ar upper assembly bolt group questions and pre post ban questions

[Leaky Waders]

Hi,

I only have one EBR - a bushmaster xm15 e2s in clinton era configuration.

I was looking at uppers on bravo company's website - LMT and BC brands. It appears that you have to purchase bolt carrier groups seperate.

The bolt carrier groups come semi and auto - what's the difference?

I thought the big thing about a semi vs auto was some part with the sear or trigger group on the receiver. (I'm not try to make an auto. I'm just wondering which bolt group is most versatile).

Also, now that the ban has sunset...is it ok to put any upper I damn well please on my lower (within minimal length reason) or do I still have to conform to some weird legislation?

Thanks,

L.W.

 

[Zerodefect]

Yup, you can swap uppers freely.

The auto carrier is heavier, The semi has a piece ground off so it can't be used in a auto conversion, I think?, never have owned a semi carrier. I just get the auto carriers. Don't even know why they make semi carriers any more.

the BCM Ion bond auto carrier is nice.