Elvis wrote:

looks like you need to treat those bergers to a detipping with the angle grinder before shooting!

I've considered doing that just haven't figured out how to do it so I have consistency from round to round. Considering I shoot other lead-core bullets into this trap and they fragment, I don't think this specific bullet is going to fragment when it hits a deer or elk without some of the tip removed. Unaltered, it will yaw and exit backwards out the far side.

As a result of an cow elk hunt last weekend, I recovered some GMX bullets to compare with those from the bullet trap. Below is a series of .277 130gr Hornady GMX shot from 100 to 500 yards. The bullet at 400 yards was recovered from my 500+ pound cow elk after 30" of penetration.

I also included a 165gr GMX shot from a .300 Win Mag at 75 and 500 yards. It does show that a large diameter bullet also expands to a larger diameter.

Here is a composite picture showing bullet terminal performance. The bullet entered 8 inches behind the diaphragm and penetrated approximately 30" to a rib in the left forward chest area. It took some force to pull the bullet out of the rib bone. The bullet passed through the heart. The recovered bullet is shown next the the trauma.

Tracy Short did an article on this awhile back as he does alot of shooting and deer out to 5-700yrds not the 12-1400 others claim to do!! and he said he had similar problems with hollows so recommended lead tips for better mushrooming, had tried filling hollow with wax etc to get it to start to open better which was better but not ideal. I believe alot of these fellas are using Amax but they arent the best before 300yrds as they will blow up. I havent had that problem with the ones I tried.
I used a big plastic bag for a bullet trap the other day and it worked ok with the projectile stopping in the oil container behind it.

Elvis, these GMX bullets have a ballistic tip which does help them open up fast. They mushroom to full size right away being full size after an inch or two of penetration.

You talk about a problem. What problem do you see here? I have found these monolithic copper bullets have mushroomed reliably and consistently 100% or the time. I also haven't seen them deflect or go off course once they impact - straight and true.

Directly from Hornady's website, regarding the A-MAX bullets, "•These bullets are not recommended for hunting." For the most part match bullets are designed to punch holes in paper, not critters. Those GMX bullets look like they are performing well. They were designed to penetrate well so they open up, but not excessively.

yip you have nailed it fair square there Pumpkin. and there in lies the catch 22. super accurate Vs great terminal preformance...... I believe these long range gurus are working on the theory that putting it in the right spot is more important and the slower impact velocity helps to keep them together.
Slim bud you sure as shooting dont have any problem that I can see... well other than steak or stew for tea????
I love the research you have posted here and it has really got me thinking(no mean feat at any time) I have never really worried about the projectile too much but what I have seen here shows what is possible with a little effort.
Thank you again.

Yep Elvis, you're right and even my shoulder is very interested in all these 'Slim's-tests'. I've always believed that when I wanted to be double sure, I had to take a larger caliber. I never tested performance of my bullets in the .300 WM because I know they kill everything and always. I did some test in the .375 H&H, but for the other requirements: to get a load that would still leave me some eatable meat of a roe deer shot with an elephantrifle...

But SJ takes a light handsome small caliber rifle and is killing an animal of elephant's size at a distance I cannot find my target anymore, even when using binoculars...
Quite different from me: I like to use funny stuff (such as lead bullets or small FMJ's upside-down) on short distances.

Thanks, Elvis. These GMX bullets may not be match bullets but I'm well under 1 MOA, often shooing 1/2 MOA groups at 100 yards. I think my biggest long range accuracy issue is the the IMR4350 powder. I can lose 50 fps going from a warm to a cool day. On this trip, I carried my bullets/mags in my pockets next to my body to keep them warm. I'd try a different powder buy I have 10 pounds of 4350 left.

Also note that the .308 bullets mushroomed to a larger diameter but that affects penetration. My .270 130gr GMX penetrated deeper than the .300 Win Mag 165gr GMX at 500 yards.