I sold a Bushmaster M4 upper to a SH member without bolt or charging handle.  He was going to use the bolt out of his Bushmaster Varminter for this same upper.  Varminter was relatively new, only a couple hundred rounds through it.  My question is that he appears to be having a problem chambering a round.  Would this cause a problem?  I may have to have him send it back to me if it won't work with what he has.

Let me know so I can help this guy out.

Thanks

Bill3508

Good on you for wanting to make it right...

What is his source of ammo, though the varmiter would likely have a slight tigher chamber than the M4 barrel.  Far fetched to think the bolt is actually tight, as they are/should be  held within a set tolerance throughout the industry.

I got some more info from him.  He says that with the bolt locked back and then released it jams the first round.  If he pulls the bolt back on a new mag it chambers fine.  He's using a pneumatic recoil system, though I don't see how this could cause a problem.  Ammo was black hills 52gr.  I don't know if he tried another magazine either.  He said he would try to work it out, so I told him to shoot it and if it still gives him trouble he can return it to me.  No reason for him to keep something that won't work with the equipment he already has.

Thanks for the help.

Bill3508

If its working with a new mag but not the original one used Id say mag problem.

Update:

He states it jams the first round with every mag.  So I'm going to have him send it back.  Not sure what the problem could be and I'll check it out when it gets back.  This was a new upper, only 50 rnd fired through it, using XM193 and no problems on my end.  I'll try to post an update when it gets back.

Bill3508