Out of a non-chrome lined 1x9 twist 16", I have recovered several targets with puncture holes that resemble the exact shape of the side profile of a bullet. Each target was stapled to a tree so I wasn't sure if the weird shape was due to actual tumbling or if the unique green-tip LAP bullets mis-shaping immediately upon impact. Shooting regular Winchester 5.56 55gr FMJ, the hole is a perfect circle as I am used to. This PMC X-Tac 62gr LAP ammo has produced these weird holes up to 40 yards, yet has been just as accurate. Are my bullets tumbling and why? Is this bad for the barrel? The round also feeds a bit rougher than the regular FMJ, however the rifle has never skipped a beat while firing the. Not one hiccup. I have invested in hundreds of these rounds so I am sort of stuck unless this is normal for what I should be expecting with this round.

Shoot a few at 200yd if you can. You can hear the difference between stable and tumbling bullets. The tumblers will have a "whiiiiiishh" kind of sound to them. Also, accuracy will be about a 10ft wide pattern at 200yd if they're not stable.

I shot a box of 62gr. lead core stuff out of an old M16a1 upper (1:12" twist) and they would be stable to about 100yd, then you'd hear them flying sideways. Scary sound to be honest.

This... It seems like the bullets fragmenting and/or ricocheting off the wood is what is causing the strange holes. Have you tried shooting the ammo at a target with a soft backing like a piece of cardboard? This will give you a better result, I think.

I shot the X-TAC 62gr from several different rifles at paper - clean round holes. I was not very impressed with the accuracy of this load, so-so at best, the 55gr PMC grouped better in every rifle I tried.