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First off just let me say that yes I am a noob as it pertains to rifle building. My experience so far has been shooting and cleaning only. So if this question seems stupid..... ICONREDFAC
I have read some interesting comments on this forum pertaining to the unitizing of gas cylinders in NM rifles. From what I have read there are at least 2 different ways to do it. The screw and glue method and the welded method which is used by the USMC if I'm correct. If someone could explain the pros and cons of choosing one over another. Is it just which method the armorer happens to have been taught ?
I am collecting parts now for a LRB & USGI build as many of our members probably are.MCORPS1 I was hoping for some insight from a few of the resident experts on our forum as to which method they choose and why. I did do a couple of searches but did not find what I was looking for. Thanks.
 

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If you use the screw method, you wont be able to turn the gas valve to off. Not a big deal, but you should be aware of that. With the weld method the valve will still be operable.

I dont think one is better than the other but Ive only had the weld method done in the past. However, the person doing the welding should know what they are doing. If the gas cylinder has been heat treated, its harder to weld hardened steel (or doesn't "take" to the welding as easily), but it is also harder to drill hardened steel as well, so its a toss-up...

You can, as a 3rd alternative use shim washers to tighten up the play between the barrel front band shoulder, the front band, and the cylinder. I believe Smith does this with their Crazy Horse builds. You can buy the washers from Smith as well...
 

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If you use the screw method, you wont be able to turn the gas valve to off. Not a big deal, but you should be aware of that. With the weld method the valve will still be operable.

I dont think one is better than the other but Ive only had the weld method done in the past. However, the person doing the welding should know what they are doing. If the gas cylinder has been heat treated, its harder to weld hardened steel (or doesn't "take" to the welding as easily), but it is also harder to drill hardened steel as well, so its a toss-up...

You can, as a 3rd alternative use shim washers to tighten up the play between the barrel front band shoulder, the front band, and the cylinder. I believe Smith does this with their Crazy Horse builds. You can buy the washers from Smith as well...
LRB probably used the screw method on my 2009 M25. I was told not to try turning the gas valve.
 

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Like James said I don't think one is better than the other regarding function. Pro's both are tried and true methods.
Pro for welding, still retain function of the spindle valve. Why would this be a benifit? No expert recently brought up a good point, "trouble shooting", it not like we will be launching grenades anytime soon which is why it's there in the first place. You can still single fire the rifle I guess is what he was refering to. Secondly I would say is cost, it's less money to get a system welded. Cons if it cracks from what I gather is rare for us weekend shooter it has to be sent back to get rewelded.
Amtu method pros, you can more than likely fix it yourself if a screw breaks. Although I think you would need a pretty good drill press and have to make up a jig if you had to drill out the screw if it broke off and there was nothing sticking out to grab with a vice grip. I'm tossing this one out there, more armorers know and utilize this method but I am not certian. I use one guy to weld mine and got lucky and found the one who IMHO is da best at it. Somi guess what I'm saying is you have more options where to send it for the amtu method. Cons your spindle valve is rendered inop but as I said before this is really a mute point, we are not launching grenades although it would be interesting to give it a whirl. For whatever reason I bought the grenade attachment I would say from a colletor stand point just so I can have, to quote The late great George Carlin "more usless $h1t" in a box that I will never open except to put more usless stuff in and ocasionally oil. I think it comes down to a matter of personal preferance. I too have both styles on my rifles my sai is screwed and the lrb's are welded. As I opened with there is no differance in functionality. Anyone have anymore thoughts?
 

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Discussion Starter #5 (Edited)
If you use the screw method, you wont be able to turn the gas valve to off. Not a big deal, but you should be aware of that. With the weld method the valve will still be operable.

I dont think one is better than the other but Ive only had the weld method done in the past. However, the person doing the welding should know what they are doing. If the gas cylinder has been heat treated, its harder to weld hardened steel (or doesn't "take" to the welding as easily), but it is also harder to drill hardened steel as well, so its a toss-up...

You can, as a 3rd alternative use shim washers to tighten up the play between the barrel front band shoulder, the front band, and the cylinder. I believe Smith does this with their Crazy Horse builds. You can buy the washers from Smith as well...
jameslawson71and 82ndABN - thanks for your informative replies. This is one of the reasons to love this forum.

I'm going with the USMC welded method for my build. That was what I was already leaning towards anyway just because the Marine way is usually GTG, those guys are the best in my book. Now that I hear the screw method doesn't allow for use of a grenade launcher that settles it.dance2 and if I happened to come across a grenade launcher and ammo in a EOTWAWKI it will still be serviceable with my rifle.
You can send multiple jihadiots to meet allah with one pull of the trigger.MCORPS1
 

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I was told a genuine advantage of the USMC Welded Method was that you can turn off the spindle valve while cleaning the bore, keeping bore cleaner out of the gas system. Perhaps single shot use for load development might be a secondary benefit.

Plus, I like mechanical things that are still visible and in place on anything to actually work. Hated fake hood scoops on cars back in the 1970s! And someone just might try to turn that valve someday - and break the screws! CC
 

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Screws

The only problem I have run into with screwed together gas systems is a very few (very few) that had the screws shoot loose.

These were not staked at all and used allen drive screws that didn't allow much torque during assembly.

Gas systems assembled with Phillips or slotted screws that are epoxied and staked correctly don't shoot loose.

The nice thing about screws is they can be easily retightened if they do get loose. How do you fix a cracked weld in the middle of a match?

In the many thousands of rounds I've put though M14 rifles during my career, I have never had a desire or need to shut of the gas valve and never found it to be an issue with the screwed and glued gas system.

Properly welded gas systems work fine and I have no problem with them, but I prefer and use screwed together unitizing on my personal rifles.
 

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Yes, it'll tighten up the band to the barrel shoulder. The fewer shims you have to use and the less you shoot, the more secure it'll stay for longer. If you want to shoot the rifle frequently and optimize its accuracy, get the front end unitized and it's done.
 

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I like welded because of the ability to operate the spindle valve. But I also agree that a broken weld in the middle of a shooting event is a drag.
 

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Pardon my ignorance on the matter, but couldn't you just buy a NM Gas Cylinder from SAI and install it for the same effect. If this works, it seems like a simple $110 solution as opposed to sending your current unit off.

I'm just getting into accurizing my standard model, so I have been pondering this question.
 

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The only problem I have run into with screwed together gas systems is a very few (very few) that had the screws shoot loose.

These were not staked at all and used allen drive screws that didn't allow much torque during assembly.

Gas systems assembled with Phillips or slotted screws that are epoxied and staked correctly don't shoot loose.

The nice thing about screws is they can be easily retightened if they do get loose. How do you fix a cracked weld in the middle of a match?

In the many thousands of rounds I've put though M14 rifles during my career, I have never had a desire or need to shut of the gas valve and never found it to be an issue with the screwed and glued gas system.

Properly welded gas systems work fine and I have no problem with them, but I prefer and use screwed together unitizing on my personal rifles.
Always a +1 on Ted's comments. I've always preferred the Screwed and Glued method when done properly. Welded units are alright to when Properly done also. I've just never warmed up to the idea of welding on a GC with its tight tolerances. Way to much chance for warpage/cracks than I'd like to think. dozier
 

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Pleading ignorance, but I've been researching issues involving the front band, stock ferrule, gas cylinder and glass bedding recently. It seems to me that an argument can be made that using shims and not unitizing may be the best solution because it allows you optimize the front band // stock ferrule alignment for your action in your stock.

Even if whoever does the unitizing has everything centered and aligned perfectly, your action may not fit in your stock perfectly. Therefore, positioning the front band after mounting the action in the stock might be the best approach.

IIRC one of the experts here (Art?) seemed to be saying that, but I may have misunderstood.
 

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Pleading ignorance, but I've been researching issues involving the front band, stock ferrule, gas cylinder and glass bedding recently. It seems to me that an argument can be made that using shims and not unitizing may be the best solution because it allows you optimize the front band // stock ferrule alignment for your action in your stock.

Even if whoever does the unitizing has everything centered and aligned perfectly, your action may not fit in your stock perfectly. Therefore, positioning the front band after mounting the action in the stock might be the best approach.

IIRC one of the experts here (Art?) seemed to be saying that, but I may have misunderstood.
I must say, that I agree with Tinman, and have no scientific data to back it up except my groups. I have no unitized systems and all my rifles will shoot MOA, so I see no use to do anything different than what I have.
 
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