Help needed with AR OLL build.

[F4E Phantom]

I finally got around to building my Fulton Armory OLL. It is one of the original famous Milpitas lowers. I also have one of the infamous seized OLL but that's another story. My problem is: the bolt will not go all the way back into the buffer tube(A2 Stock). When I take the rear take down pin out and separate the upper a bit , the bolt will travel all the way to the rear. I have tried two different uppers (BM and Colt) and got the same problem. Any suggestions will be appreciated. Thanks to all.

[gregorylucas]

Spec.

It sounds like your upper(s) are sitting at a slight angle fron the plane of the lower receiver.

Almost sounds like your lower pins are out of spec. Are they level with the lop of your reciever? In other words is the front and rear pins the same distance from center from the plane of the lower receiver?

It could also be there is something wrong with either the buffer tube or spring. is the tube engaged fully with the lower or it cross screwed on?

Have you tried a different lower?

I hope this helps.

[F4E Phantom]

gregorylucas, thanks for the reply. these two uppers I tried are proven to work with other lowers I have. The buffer spring is not binding. The tube looked straight, and went on easily. The two pins holes might be dimensional okay to themselves but are out of location to top plane of the lower reciever. I suspect a bad lower because the trigger pin holes were oversize( they should be .154-.155" dia. theses holes were .1575!. Thanks for the ideas.

[ar15barrels]

The bolt should only travel about 1/4" more than it needs to be able to pick up the next round from the magazine.

Is there some random chance that you are building a 308 and you have used a 223 buffer?
If so, you need a 308 buffer which is shorter and will allow for more bolt travel.

[F4E Phantom]

Thanks for the input. I bought the A2 stock assbly on Gunbroker. I will compare the buffer to my original AR A2 buffer. Good day.