The LMT BCG does have the pads on the bottom. Some guys don’t get any carrier tilt, some do.
Many thanks, again, brother.
I don’t own a piston gun, I went w/ an LR300 but for those of us who don’t reload and buy cheap ammo at shows etc, the fact that these run so cool means that laquered and dirty ammo feeds great for a long time !
I tried a 16 inch 5.56 piston conversion and did not like the carrier tilt.
The annodizing in the buffer tube where the bolt carrier pads rub was gone in 40 rounds.
While the rest of the rifle was a lot cleaner than a DI MRP,
I still sold it off and decided to stay DI.
Not sure HOW MUCH COOLER the chamber would be but any amount would be appreciated. I once ran PCA polymer cased ammo at an EAG Carbine Course in Boone County, IN back in 2004/5. The ammo was fine on a static range shooting for accuracy. However, once we got to shooting strings I began to have issues. The heat would cause crazing (heating the long polymer strands to the point they become brittle) and I’d have case neck separation during combustion: Steve Fisher had to push two projectiles out of the barrel. (Steve, next time I’m in MI I’m bringing you two cleaning rods, brother - oh, Binkinz has been selected for Ranger School, too).
The ammo was very accurate but the temps killed it. PERHAPS, it would perform better with a piston gun… I’d not use it as home defense ammo, though. Soon, someone will come up with a polymer formulation that will make running “plastic” cases plausible. Can’t wait: the weight difference of a full mag of PCA vs. M193 was unbelievable. I was constantly checking my mags to see if they were actually loaded… 
Again I don’t own a piston gun but my LR300 is a totally different system then a DI gun and the gases do not go directly back to the bolt and receiver, it’s more like a piston gun as far as running cooler and cleaner. After 3 mag dumps ( approx. 90 rnds) the receiver is barely warm so laquered cases do not melt and cause problems like they do on a DI gun. I have also run 1500 rnd torture tests w/ no cleaning and no lube using cheap, dirty, lacquered ammo and no problems. My DI guns will not do this succesfully.