Originally Posted By Dano523:
Suppressor not helping the cause, with the amount of fouling that is blasted back into the action from it, but would really need to see the carrier key, and even the top of the carrier flats to the sides of the key, since these are the mating  surface parts (with fouling), that is causing the accelerated wear.

And to note, most 223 gun powders take more than 18" to achieve full burn, so with short barrel, lot of unburnt powder pushed to suppressors baffles, and then blasted back into action via blow back pressure from the suppressor.

And the part that is not making sense on some of the rigs (short of a phone booth fire fights), something like 9mm CMMG Radial Delayed Blowback System bolt and barrel , barrel shorted to about 14.5", to run 9 major ammo with 224Gr cast powder  coated trunicated design bullet moving about 2Kfps out of the muzzle, better  wider penetration channel , and more devastating with flying ashtray hp bullet to transfer all the energy in the first few inches.  

Also to point out, hell of lot cheaper to reload 9 major with HS6 at around $.04 per round (22lr ammo cost), then is it to load 223 in the first place.

Simply , 223,  55gr out of 11" barrel, about 2300fps, 645lb muzzle energy
On the other hand, 9 major, 124gr out of 14.5' barrel, about 2000fps, 1101lbs muzzle energy instead.
And no, powder coated cast bullets will not lead barrel at speed of over 2Kfps, and even safe to use in tenifer/mellonite/carbonized treated bores for the same reason as well.