Gas gun won’t cycle

[Tangodown]

Hello,  need some troubleshooting 

Finally got out to shoot my new 6mm ARC build

First test was to adjust the Seekins adjustable gas block.

I followed direction from Seekins:  start with adjustment screw 1 turn off all the way in.  Shoot 1 round only in magazine.  Repeat until rifle will lock back on empty magazine…..

1st shot didn’t eject 
Adjusted 1/2 turn

2nd, 3rd, 4th and 5th wouldn’t eject each with additional 1/2 turn.

6th through 12 ejected but still not enough to lock back……ran out of adjustment.

I’m running a rifle length buffer tube, spring and rifle buffer 5.4 oz

Proof research 18” barrel with rifle +1 gas tube

What to try next? Lighter buffer?

[grayfox]

Couple of suggestions from my end...
Some gas blocks are dimensioned to sit right at the gas block shoulder, some are designed to have that little gap -- so you've verified that your gas block is properly positioned? Usually the GB gas hole is big enough to accommodate some back/forth slop but it's good anyway to know yours is positioned centered over the barrels' gas port.
Some barrels will have a tight chamber, and some early 6Arcs were known to stick some rounds of factory in them, have you verified that your OAL setup in the chamber/bullet/cartridge is not jamming into lands, that it is not too tight...

Ok so next, for any new rifle I start with full open for 25-50 rounds, just so all the pieces have a chance to work together and get rid of any new-stiffness, before I do any adjusting. I've had some new builds that needed that as a break in period. Most of it was a 1-shot and eject or whatever. After break in they cycled fine.

Next, and others may have different views, but I like the carbine style butt stock and buffers and buffer weights. I've had couple of rifle length builds and they just don't seem to cycle as well as they should, but it all resolved after switching to carbine butt stock setup. Just seems like that 5.x ounce rifle buffer is too heavy or something.

I wouldn't think that a proof research barrel had a too-small of a gas port, so I'd leave that out of the equation, at least for now.

[Tangodown]

I just stopped at LGS and picked up a carbine buffer tube, spring and a 3oz carbine buffer

I have an H and H2 carbine buffer in my parts supply.

The rifle was built with a rifle tube, spring and rifle 5.4oz buffer

Gonna swap out and try again

[Dino11]

I had to remove four of the steel weights in a rifle buffer and replace them with aluminum ones I fabricated, and also had to run a 10% reduced power buffer spring to get a rifle setup to cycle. But it is a very soft shooter, and the gas block is almost closed so not much gas going back to to the BCG. Almost zero recoil, It runs clean as well.

[Diesel Pro]

What weight bullets are you shooting?


My specs

Cobalt Kinetics SPR elite
22" Proof rifle plus 1
VLTOR A5 anti tilt buffer with #2 weight
VLTOR also uses a longer tube

I had issues in cold weather shooting 87 vmax so CK sent me a 0 and 1 weights. The 0 took care of the issue for me I now run hand loaded 90 ELDX and am back to the #2 buffer. Will see what happens when it gets cold again.

I did find this disclaimer on the Proof web page:

* 6 ARC Disclaimer - It is our recommendation to refrain from shooting bullets that weigh less than 100 grains.

[Tangodown]

I’m shooting Factory Hornady 108 match

[300BLK]

just a note for anyone desiring to use a rifle buttstock, you CAN use a carbine spring and any of the carbine buffers IF you put a spacer inside the rifle tube so the interal length is the same as the carbine tube

[Tangodown]

just a note for anyone desiring to use a rifle buttstock, you CAN use a carbine spring and any of the carbine buffers IF you put a spacer inside the rifle tube so the interal length is the same as the carbine tube

I just ordered the Spikes Tactical spacer

i I have carbine springs and a variety of carbine buffers.

I checked the gas block and it’s all lined up.   Going to the range this week and give carbine buffers a try.

[grayfox]

Good idea, try some combo's. I had one pesky AR that wouldn't cycle even with the spacer, carbine buffer and spring, in an MBA rifle stock... wound up swapping that one over to a bolt action, and all the semi's are carbine now.
Whatever will work for ya... there's a combo or 2 out there.

[Tangodown]

Well…….Standard carbine buffer tube, spring, and carbine buffer did the trick

Adjusted gas block a bit and it cycled perfectly


I didn’t even bother testing the H1, and H2 buffers

[Kathil]

Somewhat off topic, but is the proof barrel dimpled for a bolt on agb, or do you have to use the clamp on?

[grayfox]

you can always use a bolt on, dimpled or not... measure twice, torque once (so to speak lol!).
I've done it on both types, no clamp ons.
The set screws will make their own mark for your future reference.

[Tangodown]

Somewhat off topic, but is the proof barrel dimpled for a bolt on agb, or do you have to use the clamp on?

it’s dimpled