I got an email back from Bushmaster in regards to a question of whether you can use 5.56 ammo in the R15 that is marked .223 rem on the barrel. The following is the email I got back from technical support for Bushmaster.
30 Remington AR is a pretty stout round (Pressure) and the lightest profile barrel is the Remington R15 which is .980 over the chamber tapered to .750 at the gas block and .680 at the muzzle. A 22 inch medium profile barrel on a rifle length gas system , that upper weighs 5.5lbs. The DPMS as sold in 16" Bull weighs in at 5.5lbs.
Temp stability is why I do not use R15. I use a fairly closed gas system (suppressed shooting) and 8208 is way under powered even at near max/max loads. The brass barely ejects. And when it gets too hot, it wasn’t showing warning signs like cratered primers or swipes. It went straight to blowing primers out I live in SC.
R15 is the default avatar body and animation rig in Roblox, which has more joints than R6 and is able to bend. The model is named after the number of body parts it has (15 parts) instead of 6 (R6). The model was available to the public early in the form of a testing place. As the description of the experience says, all the current animations are temporary, and thus will most likely be changed ...
I expect the old R15 pose to be reintroduced as the default option for avatar thumbnails, allowing users to showcase their creativity and personality through more dynamic poses.