AR assembly problem......

[Bobula]

I have a DPMS lpk going into a Sabre lower, the bolt catch is EXTREMELY snug, to the point where it marred/scratched the finish going in, and was very difficult to move. Everything else went in flawlessly.

Where do I start?

[jjperl]

Just widen the groove about 1 thousandth of an inch with a fine file.

[Bobula]

Just widen the groove about 1 thousandth of an inch with a fine file.

Do I need to worry about refinishing or coating where I file in that channel?

[TonyM]

Do I need to worry about refinishing or coating where I file in that channel?

It's aluminum, so it's not going to rust. Plus, you should always keep some CLP on it anyway......

[Bobula]

CLP?

[10RoundLimit]

I would file on the bolt catch before the receiver.

[jjperl]

File what ever you feel comfortable filing, but if it were me I would file the receiver, just because you won't see it when you are finished. If you filed the catch you will be able to see it when your done, unless you refinish it.

[ar15barrels]

Always file on the cheaper part first.
In this case, that would be the bolt catch, not the receiver.

[Bobula]

would I be better off just ordering another bolt catch to see it it's the problem?

[ar15barrels]

would I be better off just ordering another bolt catch to see it it's the problem?

You could do that too.
Either way, if the receiver is actually the problem, I would still just modify the bolt catch to fit it.
Using that logic, ordering an extra bolt catch is a waste if it shows you the receiver is out of spec or it's a cheap fix if it shows you that your current bolt catch is out of spec.

[Bobula]

This is my first so I'm kinda

[Bobula]

I just tried the new bolt catch, the original is visably bigger, but this one is still a VERY snug fit, but it's not wearing the finish.
How tight is to tight?

[ar15barrels]

This is my first so I'm kinda

How tight is to tight?

When you hear a suction pop when you pull out.
There's no such thing as too tight.

Oh, you mean bolt catches?
They should move freely.

[vf111]

When you hear a suction pop when you pull out.
There's no such thing as too tight.

Oh, you mean bolt catches?
They should move freely.

.....I don't get it....

[Sydwaiz]

Bolt catches are all molded. It could be a little oversize if the mold was'nt clamped up all the way when it was shot. OR the cutter was dull when the slot was machined making it undersize. File on the bolt catch before filing the anodizing off the lower. You can touch up the finish on the bolt catch with some cold blue or reparkerize it if you have the skills!