Educate me please....question about SBR and BCG.

[Eric D.]

That's usually what happens. I don't have an explanation for why the enhanced bolt is the problem.

The buffer's primary function is to "dead blow" the carrier to prevent bolt bounce. It has a secondary function of adding to reciprocating mass and slowing carrier velocity. This issue has come up a few times where the bolt isn't being locked back but it doesn't appear to be a short stroke. Its my guess that the buffer/bcg elastically impacts the receiver extension, sending the carrier forward faster than it would be otherwise and the bolt passes the bolt catch before the mag follower pushes it up enough.

A heavier buffer will slow the carrier down and the heavier spring will absorb more energy.

It would seem to me a heavier buffer would make it short stroke no?

[MovinMan]

Ahhhhh.......that makes sense.

So the BCG is bouncing off the the buffer when the spring is compressed too fast and the bolt catch doesnt have time to pop up and grab it before its slammed back forward.

Sounds right to me.

I would imagine a slower cycling system is easier on parts and felt recoil anyways....as long as it operates properly.

[davidjinks]

OP

You said that when you took the enhanced bolt out the problem went away, right?

But when you put it back in, the problem came back?

If that's the case, I would stop using the enhanced bolt and go with a standard bolt. I believe C4 already stated this. Going to a heavier buffer and spring may prolong the solution to the problem.

[J Krammes]

OK, help me understand this real quick.

An H3 buffer is the heaviest right? So wouldnt a heavier buffer cause it to short stroke...... exacerbating the problem? Or does a heavy buffer add to reciprocating mass and allow the bolt to travel further back against the buffer spring?

In your situation an H3 should not cause a short stroke. It will keep the bolt closed a bit longer allowing the pressure to drop a bit before unlocking (dwell time). With an SBR and suppressor you are dumping alot of gas into the gun making the BCG most likely out run the mag spring. The H3 will slow down the carrier speed too. I had to go to an H3 in my 10.5" AR for a similar issue. I have not tryed the blue spring yet. I will eventually go to an A5.

Jk

[MovinMan]

OP

You said that when you took the enhanced bolt out the problem went away, right?

But when you put it back in, the problem came back?

If that's the case, I would stop using the enhanced bolt and go with a standard bolt. I believe C4 already stated this. Going to a heavier buffer and spring may prolong the solution to the problem.

Actually, I think I am going to do both, lose the bolt and switch to an H3. I want to heaviest buffer I can use without short stroking it anyways.

Again, thanks for the feedback guys.