Gas block alignment tool??? Cycling issues.

Stevo said:
I really doubt that barrel is made for a handguard end cap. Try it right up against the shoulder.
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It is not. Had it custom made from McGowen in the states via a site sponsor. I originally had it right up against the barrel shoulder with zero success. Ive read that it actually could be the JP lo pro block that needs to be more forward but idk. I tried moving it around.

Agent Law said:
Is the E-BCG heavier than a regular one?
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It is 11.70z so not much heavier. I also tried a standard BCG and it made no difference.

sky52 said:
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
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I thought so too possibly. But this is exactly what this system is made for. I tried with a different lower with a milspec carbine spring, buffer tube and standard buffer and the same issues persisted. 2/10 rounds DID extract, but failed to hold the bolt open or feed a new round. Tried different mags, ammo.

*MALICE* said:
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.
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Okay will do. I tried 4 different kinds of ammo, even match grade stuff and the same issues persisted.

beltfed said:
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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There's ZERO extraction. Hell, the bolt barely moved out of the chamber as far as i could see. It moved a tiny bit, so when i pulled the trigger i could just see it click back forward. The bolt slides perfectly around, is lubed nice and wet.
 
One way to check if your GB can run right up against the shoulder of your barrel, is to remove the screw closest to the receiver end, slide the GB all the way to the shoulder but upside down. Visually check and see if the barrel's gas port is fully exposed through the screw hole (clamp on style GBs also have a hole). If it is, you don't need to apply a spacer or set it away from the shoulder.
 
A rifle length gas system on an 18 inch tube could potentially cause a low gas pressure issue unless you're using hot mil spec ammo. (Depending on the maker)

I would try to get a box of xm193 or xm855 and see if it likes the hotter ammo? That would be a good way to check if your gas port is undersized and needs to be opened up a bit for normal pressure ammo!
 
My barrel is strictly .223 rem. This build was done with highest accuracy potential in mind so i cant use the 5.56 stuff. Maybe i could try a way lighter buffer and see what happens. The problem is, the RE-A5 system uses proprietary buffers and springs so I have to find somewhere that sells them, order from brownells, or swap the buffer system out completely.

F22_RaptoR said:
A rifle length gas system on an 18 inch tube could potentially cause a low gas pressure issue unless you're using hot mil spec ammo. (Depending on the maker)

I would try to get a box of xm193 or xm855 and see if it likes the hotter ammo? That would be a good way to check if your gas port is undersized and needs to be opened up a bit for normal pressure ammo!
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Okay. I measured twice and got 0.083" using digital calipers. Give or take 0.001" for human error. The port size seems within the range, idk.

Information i've found online says as follows.

16" barrel , .750" dia, min barrel port : 0.070" max barrel port 0.086"

20" barrel , .750" dia, min barrel port : 0.093" max barrel port 0.096"

barrel port size..jpg

*MALICE* said:
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.
Click to expand...
 

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OldFrankHog said:
Rifle length gas on 18" should be closer to .100".

18" doesn't leave much barrel lenght to build pressure past the port.
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Yep, this is what I was getting at, that gas port would likely function with mil spec pressure ammo, (which is one reason middy is popular with 18" barrels; as they usually cycle both just fine) but not normal .223. So it would appear you likely have an undersized gas port. Even a lighter buffer is only going to be a bandaid fix, if it works at all, but drilling a gas port is pretty easy easy work! I did it with my AR15 barrel, but I had access to a nice mill...
 
I appreciate the feedback guys. It is definitely undergassed then. I emailed McGowen to see what they say. Unfortunately it's not as easy as sending it back to them as it took 9 months to get in the first place lol. I don't have access to a mill either.

F22_RaptoR said:
Yep, this is what I was getting at, that gas port would likely function with mil spec pressure ammo, (which is one reason middy is popular with 18" barrels; as they usually cycle both just fine) but not normal .223. So it would appear you likely have an undersized gas port. Even a lighter buffer is only going to be a bandaid fix, if it works at all, but drilling a gas port is pretty easy easy work! I did it with my AR15 barrel, but I had access to a nice mill...
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Got a reply from McGowen. They say that they drill them all to 0.082" ( pretty much right what I measured) to give end users to open the ports up as needed. They suggested increasing the size in small increments and function testing along the way. I will try getting it opened up to 0.085" as suggested and go from there I guess.
 
Have you done a bolt check ? (gas rings check)

stand the removed bolt ( extended ) on a table (upright locking lugs down)
the weight of the body should not colapse it
 
just having some fun said:
Have you done a bolt check ? (gas rings check)

stand the removed bolt ( extended ) on a table (upright locking lugs down)
the weight of the body should not colapse it
Click to expand...

That's not the correct way to check gas rings.

The correct way is to remove everything but the bolt, hang the BGC in the air, bolt facing down, the bolt shouldn't fall from the BCG on it's own weight if the rings are good. If it falls it needs new rings.
 
Patt08 said:
Checked both my bolts as you mentioned. They are A-OK.
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Well, of course. If your bolt didn't fail the improper test, it can't possibly fail the proper test.

The problem arises when people ditch perfectly good gas rings because they tested them with an incorrect testing method that probably came from a gas ring manufacturer who wanted to sell more gas rings.
 
Patt08 said:
Got a reply from McGowen. They say that they drill them all to 0.082" ( pretty much right what I measured) to give end users to open the ports up as needed. They suggested increasing the size in small increments and function testing along the way. I will try getting it opened up to 0.085" as suggested and go from there I guess.
Click to expand...

Keep in mind, if you open it up a little too much, you already have that nice adjustable gas block to help you out! But as stated most machine shops will be able to do the work fairly easily! It took me all of 10 minutes to drill mine (most of that was setup), and it was nitrided 4150cmv. 1 drill bit to pierce the nitride, and bore half way, then another to break through very slowly to avoid a burr.

The proper specs for 18" barrels are a little hard to come by, but most seem to run (as previously stated) .104 to .110. Even jumping to .085 may not make a difference, but slowly increasing the size is a very safe bet!
 
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