Bolt Problems On My AR

[SureShot241]

When I first fired my home built AR-15, it performed well except 2 problems:
-Feeding Issues
-Bolt not being held open after last round

People told me it was probably due to the fact I had a really cheap mag. So I bought Pmags (which I Love!) and fired my rifle for the second time today. First time I fired I put a little over 100 rounds through it, and this time I put about 130 rounds through it.

The problem with feeing has gone away, so I think the mags helped with that, but the bolt problem still remains.

Any ideas on why my bolt wont stay open after last round has been fired?

Here is a link to what my rifle is composed of:

http://www.calguns.net/calgunforum/showthread.php?t=398896

[bender152]

If you manually hold the bolt catch and rack the bolt, does the bolt stay open?

[SureShot241]

If I hold the bolt catch down the bolt does not stay open, If I just cock the bolt without touching the bolt catch it holds it open.

[G-forceJunkie]

What ammo? What weight buffer in it?

[SureShot241]

I have used 2 different kinds of ammo, Remington and Federal, both ram fine in other rifles and seem to run fine in mine, and I cant find the specs on my biffer but its a DPMS buffer.

[Sky_DiveR]

If I hold the bolt catch down the bolt does not stay open, If I just cock the bolt without touching the bolt catch it holds it open.

Could you clear this up abit?

If you put in an empty mag and pull the charging handle, does the bolt stay open?

[SureShot241]

Could you clear this up abit?

If you put in an empty mag and pull the charging handle, does the bolt stay open?

Yes it stays open. The ONLY time it fails to stay open is after last round is fired. I have no idea why.

[Hump0311]

Do you have the lot numbers and grain weights of the ammo you fired?

We can start narrowing down your problem one step at a time.

Your have a malfunction with your feeding, chambering, locking.

Let's starting eliminating.

[Twoodland]

Sounds like a short stroke. If the bolt is being held open when he racks the gun with an empty mag in, then that means the follower is pushing up the bolt catch properly. However, if it fails to catch after the last round, that means the bolt is not going back far enough on the last round. This malfunction seems to be common on fresh ARs

[SureShot241]

55gr Ammo. And I dont have the lot number. But the ammo was fired with 2 other guns than mine today at the range and no problems with theirs. Its Remington UMC ammo though.

[Jaxpire]

Sounds like mag problems to me, try with some other brand of mags?

[SureShot241]

Pmags shouldnt have any problems, the people I shot wit used the SAME mags as me, bought at same time, and they had no problems

[Jaxpire]

Yeah shouldn't, but did you try anyway?

[SureShot241]

well I used a dfferent mag last time and had same problem.

[Twoodland]

I think a mag problem after replacing the mag with a brand new P-mag is very unlikely. Especially when he said if fixed his feeding problem and he put 230 rounds through it without feeding failures. Also he said that when he pulls the charging handle back with an empty mag, the bolt catch holds the bolt back correctly. sounds like the mag is fine. Like i said in post #9 it sounds like the bolt is not coming back far enough.