AR15 bolt release fail

[ebb]

My friend has built several ar15s from an 80 percent lower and Bear Creek side charger lowers all of the bolt hold open releases are jammed tight won't move when upper is installed. They work freely with no upper is on the lower. Is this a compatibility issue with the uppers? Does the mag release need to be fitted with some installations?

 

[jelenko]

Any chance there is a extended bolt release installed? E,g, Magpul BAD lever?
If the upper receiver is 'fatter' than standard, the extended bolt releases can be pushed out by the wider upper.
And, just to confirm, when you mention mag release in your last sentence, you meant bolt release, yes?

 

[Walt Krafft]

Those are problems related to poor machining / dimensional issues with your lower. A properly machined lower does not have any fitting needed for any of the standard milspec parts.

 

[Dusty Stevens]

Look and see where it hits the upper. It has to be very obvious

 

[ebb]

No add on parts just a standard bolt release. All of these lowers work with other uppers but not with the Bear Creek uppers. The BC uppers are all side chargers and i didn't get a good look last night when I was there but the bolt carrier looked different than standard.

 

[Downhill]

I had to polish the sides of a bolt release with the same issue being described. Just removed finish and problem was corrected. My thought was that the bolt release was out of spec a bit.

 

[jelenko]

Look and see where it hits the upper. It has to be very obvious

To Dusty's point, can you post a couple pictures focusing on the bolt release? One with just the lower and one with the upper attached to the lower?
For the one with the upper attached, it would be best to have a 'side' view so you can see where the bolt release is touching the upper.

 

[ebb]

My friend sent pictures to Bear Creek and got to talk to a very nice and knowledgeable young man named Lucas. Lucas says looks like an AR10 bolt release to me, can you compare it to a known AR15 bolt release. So they did and guess what, the other guy that was putting his gun together had brought 2 AR10 releases and they got used in the AR15 guns. They both said they could not be more pleased with the uppers and help the got from Bear Creek and from Lucas.