WyoWild
WKR
- Joined
- Oct 26, 2021
- Messages
- 635
When considering the performance of different bullets & cartridges there is often a contested and emotional debate about what constitutes optimal killing performance. After reading the Hornady LEM test & application guide I thought this would serve as a more objective way to estimate some aspects of would channel size and performance. These test are done using organic calibrated ballistic gel. This is known to be the best analog to animal tissue. The clear gel used by most YouTube tests does not translate as well to performance on tissue.
The full source material can be found here:
file:///C:/Users/VHASHE~2/AppData/Local/Temp/1/MicrosoftEdgeDownloads/37ef4786-1d36-420a-8356-ed296f525587/1410996103-1704221297-TAP-Application-Guide.pdf
Testing is done by firing into the gel at a distance of 10ft with a variety of bullets: (BTHP, Tipped Cup/Core & Copper depending on cartridge) Tests both bare gel plus a variety of other overlays including heavy clothing, two pieces of 20g steel (car door simulant), wallboard (two pieces of gypsum dry wall), 3/4" plywood, auto glass.
Measurements include the entry/neck to expansion, maximum temp wound cavity, depth to max cavity and total penetration.
For this discussion I have used the performance on bare gel to simulate a broadside shot where minimal resistance is met and plywood to stimulate moderate bone hit like shoulder blade/rib. This is likely tougher to penetrate than these thin bones but not a tough as a deer/elk humerus. I thought the heavy clothing would be an interesting comparison to tough animal hide but this simulant was only used for some projectiles so could not be usen when comparing all bullets.
Using the temp wound cavity dimensions I used an ellipsoid volume calculation to get some idea of the total volume of tissue affected by the temporary wound cavity. I would assume there would be some correlation between temporary and permanent wound cavity as the dramatic displacement of tissue causes tearing as it reaches its limits of elasticity. Unfortunately this data does not provide a measurement of the permanent wound/crush cavity.
You can definitely observe a trend that the lead cup and core bullets produce larger wound cavities. You can also observe bullet fragments producing a larger permanent wound cavity although it is difficult precisely measure or estimate this volume. Hornady does not provide permanent wound cavity measures.
Perhaps someone with more knowledge and experience can weight in on the relationship between temporary and permanent wound cavities as it pertains to lead cup/core bullets & monolithic projectiles. Would be interesting to see if there was a percentile correlate.
Some takeaway observations from this review.
Temporary wound cavity size generally increases as the size & weight of the projectile increases. I was impressed with the 6 ARC temp wound cavity. A 2 liter sized area of disrupted tissue. With a fragmenting cup/core bullet & looking closely at the images it would appear that the permanent crush cavity would be at least 50-75% of that volume. That would be the equivalent of nalgene sized permanent wound all the way thru the chest cavity of a deer to elk sized animal. IMO that is a devastating wound that would result in a quick death.
The 300 Win Mag produced a temp wound cavity that was about twice as large as the 6 arc but penetration was similar. When looking at recoil in a 8lb gun a 6 ARC has 6.7ft lbs and a 300 Win Mag would be at 26.8 ft lbs. 400% more recoil to produce a double sized temp wound. Again this is the temporary would cavity and not the permanent wound but I would assume that the permanent crush cavity would be about double as well.
Hitting resistance like plywood did not lead to more extreme fragmentation of lead bullets and only a slight loss of penetration. Would extrapolate that ungulate ribs & shoulder blades would not hinder bullet performance. Hitting resistance with monos may actually increase the temp wound channel volume, I would assume this is because hitting something solid helps that harder bullet fully expand earlier.
The full source material can be found here:
file:///C:/Users/VHASHE~2/AppData/Local/Temp/1/MicrosoftEdgeDownloads/37ef4786-1d36-420a-8356-ed296f525587/1410996103-1704221297-TAP-Application-Guide.pdf
Testing is done by firing into the gel at a distance of 10ft with a variety of bullets: (BTHP, Tipped Cup/Core & Copper depending on cartridge) Tests both bare gel plus a variety of other overlays including heavy clothing, two pieces of 20g steel (car door simulant), wallboard (two pieces of gypsum dry wall), 3/4" plywood, auto glass.
Measurements include the entry/neck to expansion, maximum temp wound cavity, depth to max cavity and total penetration.
For this discussion I have used the performance on bare gel to simulate a broadside shot where minimal resistance is met and plywood to stimulate moderate bone hit like shoulder blade/rib. This is likely tougher to penetrate than these thin bones but not a tough as a deer/elk humerus. I thought the heavy clothing would be an interesting comparison to tough animal hide but this simulant was only used for some projectiles so could not be usen when comparing all bullets.
Using the temp wound cavity dimensions I used an ellipsoid volume calculation to get some idea of the total volume of tissue affected by the temporary wound cavity. I would assume there would be some correlation between temporary and permanent wound cavity as the dramatic displacement of tissue causes tearing as it reaches its limits of elasticity. Unfortunately this data does not provide a measurement of the permanent wound/crush cavity.
You can definitely observe a trend that the lead cup and core bullets produce larger wound cavities. You can also observe bullet fragments producing a larger permanent wound cavity although it is difficult precisely measure or estimate this volume. Hornady does not provide permanent wound cavity measures.
Perhaps someone with more knowledge and experience can weight in on the relationship between temporary and permanent wound cavities as it pertains to lead cup/core bullets & monolithic projectiles. Would be interesting to see if there was a percentile correlate.
| Cartridge/Bullet | Velocity - FPS | Estimated Temp Wound Volume (Cubic Inches & Liters) | Total Penetration & Retained Weight % |
| 223 75gr Lead BTHP - Bare Gel | 2542 | 115 ci or 1.9 L | 12.5" & 36% |
| 223 75gr Lead BTHP - Plywood | 2544 | 90 ci or 1.5 L | 13" & 51% |
| 556 70gr CX - Bare Gel | 2652 | 65 ci or 1.0 L | 18" & 97% |
| 556 70gr CX - Plywood | 2659 | 55 ci or 0.9 L | 16" & 92% |
| 6mm ARC 106 lead TAP - Bare Gel | 2647 | 170 ci or 2.8 L | 18" & 73% |
| 6mm ARC 106 lead TAP - Plywood | 2645 | 95 ci or 1.6 L | 15" & 39% |
| 6.5 CM 147 ELDM - Bare Gel | 2646 | 142 ci or 2.3 L | 16" & 47% |
| 6.5 CM 147 ELDM - Plywood | 2676 | 127 ci or 2.0 L | 15.5" & 55% |
| 308 Win 168 AMAX - Bare Gel | 2537 | 199 ci or 3.2 L | 14.2" & 72% |
| 308 Win 168 AMX- Plywood | 2562 | 177 cu ir 2.9 L | 17" & 76% |
| 308 Win 165 CX - Bare Gel | 2735 | 157 ci or 2.5 L | 29" & 99% |
| 308 Win 165 CX - Plywood | 2583 | 175 ci or 2.8 L | 27" & 100% |
| 300 Win Mag - 178 ELDM - Bare Gel | 2894 | 300 ci or 4.9 L | 14.25" & 41% |
| 300 Win Mag - 178 ELDM - Plywood | 2891 | 268 ci or 4.3 L | 13.5" & 55% |
Some takeaway observations from this review.
Temporary wound cavity size generally increases as the size & weight of the projectile increases. I was impressed with the 6 ARC temp wound cavity. A 2 liter sized area of disrupted tissue. With a fragmenting cup/core bullet & looking closely at the images it would appear that the permanent crush cavity would be at least 50-75% of that volume. That would be the equivalent of nalgene sized permanent wound all the way thru the chest cavity of a deer to elk sized animal. IMO that is a devastating wound that would result in a quick death.
The 300 Win Mag produced a temp wound cavity that was about twice as large as the 6 arc but penetration was similar. When looking at recoil in a 8lb gun a 6 ARC has 6.7ft lbs and a 300 Win Mag would be at 26.8 ft lbs. 400% more recoil to produce a double sized temp wound. Again this is the temporary would cavity and not the permanent wound but I would assume that the permanent crush cavity would be about double as well.
Hitting resistance like plywood did not lead to more extreme fragmentation of lead bullets and only a slight loss of penetration. Would extrapolate that ungulate ribs & shoulder blades would not hinder bullet performance. Hitting resistance with monos may actually increase the temp wound channel volume, I would assume this is because hitting something solid helps that harder bullet fully expand earlier.
