Young NM upper and bolt carrier - interference fit issue

[SmokyJoe]

For the second time now, I’ve had fitment issues with Young Manufacturing side charge uppers and their NM carriers. The bolt carrier is too big to fit into the upper. Not sure if the upper is milled a bit small or if the bolt carrier is milled too big, or perhaps the chrome coating is too thick, but the two don’t work together. Bolt carrier will not go into the upper.

Last time around Young was good about quickly swapping parts to get me up and running. Now it’s happened again. They are responsive and are working on it but I have to wait for more parts to become available. Their product is excellent, and I like their side charge uppers, but this is getting old.

For added context, I have purchased the uppers and the bolt carriers at different times, so, not shipped together.

Anyone else run into this issue? Creative solutions?

 

[MontanaMan]

Their NM-BC's are slightly oversize by design & may be snug, maybe too snug in some uppers.

Usually you can lube them up & work them in by hand, unless you think it's too snug for that.

MM

 

[SmokyJoe]

Yep, I found that they should be bought together. Young took care of this pronto, but, better to buy them from same source at same time to make sure they run together.