To address the OP's question, I have both a .45-70 and a .458 SOCOM. The .45-70 is very versatile and can be quite powerful, but an AR with that much THUMP is a lot of fun.
I am a .45-70 guy but the Bushmaster and the SOCOM interest me.
My biggest problem with the AR is throwing. 75 to 85 cents on the ground every shot.
Here is a full auto Bushmaster at Texas Guns. The last part of the video is best. About 30 seconds total.
https://www.facebook.com/texasgunshop/videos/1691120264237731
