Stag 15 firing problem

[teacher74]

I have been trying to read through the forums and search but couldn't find the answer to or figure out the right search combination for this.

I recently have built up a stag 15 rifle, following the instructions from AR15.COM. Today I took it out for it's first test run and had a problem. The gun shoots just fine, but will not fire a second round. It has no problem chambering the first round and firing it. It then ejects the spent case and chambers a second round, but will not fire that second round. I have to manually eject that second round and the next round will chamber and fire, the follow up round will chamber properly, but will not fire.

Since the rifle does shoot, I am assuming that I may have done something wrong in the assembly of the lower.

Does anyone have an idea as to why this happened and what can I do about it?

Thanks in advance

[FlyingPen]

Did you install your buffer, spring, and buffer tube correctly?

[PolishMike]

Do a function check on the lower. Make sure the hammer isnt riding the BCG. Take the upper off and google "AR function Check"

[jacques]

What kind of Ammo are you using?

[Rocko]

Check your hammer spring.

[ty423]

maybe the hammer isn't resetting.

[aplinker]

Could be short stroking, too.

[jacques]

Could be short stroking, too.

Cheap Ammo? New gun?

[aplinker]

Cheap Ammo? New gun?

Misaligned gas system, too.

It's clearly feeding the 2nd round.

My question is, do you hear a click, or does the hammer not drop?

Come to think of it, it's unlikely a round would be chambered without the hammer cocking.

If you're not hearing a click it's most likely a lower issue (misassembled trigger).

[ar15barrels]

Disconnector problem or disconnector spring is missing/backwards.
If the spring is missing, you are getting hammer-follow.
Your finger is off the trigger when you rack the charging handle to chamber the 3rd round so the trigger retains the hammer and you can fire every-other round.

The large end of the disconnector spring snaps firmly DOWN into the trigger.
This seems backwards because the disconnector spring fits freely into the trigger if you put the large end UP.