Generally speaking pistols are very low vel with relatively very large dia bullets. Compound that with an expanding bullet and you will have results like hitting a pig in the head 4 times with out killing it. A 22lr has much higher vel with relatively small dia which results in fully penetrating the skull and brain. One and done. This is why a 22lr works well for slaughtering livestock and and big handguns do not.
This is why we do not want our Jack Hammers to expand. Putting your life in the capability of a handgun is sketchy. It gets very sketchy when the bullets expand.
Maybe I’ll try loading some up in 40 S&W cases and testing them, I think I still have some 40 brass sitting around from a gun I sold years ago. My GP-100 test gun is going out on Monday to get reamed out to 10mm Mag, but should be back in a few weeks. I’ll run some 40S&W loads through it then.
If I can get a good source for pig skulls I’ll try shooting a few with the Jack Hammers. I tend to think the reason we hear so many stories about bullets “bouncing off” of pig skulls has more to do with their shape than anything. It’s like their skulls are designed to deflect bullets! Unless the hog is looking down, there’s really no flat surface for a bullet to impact, so the skull is just like a ramp.
One thing I like about the jackhammer design is the relatively sharp front edge design so that it will turn in towards the center of mass when encountering skin over bone, to a degree. Smooth rounded edges tend to follow the bone just under the skin without penetrating the bone.
Here's an update, and an update to the update. LOL I've been posting most of this over on the Hammer Time forum and didn't update this thread with the second round of testing. Here's a copy of the post on the Gen 2 Jack Hammers I posted last week on the other forum.
I got another round of testing done with the 10mm Jack Hammer bullets. This time I shot the Gen 2 version that Steve sent me which has a deeper "dimple" in the nose. Here's the Gen 2 Jack Hammer on the left compared to the Gen 1 I tested previously.
All of the loads tested today were the same as those tested before. There's a slight weight difference between the Gen 1 and Gen 2 Jack Hammers, but I don't imagine it made enough of a velocity difference to have a meaningful impact on performance. Shooting was done at 15 yards into 20% ballistics gel from Clear Ballistics and all rounds were fired from the Kimber 1911 in 10mm. The total number of rounds fired was fairly limited due to breaking a finger on my left hand yesterday. While I am right handed, it still wasn't terribly fun to do much shooting today with the crooked finger!
The primary goal with the Gen 2 Jack Hammer with the larger "hollow point" was to get the bullet to expand to full bore diameter after impact. This would allow these bullets to be legally used when expanding bullets are required for big game hunting (which they are here in Washington state). I only fired two of the new bullets into the gel today, but neither one showed any sign of expansion after impacting the 20% gel.
Bullet penetration was also reduced when compared to the Gen 1 Jack Hammer. The 220gr and 200gr cast bullets performed similarly to the previous test shooting into bare ballistic gel. Only one 200gr bullet and one 220gr bullet were fired into the gel this time. The third bullet in this picture is actually a 275gr Sledge Hammer fired from a 45-70. I'll give the info on that bullet in another thread.
- Gen 2 Jack Hammer 24" (both bullets)
- 220gr cast bullet 23.5"
- 200gr NOE WFN cast bullet 32"+
The 200gr cast bullet actually exited the second block this time. The 220gr bullet penetrated the same distance as it did in the previous tests and flipped backward again. Both of the Gen 2 Jack Hammers performed consistently but did show less overall penetration than the Gen 1 did in the same test. The temperature was slightly warmer today which may have influenced the consistency of the gel blocks, but that seems unlikely. Shooting the Gen 1 side by side with the Gen 2 would have been a more accurate test and I'll do that next time.
I still need to pull still photos from the video to show the temporary wound cavity, but the Gen 2 does appear to show an increased temporary wound track when compared to the Gen 1. I should have the video from all of the testing edited in a few days and I'll post it when it's done.
Right now it doesn't appear that the larger "hollow point" in the Gen 2 is having the desired effect, at least when fired into pure gel. The next round will have the bone mixed in which may give different results. As before though, functioning was 100% as long as the loaded OAL was kept to 1.240" or less. Because of the wide nose profile of the Jack Hammers, a longer OAL causes the bullets to hit the front of the magazine and cause feeding problems. This probably wouldn't be an issue in a Glock or any other double-stack magazine, but the narrow 1911 magazine can be a little restrictive with some nose profiles.
Here's todays update on the Gen 2 Jack Hammer, and a follow up on the Gen 1.
We have expansion! I took the Gen 2 Jack Hammer to test it on the Armorcore board and I got the Jack Hammers to expand exactly how we want them to. As it turns out, the Gen 1 Jack Hammers perform almost identically when shot at the same board.
On the left is a recovered Gen 2 and on the right is a recovered Gen 1.
This is the board that I'm shooting them at. It's a fiberglass laminate that's roughly .500" thick. I was shooting at 40 yards and this is what the bullets look like in the board. I fired a total of 24 shots at the board and nothing penetrated completely through.
I'd say the Jack Hammers are good to go at this point. They expand more than hardcast lead does under the same conditions and they have very similar terminal performance. I'm going to test them one more time in the gel, but use an elk vertebrae this time. I think if they hit something more solid than the shoulder blade I used the first time, I'll be able to get expansion in the gel.