AR Pistol Rapid Fire Lag

[newbieLA]

Thought I'd post this here since it's an AR platform

New Build Specs:
Franklin Armory CA7 Lower
DD MK18 complete upper
Geissele Super 42 spring + H2 Buffer
Geissele SSA-e 2 stage trigger


First time at the range with this setup and fired 200 rounds, cycled flawlessly with no failures.

However when I was rapid firing I noticed several times my finger would go to reset and pull the trigger a millisecond before the trigger had reset. If I slowed my self down a fraction of a second there was no issue. However this is slightly slower than the rhythm I'm used when rapid firing my other AR-15s.

So the question:

1) Is this a spring or buffer issue?

or

2) Does the AR - Pistol just need more rounds to "break in" and loosen up?

[caliguy93]

Sounds like the bcg is moving a bit slow probably due to the heavy buffer and super spring.. not much you can or should do without swapping the buffer, spring, and bcg as even standard milspec buffet and springs will do that.

Less friction on the bcg and different buffer/spring setups may get your action cycling faster.. some say going to a carbine length gas system may help too since it’s a shorter distance for the gas to travel but i doubt its be noticeable given how fast that stuff is already moving

[enorbit3]

What weight is the buffer it comes with from the factory? Have you tried that one yet?

[newbieLA]

Thanks for the reply. It's possible a few hundred more rounds will wear in the parts enough to reduce friction in the BCG.

I also think the H2 buffer is pretty standard for a 10.3" upper so I'm leaning towards the spring as a possible swap out, question is do I go heavier or lighter?

What weight is the buffer it comes with from the factory? Have you tried that one yet?

I have not, but I will be taking the stock spring and buffer with me to the range next week and test them both out to see if there's a notable difference.


Look forward to any other suggestions folks may have. Thanks!

[enorbit3]

Oh and Caliguy. The mk18 upper is already carbine length

https://danieldefense.com/mk18-upper-receiver-group.html

[dousan]

Might try a springco blue with an H2. Ive read very good feedback on that.

I use a g h3 setup but mine is all suppressed. No feeling of a trigger lag. On a urgi 10.3 from geissele.

Also what kind of ammo you using?

[newbieLA]

Might try a springco blue with an H2. Ive read very good feedback on that.

I use a g h3 setup but mine is all suppressed. No feeling of a trigger lag. On a urgi 10.3 from geissele.

Also what kind of ammo you using?

I'm using Fiocchi & Federal XM193 5.56. again it all cycled flawlessly without any failures, but the minor trigger lag was annoying. Surprisingly the Geissele Super 42 is supposed to be "super" stiff exactly for these AR Pistol setups.

Thanks for the recommendation on the Springco Blue, Have heard good things about their springs.

[dousan]

Ammo sounds good to me.

I run the g spring on a 12" sbr too, no issues. Super reliable i guess mostly.

Also, are you letting the trigger out enough to reset too? I rarely rapid fire but illl try next time i go out and shoot it. I don't recall any issue unless i didn't get the reset right. Like i pull and pull too soon by not letting it out enough. Usually after a few shots id do that. Since i don't shoot as such normally my finger n brain arent trained/ in sync


I think you can also remove a tungsten weight in your buffer, see if it as a h1 works better. Just put in a rubber guy to replace the removed one, of course.

[newbieLA]

Ammo sounds good to me.

I run the g spring on a 12" sbr too, no issues. Super reliable i guess mostly.

Also, are you letting the trigger out enough to reset too? I rarely rapid fire but illl try next time i go out and shoot it. I don't recall any issue unless i didn't get the reset right. Like i pull and pull too soon by not letting it out enough. Usually after a few shots id do that. Since i don't shoot as such normally my finger n brain arent trained/ in sync


I think you can also remove a tungsten weight in your buffer, see if it as a h1 works better. Just put in a rubber guy to replace the removed one, of course.

Thank you , All very good observations. I also don't rapid fire often so there is a possibility that the "brain / trigger" sync is slightly off.

Based on your recommendation I did some google searches and ordered the Spinrco Blue ($20). Here's my plan for next week's range trip:

Bring my AR-Pistol and LWRC AR-15 for comparison, both have the same Geissele SSA-e Trigger.

For the AR-Pistol, I will use the following combinations:
1) Geissele Super 42 Spring + H2 Buffer
2) Sprinco Blue Spring + H2 Buffer
3) Stock Spring & Buffer (I believe the stock buffer is H1)

I'll focus on my technique to eliminate "brain/trigger" sync.

I think the above should help address the issue but open to any other thoughts.

Thanks!

[newbieLA]

Update:

Took the AR Pistol back out to the range along with my LWRC SPR as reference.

I compared the Geissele Super 42 spring vs the Sprinco Blue Spring (both with the same H2 Buffer). The Sprinco Blue was far smoother on this setup and Easily rapid fired 5 round bursts at a fast pace. With the Geissele I had to deliberately slow down my trigger speed to prevent a lag when rapid firing.

Thanks again for the recommendation on the Springco Blue!

[FeuerFrei]

The pistol was over sprung and was pushing a heavier than needed buffer weight.
Slower to cycle. No surprise there.

Next time use a white Sprinco spring and a carbine 3oz buffer or an H buffer as a backup.

Anyone reading this and wanting to build/tune a AR pistol should take note.
Adjustable gas block.
White Sprinco spring or equivalent.
3oz buffer weight or an H buffer.

This combo will allow the user to use low pressure Wolf or PMC on up to m193/M855 NATO stuff.

[newbieLA]

The pistol was over sprung and was pushing a heavier than needed buffer weight.
Slower to cycle. No surprise there.

Next time use a white Sprinco spring and a carbine 3oz buffer or an H buffer as a backup.

Anyone reading this and wanting to build/tune a AR pistol should take note.
Adjustable gas block.
White Sprinco spring or equivalent.
3oz buffer weight or an H buffer.

This combo will allow the user to use low pressure Wolf or PMC on up to m193/M855 NATO stuff.

Good to know, I'll pick up a White as well to compare. BTW the White sprinco is rated for 300 blackout as well right?

[dousan]

Nice!!! Great to hear was better!!!!

[FeuerFrei]

Good to know, I'll pick up a White as well to compare. BTW the White sprinco is rated for 300 blackout as well right?

It's equal to mil spec carbine action spring. I swapped over to Sprinco years ago and I do have different colors (spring rates) and used them for troubleshooting. Good stuff.

https://www.sprinco.com/tactical.html

IIRC the 300 uses subsonic or supersonic. The ammo swap can change things.

Generally speaking most will run fine on a white spring/carbine stock/3oz buffer.
Obviously there are always variables like gas port sizes that can cause inconsistent operation with a variety of loads.

[Mr. Blue]

I tried to read this, but with that signature I could not. I had to quote you to read it fully.