[RangeRat234]

After fully assembling my first AR build, the bolt does not go far enough back to engage the bolt catch. I have swapped complete lowers, and my upper works fine. I swapped bolt carrier groups/ bolts.I swapped out buffers and buffer springs in my lower and it will not catch. Any other ideas?

DPMS lower, DD lower parts kit
ATI buffer/tube/spring kit (Comm.)
YHM upper by Precision Firearms

[Jpyle]

Originally Posted by RangeRat234

After fully assembling my first AR build, the bolt does not go far enough back to engage the bolt catch. I have swapped complete lowers, and my upper works fine. I swapped bolt carrier groups/ bolts.I swapped out buffers and buffer springs in my lower and it will not catch. Any other ideas?

DPMS lower, DD lower parts kit
ATI buffer/tube/spring kit (Comm.)
YHM upper by Precision Firearms

Are you saying the bolt doesn't move rearward far enough or that the catch doesn't engage? Do you have an empty mag inserted or are you manually engaging the stop? Did you dry fire the lower, not pinned to the upper" and allow the hammer to hit the bolt catch?

Pics would help...

[RangeRat234]

When manually engaging the bolt catch,the bolt fails to travel far enough rearward to allow the bolt catch to hold the bolt face. 1/8ish inch. The app crashes when I try to add the pic...

[Jpyle]

Don't know if its the angle but the catch doesn't appear to be seated properly. The catch should appear as a small triangular stub that sits on the magwell rim with a small tail that protrudes into the magwell. When an empty mag is inserted the follower should visibly raise the entire mechanism and capture the bolt as it draws backwards. In the pics it appears that the body of the catch is below where it is needed to engage.

There are only 2 other places that the bolt can be impeded, the hammer, if installed incorrectly or at an angle may catch on the underside of the carrier or the entire carrier may not clear the buffer tube opening. You would really need to be out of spec for that to happen. You did mention that you have a commericial tube, are all the buffer, tube and spring commercial? Mixing and matching mil-spec and commercial may create a pinchpoint although the parts may appear to fit properly. You may also want to be sure that the buffer is not making contact with any screw in the stock, if the buffer is held up so will the bolt.



Just for the hell of it here's a diagram. The bolt catch spring and disconnector spring are easily confused, check to make sure you got it right.

[mjkeat]

I wonder if the buffer is to long.

[Jpyle]

Originally Posted by mjkeat

I wonder if the buffer is to long.

OP says he has switched out spring and buffer. I'm kinda stumped here myself no obvious place for the bolt to hang up unless it's hitting the hammer

[mjkeat]

Thats weird.

Like you said it could be the catch. Other than that I have no idea.

[RangeRat234]

Here are some more pics. Buffer, tube, and spring are all Comm.they came in a kit. No screws to hold up on. Hopefully the pics help ...in the last pic I am pushing the bolt back into the buffer/spring while pushing the bolt catch.

[FCross7]

Aren't the rifle length buffer springs and carbine buffer springs different lengths? Could it be that he's got a rifle length spring in a carbine receiver extension?

-Fred

[FCross7]

Originally Posted by FCross7

Aren't the rifle length buffer springs and carbine buffer springs different lengths? Could it be that he's got a rifle length spring in a carbine receiver extension?

-Fred

I just measured the buffer spring in my rifle and it's about an inch shorter than yours, so I'm thinking you have the wrong spring in there.

Can anyone else confirm this?

-Fred