Bolt won't lock to rear

[Marine24]

I haven't taken the bolt catch apart yet, but figured I'd ask this question here before seriously looking at this issue.

Problem I'm running in to is that the bolt on my AR won't lock to the rear when I engage the bolt catch or even when I have an empty magazine inserted.

I can retain the bolt by pressing on the bolt catch (lower portion) but as soon as I let loose of it, the bolt goes home.

I'm thinking the spring is either missing or defective but curious what others might have to offer.

[nogaroheli]

If you take the upper off you can feel the bolt catch on it's own. Check the spring like you mentioned and see if you notice anything else weird. FWIW, I had a Sabre Defense lower that had some burrs in the slot the catch moves in, I had to file them out and then it was good to go.

[Marine24]

I'll do that. Even though both the upper and lower are Yankee Hills, this build has been an odd one. Holes for the takedown pins didn't line but a little touch with the dremel tool fixed that problem.

Bolt catch doesn't seem to have the tension that it should and expect the spring is laying around in my workshop somewhere instead of in the lower receiver where it should be.

[legaleagle]

read your post, assume you got it fixed based on date. However, I would gather the spring is there, as the spring is what returns the bolt catch to its resting postion to allow the bolt to move forward. In short, I wonder if you have the wrong spring in it or too strong of a spring. You might also check the bolt catch to make sure the mating face to the bolt is flat and not slanted acting like a ramp. This is also true of the bolt face too.

[Tbag]

If you built it, any chance you used the disco spring instead of the bolt catch spring? They look similar at a glance.