M14 uniting question

84wh1

84wh1

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Hey guys,

My m14 required shimming and because I didn't remove the flash hider, I cut the shim for installation. I did the trick and Si tighten things up a bit but I feel like it's more of a short term temp job.anyways, I wanted to unitize the gas cylinder as it seems like a more permanent fix. If I unitize this beast, does that replace shimming or can shimming still be required?
 
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Unitizing and shimming do different things. Unitizing ensures that there isn't relative movement between the front band and the gas cylinder so that shot-to-shot consistency is maintained. Shimming ensures a tight fore-and-aft fit between the gas lock and the gas cylinder system.

You are right that shimming is a short-term solution. My shims lasted about 600-800 rounds before disintegrating. Only found out after driving myself nuts tweaking my load only to strip down the rifle and find the shims had gone. Ended up buying and trying a number of gas locks until I found one that timed correctly. I also had my gas system unitized but not for the shimming issue.
 
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manuglock17 said:
what do you mean by "unitize" i'm new with the M14

I bought shims but haven't installed it yet
Click to expand...

welding the front "band" to the gas cylinder, thereby "unitizing" it into a solid piece. Makes for less variation due to vibration harmonics from shot to shot, or so I'm told.
 
yup, good answers on the unitizing above ;)

I don't use shims and instead set the barrel on an anvil and roll peen the barrels gas band shoulder, rolling the edge forward. Kinda a job for someone who knows exactly what to do.... but it is dead simple
roll peen the shoulder forward and as you go, test fit the cylinder and gas lock to 4:30 hand tight, tool tight at 6
then ensure a 1/16 drill rod from the bottom hole to make sure the gas port is aligned (drill rod will pass thru into barrel)
remove everything and then I peen in the top splineway so the gas cylinder must be seated with a rubber mallet or hammer and block of hardwood.
reassemble everything and yer good to go.
 
45ACPKING said:
yup, good answers on the unitizing above ;)

I don't use shims and instead set the barrel on an anvil and roll peen the barrels gas band shoulder, rolling the edge forward. Kinda a job for someone who knows exactly what to do.... but it is dead simple
roll peen the shoulder forward and as you go, test fit the cylinder and gas lock to 4:30 hand tight, tool tight at 6
then ensure a 1/16 drill rod from the bottom hole to make sure the gas port is aligned (drill rod will pass thru into barrel)
remove everything and then I peen in the top splineway so the gas cylinder must be seated with a rubber mallet or hammer and block of hardwood.
reassemble everything and yer good to go.
Click to expand...

So this is instead of shimming? Do you still unitize the gas cylinder?
 
Unitizing can be done in such a way that shims are integrated in the unitizing process.
You just assemble the parts on the barrel and put the shims between the gas cylinder and the front band. Then tighten the gas cylinder lock so it's nice and straight, or even almost nice and straight. (you can fine fit it later)
Then you tack weld the front band to the gas cylinder using a TIG welder. This will weld the metal shim in place, so you can forget it's even there.
Loosen off the gas cylinder lock, remove from the barrel and weld the rest so that you don't mess up the tacks.

Make sure the person doing the welding is no back yard hack! If you do it well, it will fit perfectly when done. Just don't over heat it and you'll be just fine.
 
BadAsMo said:
Unitizing can be done in such a way that shims are integrated in the unitizing process.
You just assemble the parts on the barrel and put the shims between the gas cylinder and the front band. Then tighten the gas cylinder lock so it's nice and straight, or even almost nice and straight. (you can fine fit it later)
Then you tack weld the front band to the gas cylinder using a TIG welder. This will weld the metal shim in place, so you can forget it's even there.
Loosen off the gas cylinder lock, remove from the barrel and weld the rest so that you don't mess up the tacks.

Make sure the person doing the welding is no back yard hack! If you do it well, it will fit perfectly when done. Just don't over heat it and you'll be just fine.
Click to expand...

I don't recommend doing that at all. In fact I've repaired rifles done in such a manner.
The shim acts like a fulcrum once under stock pressure at the barrel band lip. Flexing the band forward, even once welded. Eventually cracking the welds at the shim.

This is not a recommended nor advised method and I'd suggest just doing it right or not at all.
Doing it right with shims (or roll peening the gas barrels gas band shoulder) and unitizing means having several gas locks on hand to get the correct gas lock tension and port alignment.
 
How about sanding down one side of the gas cylinder lock to change the engagement of the threads to change the tightening up 'clock'?
 
Nope, that will change internal volume of the gas system ever so slightly and is not a recognized method either. Correcting an over spec(thicker) gas lock by facing it off in a mill is the only time altering gas lock thickness would ever be done.... Or try an in spec thickness gas lock.
 
rb2 said:
Where can one find extra gas locks?
Click to expand...

Norinco gas locks are hard to find (spares)....

I buy my M1A gas cylinder locks from Brownells. When I travelled out west, the TSE M14 clinic in particular, we had 3 x M1A rifles there and all of them were locked nice and tight by hand testing and swapping all 10 or 12 of my extra locks on their M1A barrels (with american thread pattern).

Hope this helps!

Cheers, :wave:

Barney
 
Thanks Barney, I should have specified Norinco. Was at your clinic at GUBs in Kelowna and couldn't get a lock to fit just right. So we shimmed. Really wanna find that sweet one. Cheers, Ron
 
Bull SHHHt!!!

I get the impression that 45ACPKING is a my way or the highway kinda guy. Any suggestion that does not conform to his way of doing things is always challenged like he knows best and everyone else is a twit.
Try getting out of the box dude.

It can be done right and without any fulcrum issues.
You just weld in the right places and do not melt your tacks when doing it.

I've done it several times and mine have all been perfect.


45ACPKING said:
I don't recommend doing that at all. In fact I've repaired rifles done in such a manner.
The shim acts like a fulcrum once under stock pressure at the barrel band lip. Flexing the band forward, even once welded. Eventually cracking the welds at the shim.

This is not a recommended nor advised method and I'd suggest just doing it right or not at all.
Doing it right with shims (or roll peening the gas barrels gas band shoulder) and unitizing means having several gas locks on hand to get the correct gas lock tension and port alignment.
Click to expand...
 
I don't care how "you" do it.
I learned how to unitize about a decade or so ago by strictly following those who have gone before, those who have written extensive works on smithing and accurizing these rifles. Jerry kuhnhaussen, scott duff and many more. So really , what you call "my way or the highway" isn't really "my way" at all.
I've learned by judisciously studying and practicing the works and writings of the most respected M14 gurus in the modern world and some that have passed on. So when you see me saying "do it right or not at all" , I'm not referring to "my way", I'm referring to the ways of the true experts in this field. Do I consider myself one of those experts? No , not in any league with the kuhnhaussen's, duffs, browns, lupinos, fischers ect ect.... But I'm a damn good study.

You can feel free to call me out on my advice anytime you want ;) I've got thousands of hands on hours working on these rifles and will call it like I see it.

Edit: don't take my advice as the gospel, I have no need for the "guru" status that is often thrown around in the accolades that guys like Tactical Teacher and myself have received here and elsewhere over the years.
Here----> is the best advice you will ever receive from me, and you can "take it to the bank" as they say. ---> you wanna work on your m14 and get it right? Buy and study the 30 cal service rifle shop manual by jerry kuhnhaussen. (For the M1 Garand and M14)
That is all.....
 
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I had the shim welded on the gas cylinder. Unitizing improved groupings and I like that I don't have to take care of this small piece when dissembling the rifle. I didn't know this was not recommended? I've had no problem so far.
 
Dake21 said:
I had the shim welded on the gas cylinder. Unitizing improved groupings and I like that I don't have to take care of this small piece when dissembling the rifle. I didn't know this was not recommended? I've had no problem so far.
Click to expand...

That's good that whatever was done is working for you.
I don't care how guys go about modding their rifles, inside the box or outside. What I care about... For some dumb reason that escapes me and keeps me posting is... Bad advice from folks that leads others to screw up their rifles LOL

I'm not trying to be an ass here, I'm merely passing on what I've learned over the years and hope to help save others from some of the mistakes, pit falls and plain ol waste of time stuff that I experienced along my journey.
Having professionaly unitized 100's of chinese and american made assemblies and tuning/repairing/accurizing/custom building a few hundred M14 type rifles from norinco to LRB ect.... We looked for solutions to common issues that the platform, regardless of manufacturer, suffered.

Gas port alignment and the fact that norinco gas locks aren't availlable meant doing away with shims, thus roll peening the gas band shoulder for custom fit.... To many, this IS an out of the box solution to the need for shims.
Then, knowing if we sent a guy his fresly unitized assembly.... He would probably need to shim.
So what did we do, we looked again for a solution. A full shim, kinda tear drop shaped with 2 holes, just llike the gas band. Designed to go between cylinder and band, and providing as much surface area contact. Yes, this did work, but it was fugly and we went back to the standard and accepted method of unitizing, coupled with roll peening that shoulder forward.
Why mess with a good thing right?
 
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