ar 15 problems

[drh777]

help please, so i just got me 2nd ar 15 lower receiver today, its a JD machine lower with Sacramento Black Rifle rollmark on it. So i went to go in stall my lpk in it this afternoon, and found the bolt catch to be very tight in the reciever, and hard to move. so I took it back out and checked the roll pin to catch clearance... it was good moved freely, so i put the bolt catch into my stag lower (thinking the bolt catch could be improperly sized) and it moved nice and free with no problems. so i took them both apart and found in my stag lower the groove where the catch sits into is machined nice and flush. on the JD machine/ SBR lower there is a step up inside the groove about an 1/8" in from the body of the lower where the ears for the roll pin are... basically directly inline where the "shelf"? the catch rests on in the reciever. and it seems to be causing the issue. I left JD machine an email but havent heard back yet. does anyone know if this is how they purposely machine there lowers over there or if this was a mistake? or do i need to assemble it all take it out to the range and sling a bunch of lead through it to get it to loosen up? Im sort of ocd about this sort of thing and after i spend alot of my hard earned cash and carefully assemble it i would like it to function like butter, nor do i want to load up and head out to the range just for my new toy to fail to operate and have to drive all the way back just hoping someone may have an idea or same issue? thanks much!

[Arteel]

That may be an issue. If the bolt catch doesn't move freely, it can cause the bolt to not lock back after the last round.

I would personally wait and see what the manufacturer says before assembling the receiver.

[SocomM4]

If its not perfect, then it's out of spec.

If you have a caliper, check it against this.

http://www.cncguns.com/downloads/AR15/AR15_blueprint-Model.pdf

[TATER313]

If you just emailed them give time to respond, hopefully they will resolve it for you.

[drh777]

Arteel, thank you very much for the response, I will deffinately wait to hear from them.
SocomM4, that diagram is great! thanks! Dont have calipers at home, but i can check it when I get to work tomorrow. My stag Im assembling, and my other ar are purpose built, hammered on have fun with rapid firing, dirty, scratched... ok wont make me tear up. I was planning on assembling this one as my "nice"? AR, for lack of a better term, trick it out and make it look bad*****, you know typical money pit. so I was going to take my time and do everything very carefully, end up with a very nice finished product and 1st step everything comes to a hault. bummer!