AR15: Switch from carbine length gas assembly to mid length possible?

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xopher

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First of all, I am an AR noob which is why im seeking answers from you more experienced guys.

I just purchased a Stag Arms Model 3 AR15 w/ 16 inch barrel off of EE and im pretty sure it comes with a carbine length gas assembly.

The previous owner had installed a 7 inch Daniel Defense Quad rail and im planning on replacing with something longer in the near future. I am really favouring the look of longer quad rails incomparison to the short one that came with the rifle. Seeing as how im looking to replace the rail, is it possible to change the carbine length gas assembly with a midlength gas assembly? I was doing some research and some people are saying mid length gas assemblies are optimized for 16 inch barrels for smooth shooting.

If the switch is possible, what kind of parts should i be looking into getting for this swap? Is it as easy as getting a longer gas tube and moving up the gas block? The long 16 inch barrel looks like has already been indented for installing a gas block further from the reciever.

Here is a picture of the rifle and the indent on the barrel:

ar009.jpg
 
No, you cannot put a mid length gas assembly on the rifle without switching out the barrel. Reason is that the barrels are tapped for a certain length gas assy. The stepped portion ahead of the gas block is an M203 cutout. If you want to put a longer rail on the firearm, you can get a low profile gas block (maintaining the carbine length gas tube, naturally) and a rail that will go past the gas block. I've always been partial to dissipator builds myself, so if it were me I'd be looking at a rifle length quad rail.
 
That means i have to get a new barrel right?

Well if i want the longer quad rail, i just have to purchase a low profile gas block and swap them right? Im assuming the low profile gas block will tuck nicely under the quad.
 
New barrel, new gas tube, low pro gas block.

Not all low pro gas blocks will fit under all rails... some are larger than others.
 
wow quick responses! thanks guys!

Where so where can i find a rifle length quad rail? Im looking for something free floating but cheaper in terms of price because im on a budget. Ive already sourced a mid one for about 160 but ur right... the full rifle length should look better

Oh and one thing to add. How does the balance feel with the full rifle length quad? Will it make the rifle very front heavy?
 
ATRS has a Midwest Industries 12" quad rail for $250. If you figure around another $75 for an appropriate low profile gas block, shipping and taxes, you'll be a little south of $400. If you're willing to sell your railed gas block and quad rail, you should be able to fund around half of that from the sale of them, maybe more, depending on how much you can get for the DD quad rail.
 
luckily i live in Calgary so i dont need to pay shipping :)

TSE also carries NEA products. I think ill wait for them to get some of the NEA quad rails in stock too.

Soo many choices...

How much do you think the Daniel Defense Quad will sell for?
 
.. We also have mid length 18" barrels and gas tubes as well. Talk to TSE and we'll hook you up.

Better option would be to pick up a complete mid length upper of you're looking for barrel/tube/block/rail.
 
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IMHO If you are not haveing issues with your carbine lenth gas system don't frig with it. Spend your saved barrel cost on the best FF system you can,add lo-pro gas block and run it as is.Lots of good options out there JP,Daniel Defence,Troy,Midwest,AP customs,PRI, ETC...
 
greentips said:
Instead of dismantling a functional rifle, I sugget that you use the money to get a case of ammo.

A case of ammo will probably do more good than pissing the money away on a new barrel or longer handguard. Just my 2 cents YMMV.

Look is a bit useless if the proficiency of the trigger puller does not match the coolness of the tool.
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I agree. Especially being new to the AR, practice will have far reaching effects.

If the bottom line is you want a longer rail, get a low profile gas block and longer rail. There's nothing wrong with the barrel or gas system length.
 
North Eastern Arms said:
.. We also have mid length 18" barrels and gas tubes as well. Talk to TSE and we'll hook you up.

Better option would be to pick up a complete mid length upper of you're looking for barrel/tube/block/rail.
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My $.02 worth, stop making 18" barrels with carbine gas systems and transition completely to mid-length tubes on your 18's. This will make more people happy - trust me.
 
@OP - I don't know much about the AR15 pigtail gas tube but it seems it may be one answer to your question. Maybe some of the AR15 gurus here could chime in.

Here's a description from Brownells:

AR-15/M16 PIGTAIL GAS TUBE

Controls Gas Pressure To Cure Cycling & Feeding Problems For Rifles, Carbines & Handguns

Extra-length tube lengthens the gas pressure curve to help prevent bolt bounce, short-stroke and feeding jams. Helps prevent cycling problems common to carbines and pistols. Slows bolt carrier to improve feeding reliability and reduce wear and battering. Gives softer recoil impulse, decreases cyclic rate in full-auto fire. Fits under free float tubes and handguards. Carbine fits all 10 inch to 16 inch barrels. Pistol fits 7.5 inch barrels only.



More info on the pig tail gas tube can be found by googling "AR15 pig tail gas tube"
 
I have yet to see an AR15 who's problems were solved y those pigtail devices. The more I read about them, the more leery I become. In theory, as they heat up (rapid fire), they flex and the tube could start not lining up with the gas key, thereby making any problem worse.
 
Claven2 said:
I have yet to see an AR15 who's problems were solved y those pigtail devices. The more I read about them, the more leery I become. In theory, as they heat up (rapid fire), they flex and the tube could start not lining up with the gas key, thereby making any problem worse.
Click to expand...

Thanks for the clarification Claven. It was just something I read about at Arf.com. Didn't pay much attention to the thread but it was something that kinda stuck in my mind.:cheers:
 
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