Curing the Carbine Length Gas System

[GorillaTactical]

Sure, we (carbine gas system users) can switch to a rifle length gas system...but that costs $$$ as we need to swap our barrel (at least that is how I understand it...I'm by no means cultured in the intricacies of the gas system)...so how about this solution offered by Loki Weapon Systems:

Loki M4 Gas Block

I am considering ordering it to test but figured I'd check with what others had to say first. Maybe one of the Loki guys can chime in with how it works....I've been in contact with Loki CEO J.E. Davis and he assured me this is a drop in replacement with no new modifications necessary. Sounds like a dream solution to the over-gassing problem.

Edited September 24, 2010 by GorillaTactical

[jmurch]

Never used one (my 17" is rifle gas) but I'd presume from reading the maketing literature that the gas port in the block is a smaller diameter.

Jeff

[jmurch]

Never used one (my 17" is rifle gas) but I'd presume from reading the marketing literature that the gas port in the block is a smaller diameter.

Jeff

typo..... and apparantly i cant tell the difference between edit and reply.

Edited September 24, 2010 by jmurch

[caspian guy]

Or maybe there is some kind of manifold/expansion chamber machined into the gas block to let the gas expand and drop the pressure in the gas tube?

If you ever get an explanation let us know what they say...

[GorillaTactical]

Or maybe there is some kind of manifold/expansion chamber machined into the gas block to let the gas expand and drop the pressure in the gas tube?

If you ever get an explanation let us know what they say...

Yall figure this is something worth trying out?

[Graham Smith]

I'm not sure if it would work better than an adjustable gas block, which is less expensive.

[jmurch]

I would go for the adjustable since you can tune it to the loads that you want to use............

Jeff

[GorillaTactical]

I would go for the adjustable since you can tune it to the loads that you want to use............

Jeff

Would the adjustable on a carbine length system still be more effective? I've heard that it can't be dialed down enough to really feel anything like a rifle length gas system. That's why I was exploring this option in the first place.......and as a follow up...are the JP blocks drop in replacements for the stock block?

[smokshwn]

Call Loki and talk with JE.....IIRC there gas block does not simply impinge the gas impulse like and adjustable gas block but rather retards the peak pressure (manifold I think) to ease the pressure spike.

Although you can put an adjustable gas block on a carbine and get some reduction in recoil impulse the gas is still at a higher peak pressure at that point in the barrel. To be the most effective you need to reduce the peak pressure not just impinge it.

[GorillaTactical]

Call Loki and talk with JE.....IIRC there gas block does not simply impinge the gas impulse like and adjustable gas block but rather retards the peak pressure (manifold I think) to ease the pressure spike.

Although you can put an adjustable gas block on a carbine and get some reduction in recoil impulse the gas is still at a higher peak pressure at that point in the barrel. To be the most effective you need to reduce the peak pressure not just impinge it.

That is what I thought hence why I figured I'd go with this one. I did speak with JE, he does a good job selling his prodcut

[Graham Smith]

That is what I thought hence why I figured I'd go with this one. I did speak with JE, he does a good job selling his prodcut

Give it a try and let us know how it works.

[caspian guy]

Before I bought one I would want to know how it is supposed to work. That way I could evaluate the claims made vs the mechanism by which they are supposed to be achieved so I can see if they seem reasonable.

[GorillaTactical]

Spoke with JE today...these are out of stock for the next month

I'm gonna try a JP adjustable for now and get this when it gets back in stock.

[Kevin J]

I wonder if they are available in steel vs. aluminum.

[Huck]

A pigtail is the only cure for a carbine gas system. M`16 clinic makes them and they do work. Adjustable gas blocks don't do much. New barrels work wonders! :D

[Big Bore]

I took a Benelli mercury recoil reducer and packed it tight in a a2 butt stock. It helped with the feel of the recoil.

Then I got a new barrel.

[Supermoto]

A pigtail is the only cure for a carbine gas system. M`16 clinic makes them and they do work. Adjustable gas blocks don't do much. New barrels work wonders! :D

This is what I have found also. I have a 14.5" that was over gassed. The rifle was trying to unlock while the pressure was to high, leaving the the case in the chamber. Increasing the tension of the extractor helped with the extraction but the gun was very violent. I added an adjustable gas block, which did little to smooth the rifle. I recently added a pigtail gas tube, this combined with the adjustable gas block smoothed out the rifle considerably. Unfortunately the gas block cracked before I was able to put significant rounds down range. But today I will try a standard gas block and see how the rifle feels compare to the adjustable gas block

Update: with a standard gas block the gun is not as smooth as with an adjustable gas block, but definitely smoother than with the carbine gas tube. The rifle is more enjoyable to shoot, so the cost of the pigtail was worth it for me. Now I think my 14.5" rifle was particularly violent. I recently shot a 14.5" firebird that was much nicer. I'll have to compare these two later this week

Edited October 5, 2010 by Supermoto

[GorillaTactical]

A pigtail is the only cure for a carbine gas system. M`16 clinic makes them and they do work. Adjustable gas blocks don't do much. New barrels work wonders! :D

The JP actually works wonders in mine. I use their BCG LMOS as well so maybe that has something to do with it....but with my Titan Brake, JP carrier and Gas Block, and a standard carbine buffer hollowed out, My reticle does not move vertically AT ALL...I am very pleased with the new gas block...

But either way.......why would a pigtail be any more effective than what I highlighted in the original post??

Edited October 6, 2010 by GorillaTactical

[djeffers]

I put a miculek comp and buffer technologies hydraulic buffer in my 16" and it worked wonders. If I was not already on a new build I would have probably tried the big tail and/or an adj. Gas block......but at this point I was very satisfied with the first two mods.

[Supermoto]

So I found how to cure the carbine impulse on my rifle. To expand on my earlier post

I have a 14.5" Remsport barrel that was so over gassed that it would leave cases in the chamber. The gas port is about .098. When I installed a adjustable gas block and turned it almost all the way, Even though the rifle did smooth out some, the over pressured gas ate through the gas block. The erosion was happening with both the standard gas tube and pigtail.

I sent the gas block to the manufacturer (Firebird) for them to look at. Jim went over what had happened and why, then offered to replace the gas block free of charge even though it was not defective or a design issue.

He spent a good amount of time going over gas port size, recoil impulse and gas tube length.(It was a real education.) I realized that I was never going to be able to get this barrel to shoot the way I wanted it to, no matter what bandaid fix I did, it was just to over gassed. So I ended up getting a barrel from Firebird.

When the barrel arrived, the difference in the gas port size was immediate. I installed the barrel today with a SJC titan and got a chance to function fire it today. It is very smooth and soft. I'm very happy with the result.

I ended up spending a lot more on the remsport barrel and all the things I have tried to get it to run right then I spent on the Firebird barrel with a matching bolt and gas block.

Edited October 25, 2010 by Supermoto