Gas block alignment tool??? Cycling issues.

Patt08

Patt08

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Trying to locate a gas block alignment tool for my AR. Anyone know of where these can be found or if they can be sent from the states?

Ive done the compressed air method, and line with a pencil. Reason im looking for the tool is because im having cycling issues and want to know 100% for sure if a misaligned block is the issue or not.
 
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Didn't even know such a thing existed.

If it looks right and you've got flow through it, it's not likely to be the problem.
 
Patt08 said:
Yeah that's what I'm thinking. I've installed several other gas blocks with no issue ever, but this time I went with an adjustable JP one and can't get the bolt to hold open or eject. Scratching my head.
Click to expand...

I assume you've played around with the settings?
 
Yep. Started completely closed, moved up 1/2 turn 2 times. Load 1 round and shoot, bolt wont hold open so open another 1/4 turn and repeated this process until it was completely open. Same issue.

I removed and re-installed the block several times. Tried PMC 55gr, AE 55gr, Nosler varmageddon 55gr, Hornady superformance 55gr.

I tried a different bolt, different lower.

*Edit* : Should mention that when running the second lower with standard carbine buffer system, TWO rounds out of 10 did eject, but failed to load another round into battery.

Here's what im running:

Aero Precision lower
Rainer Arms ultramatch billet upper, Mod 3
18" McGowen SS match barrel, 1/8 twist with rifle length gas.
JP adjustable gas block
Lantac E-BCG
Trigger Tech adjustable trigger
BCM enhanced lower parts kit
BCM pistol grip
KNS pins
BAD enhanced pin set
BAD enhanced mag release
AXTS raptor ambi charge handle
Lantac Dragon muzzle brake
Noveske NSR 11 handguards
Magpul ACS-L buttstock
Vltor RE-A5 buffer tube
Vltor SP-A5 spring and buffer

Stevo said:
I assume you've played around with the settings?
Click to expand...
 
Patt08 said:
Yep. Started completely closed, moved up 1/2 turn 2 times. Load 1 round and shoot, bolt wont hold open so open another 1/4 turn and repeated this process until it was completely open. Same issue.

I removed and re-installed the block several times. Tried PMC 55gr, AE 55gr, Nosler varmageddon 55gr, Hornady superformance 55gr.

I tried a different bolt, different lower.

*Edit* : Should mention that when running the second lower with standard carbine buffer system, TWO rounds out of 10 did eject, but failed to load another round into battery.
Click to expand...

Is this a new build or have you previously run this barrel with standard gas block?

Are the Vltor spring and buffer heavier than standard?
 
New build. Have not tried a standard gas block.

Vltor buffer is H2 standard 5.3 oz it says.

Tried with a different lower with a milspec buffer system and thats when 2 rounds ejected successfully out of 10 shots.

http s://www.vltor.com/shop/ar/receiver-extensions/re-a5-a5-receiver-extension/

Basically i have everything here listed in this link below, minus the VLTOR stock.

http s://www.vltor.com/shop/ar/stocks/aebk-a5-vltor-a5-stock-combo-kit/




Stevo said:
Is this a new build or have you previously run this barrel with standard gas block?

Are the Vltor spring and buffer heavier than standard?
Click to expand...
 
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I'd give it a try with a regular gas block if you have one. I suppose it's possible the JP is flowing less than it should.

Failing that, as mentioned, it does sound under gassed. I could see it short stroking with the 5.3 oz buffer but it isn't running on the standard carbine buffer either. You could probably get a decent estimation of the gas port size by fitting drill bits.
 
I wanted a clamp on, adjustable and could only find the JP. I actually had to order it from Brownells. I left a tiny space between the gas block and barrel shoulder going to see if that works. Going to have to pick up some feeler gauges and make sure i have the 0.025" gap. Carbon marks around the port hole on my barrel tell me that i was pretty much bang on though.

BigSporkkNasty said:
I went with a suparms adjustable gas block. Used a 0.025" spacer when installing the gas block. Got it dialed in no problem.
Click to expand...
 
Patt08 said:
I wanted a clamp on, adjustable and could only find the JP. I actually had to order it from Brownells. I left a tiny space between the gas block and barrel shoulder going to see if that works. Going to have to pick up some feeler gauges and make sure i have the 0.025" gap. Carbon marks around the port hole on my barrel tell me that i was pretty much bang on though.
Click to expand...

I really doubt that barrel is made for a handguard end cap. Try it right up against the shoulder.
 
Ditch the Adjustable block, just by running a rifle length tube and the Vltor A5 buffer system, your gas pressure should be at the optimal setting, the adjustable block will just restrict the gas flow unless you set it to full at all time and that is just a bit silly.
 
5.3oz buffer is too heavy. My 10.5 barrel wont cycle even with a standard gas block. My guess is that the vltor spring could be XP too.

My seekins adjustable runs at 2 turn from closed on a 16 midlength with 3oz buffer and a RP buffer spring. Std buffer spring is about 3 to 3.5 turn
 
Measure the gas port on the barrel and report back.

If you have a gas issue, start at the source (ammo and gas port) and work back towards the receiver.

Your ammo is good, so check the gas port next.
 
A new, tight chamber and ammo can contribute to hard extraction and therefore cause short stroking as well, so if your gas system is installed properly, start looking beyond it.
 
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