably to the Hawks, the Woodleigh and the massive 250 gr Barnes Original, all of which deliver the goods. From what we know of field performance, it would appear that a bullet that delivers 9 to 12 inches of penetration in a wetpack with at least a 0.60 inch (15 mm) diameter hole is sufficient to dispatch most big game. These are clearly well beyond that minimum level of performance.

Legend - (L-R) An array of .308 caliber bullets: (1,2) 180 gr Winchester Silvertip (loaded cartridge and recovered), (3,4) 200 gr Hawk (0.025 inch jacket) Round Tip (unfired and recovered), (5,6) 220 gr Hawk (0.035 inch jacket) Round Tip (unfired and recovered), (7,8) 220 gr Woodleigh Weldcore (unfired and recovered)
ii. .338 Caliber
Now we come to my favorite caliber, and you can immediately begin to see the beneficial effects of bullet weight and structural integrity on performance. In contrast with the .308 caliber, none of these achieved less than 350 mm (14 inches) in penetration. The table of wetpack test data below corresponds with the figures that follow, illustrating the measured wound tracks in the wetpack.
Wetpack Penetration Data for .338 Caliber Bullets
| Caliber / Cartridge |
Bullet Type / Mass |
Impact Velocity |
Expanded Diameter |
Depth of Penetration |
Retained Weight |
| .340 Weatherby Magnum |
200 gr Nosler Ballistic Tip |
3025 fps |
0.590 in |
17.3 in |
121 gr / 61 % |
|
210 gr Nosler Partition |
3050 fps |
0.639 in |
16.3 in |
159 gr / 76 % |
|
210 gr Nosler Partition |
2840 fps |
0.633 in |
16.2 in |
167 gr / 80 % |
|
210 gr Barnes X-Bullet |
2850 fps |
0.413 in |
23.6 in |
163 gr / 77 % |
|
225 gr North Fork Technologies |
xxxx fps |
0.649 in |
19.6 in |
190 gr / 84 % |
|
225 gr Nosler Accubond |
xxxx fps |
0.566 in |
15.2 in |
132 gr / 59 % |
|
225 gr Speer Trophy-Bonded Bear Claw |
2900 fps |
0.775 in |
17.3 in |
191 gr / 85 % |
|
225 gr Speer Trophy-Bonded Bear Claw |
2900 fps |
0.657 in |
18.7 in |
200 gr / 89 % |
|
240 gr North Fork Technologies |
xxxx fps |
0.662 in |
18.3 in |
232 gr / 97 % |
|
250 gr Nosler Partition |
2600 fps |
0.625 in |
18.4 in |
197 gr / 79 % |
|
275 gr Swift A-Frame |
2600 fps |
0.668 in |
21.7 in |
263 gr / 96 % |
The most obvious and striking difference (for me) between conventional wisdom and real world performance is that the .338-200 grain Nosler Ballistic Tip actually outpenetrated the highly regarded .338-210 gr Nolser Partition, and made a respectable but not excessive cavity (although this was one of my very earliest tests and that cavity is anomalous - I intend to repeat that some day). Mind you, this is at an impact velocity not far off the highest muzzle velocity possible; it will only improve with moderated velocity downrange. Many report that the larger caliber Ballistic Tips are serious big game bullets in a different class than their small caliber cousins. I have also found that the larger caliber Partitions produce larger expanded diameters than the smaller bores for the same reason: heavier jacket thicknesses.
These tests also document the behavior exhibited by the Barnes X-Bullet and Winchester Fail Safe designs in Sciuchetti's testing in which increased penetration was observed at the highest velocities because the petals sheared off leaving only a blunt cylinder. In my testing with a 210 grain XBT load in .340 Weatherby it did this at a velocity of 2850 fps, leaving a square-ended blunt cylinder. This petal shearing seems to occur at impact velocities above 2600 to 2700 fps or so. Although the forward portion of the Nosler Partition bullet is also quickly ablated at similar velocities, these bullets (in the medium bores) tend to retain a broad, flat expanded diameter and to penetrate well despite the lost mass, in contrast with a "de-flowered" X-Bullet which penetrates very deeply but leaves a rather narrow wound over the last third of the distance (however, considering that this narrowing behavior occurs beyond the depth at which most good bullets stop and that the broad flat end cavitates more efficiently than a smooth "mushroom", it may not be a detriment). In a smaller caliber the narrow wound might be less than desired but in a medium or large bore (especially) it may make the most efficient use of the kinetic energy of a bullet. I have not yet tested one of the .338 caliber 225 or 250 grain X-Bullets, but its is possible that these will create a cavernous and very deep wound path similar to that produced by the .308-200 gr design. It is also probable, as previously mentioned, that below the petal shedding threshold of ~2700 fps, this 210 grain XBT bullet (now replaced by the TSX design) will make a larger diameter wound track, while maintaining its high penetration. It is a test I need to conduct in the future. Its also possible, although I have seen no evidence of this, that Barnes has solved the heat treatment or strain hardening problem that leads to the petal shearing at high velocity.
The lower velocity (2840 fps) 210 grain Partition and the 250 grain Partition were loaded to impact with identical kinetic energies (3750 ft-lbs). The heavier bullet penetrates 14% deeper while making a slightly larger cavity. The .338-225 gr Trophy-Bonded Bear Claw bullet creates a larger diameter cavity than any other design tested thus far, admittedly at a high impact velocity (2900 fps). It seems to exhibit a singularly violent expansion, yet holds together well and penetrates deeply. Note that the .338-225 grain North Fork beats it for penetration depth, but creates a much narrower expansion cavity. This bullet and the Swift A-Frame design of equal weight should create nearly identical holes at equal impact velocities. Most Swift A-Frames that I have tested have leaned more in the direction of true expansion control and give deeper penetration. This makes sense for Swift because they have the Scirocco for more expansive performance. North Forks can be of either persuasion (controlled expansion or controlled retained weight with large expansion). These three bullets are probably among the most lethal hunting bullets made, but that can be equally said of several other designs, including the Swift Scirocco, Barnes TSX and Nosler Accubond.
Finally, among the conventional bullets the 250 grain Sierra Game King compares very favorably, at this velocity, with the 250 grain Nosler Partition and 240 grain North Fork - no mean feat. It has an extra heavy double tapered jacket and very hard antimony alloy core, so I don't know how readily it will expand at lower velocities. Its a test I need to try. The massive 275 grain Speer Hot-Cor semi-spitzer (now discontinued), on the other hand, would probably only improve with reduced velocity; although its not a bad performer at what is literally muzzle velocity from a .340 Weatherby. All of which simply goes to show that, with some effort, old-school conventional bullets still have their place and can compete head to head with the custom and premium bullets.

Legend - (L-R) An array of .338 caliber bullets: (1) 200 gr Nosler Ballistic Tip, (2) 210 gr Nosler Partition, (3) 210 gr Barnes X-Bullet, (4) 250 gr Nosler Partition, (5) 275 gr Swift A-Frame

Legend - (L-R) .338 caliber bullets tested in the foregoing figure: (1) 200 gr Nosler Ballistic Tip, (2) 210 gr Barnes X-Bullet, (3) 210 gr Nosler Partition, (4) 225 gr Trophy Bonded Bear Claw, (5) 250 gr Nosler Partition, (6) 275 gr Swift A-Frame
iii. A Study of Sectional Density
The following parametric study of the effect of sectional density on bullet performance should largely lay to rest the off-quoted generalization that heavy for caliber bullets or bullets of some particular sectional density penetrate deeper and retain more mass. All the bullets used were of conventional construction, meaning lead alloy bullets in drawn copper alloy jackets; no bonded cores, partitions or other special constructions. All were loaded to a muzzle velocity of 2750 to 2800 fps, in order to eliminate the variable of velocity.
A Study of Sectional Density: Medium-Bore
| Caliber / Cartridge |
Bullet Type / Mass |
Sectional Density |
Impact Velocity |
Expanded Diameter |
Depth of Penetration |
Retained Weight |
| .340 Weatherby Magnum |
200 gr Speer SP |
0.250 |
2800 fps |
0.561 in |
17.5 in |
132 gr / 66 % |
|
225 gr Speer BTSP |
0.281 |
2800 fps |
0.553 in |
14.3 in |
134 gr / 59 % |
|
250 gr Sierra Game King |
0.313 |
2800 fps |
0.610 in |
15.8 in |
150 gr / 60 % |
|
275 gr Speer Semi-Spitzer |
0.344 |
2750 fps |
0.505 in |
17.2 in |
115 gr / 42 % |
In a stunning repudiation of conventional wisdom, the lightest bullet tested (200 grain Speer Hot-Cor) penetrated to the greatest depth and the heaviest bullet (275 grain Speer Hot-Cor) lost the most mass both in absolute terms and on a percentage basis. To be fair, apart from the 200 grain Speer, the bullets performed as one might expect (see the Sectional Density Study Figure below). Still the point I raise remains valid: generalizations are simply that; specific bullets may not behave as expected.
The best looking recovered bullet was the 225 gr Speer boat-tail spitzer, faring better than the more famous Sierra Game King which suffered a core separation (common among boat-tailed bullets) and an asymmetric folding back of the jacket. This latter feature I consider to be potentially a serious flaw because it suggests inconsistency of behavior (and this at a high impact velocity where things ought to be certain), although it could be the result of the bullet yawing in the test and no fault of the design.
I was amazed at the behavior of the big 275 gr Speer semi-spitzer. This bullet has a sectional density of .344 - thats the same as a 500 gr bullet of .458 caliber. If anything, this should be the one to drive like a runaway freight train. At a lower velocity it might, but it expanded more violently than the others (probably due in part to the generous amount of exposed lead in the tip). The wound cavity created can only be described as cavernous. Its not a bad bullet by any means, but possibly no more effective (at this velocity) against tough heavy animals than the little 200 gr Speer, which performed very respectably considering that its an ordinary inexpensive design.
Criticisms with this study might include the high velocity selected. Its true that at lower velocities the semi-spitzer would not have come apart like it did, but presumably the little 200 gr and the 225 gr boat-tail would also perform better. I question whether the 250 gr Game King would even function at an impact velocity below 2200 fps (this is a bullet design that would profit from a serrated jacket and/or a polymer tip insert). One might object to my attempt to remove the variable of velocity, because that implies that these bullets would arrive at targets of varying distance and therefore this is not a fair comparison. Perhaps so. I suspect that the 200 gr bullet loaded to its full muzzle velocity of 3200 fps would probably penetrate about 12 inches and lose 50% or more of its mass. This test (for the 200 grain bullet) corresponds to a range of about 175 yds in the .340 Weatherby but roughly the muzzle velocity from a .338-06 chambering. I wanted the test to be hard on the bullets because under those conditions differences should be most evident, but I feel that this range reasonably covers practical engagement conditions as well.