If you watch his videos you can start to pick up on certain trends. I notice bullets that achieve >1000 fps seem to cause more internal damage than bullets that achieve <1000 fps. The slower bullets seem to just punch a straight path and not "churn" up the gel. Some of the Underwood Ammo 10mm offerings in the 1500-1600 fps range produce a damage path that looks similar (not the same) to a .223 damage path. I think that velocity and bullet construction is playing a bigger role in the wounding abilities of these bullets than the actual size of the bullet. Categories. 115 grain+ weighted bullets >1250 fps 115 grain+ weighted bullets >1400 fps 124 grain+ weighted bullets >1200 fps 124 grain+ weighted bullets >1250 fps 165 grain+ weighted bullets >1000 fps 200 grain+ weighted bullets > 850 fps Each individual category has some tradeoffs. 115 grain+ weighted bullets >1400fps produce a large damage path but also produce shallow penetration. 124 grain+ weighted bullets >1200 fps offer a balanced mix of large damage path and adequate penetration. 165 grain+ weighted bullets >1000 fps create adequate penetration, but not always a large damage path. 200 grain+ weighted bullets >850 fps penetrate deeply, but do not produce a large damage path. In regards to 155 and 165 grain bullets traveling >1150 fps, I don't have enough data to make any meaningful observations. With the data produced by tnoutdoors9, I can make a few hypotheses: The best all-around performers based on the data available, appear to be 124 grain+ weighted bullets >1200 fps and 165 grain+ weighted bullets >1000 fps. This could change with additional testing of 155 grain bullets traveling at 1300/1400 fps, 165 grain bullets traveling at 1200/1300 fps, and 180 grain bullets traveling 1100-1300 fps. Testing of the Underwood .45 ACP 185 grain GDHP at 1200 fps and 230 grain GDHP at 1000 fps would be interesting and are necessary missing data points. The only conclusion I can draw from the current data points is that 1000 +/- 25 fps seems to be a threshold for creating a damage path. Bullets moving slower than 975 fps appear to mostly push straight through. These are just my observations. These could also be meaningless as simulating actual live tissue is much different than a ballistic medium.