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Gas Port:
It is also a good idea to check the gas port for both obstruction and alignment. If it's plugged, you will be plagued with short stroking or feeding problems.

Pull the op-rod back and lock the bolt to the rear. Tilt the muzzle up until you hear the gas piston slide all the way back. Invert the rifle and lay it in your lap or in a cradle. Insert a 1/16" allen wrench into the hole at the bottom of the gas cylinder. Wiggle it around until you feel it go inside the gas port hole and gently stick it in as far as it will go. BE CAREFUL NOT TO LET THE BOLT STOP DISENGAGE!!! IF SO, THE OP-ROD WILL FLY HOME AND YOU CAN DAMAGE YOUR PISTON AND GAS CYLINDER ASSEMBLY!!! Now that I think about it, it would really stink if your allen wrench sheared and you had half an allen wrench stuck in your barrel. I use a cleaning port to eliminate the risk. You can also throw a block of wood in the action to keep damage from occuring. If you don't want to take that risk, then remove the gas plug and remove your gas piston.
A trick I use to prevent the op-rod and bolt from accidentally being release while doing the above, or even just while I'm cleaning the bore, etc. is to use an empty stripper clip... slide it in with the bolt locked back, then release then bolt so that it's stopped by the clip... it won't budge after that! I had a bolt slam shut on my fingers before, that's when I figured this trick out...
 

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Checks

The best health care check I can think of , other than what has been covered, is the cleaning of the chamber itself. Lots of people think that if they clean the bore, that the rifle is GTG.

Every M14 owner should invest in and have handy,
A Chamber Brush
A Multi-Tool
A Bore Light
A Dental Mirror
Copper Solvent


In addition to this number one pet peeve, the greasing of the op rod spring should not be neglected. Everytime the op rod cycles, it is rubbing and banging around on the springs external surfaces.

Not just gobs of grease, but a very fine film on the outside. I get some on my finger and rub a little all around where the travel of the rod will be. This will get all gummed up from gasses in the op rod hollow and needs cleaning regularly. I use a wooden dowel with a rag around it and some solvent, then Break free CLR and wipe. For those that do not have a hole in the end of the op-rod it will not gum up as fast, but stills needs maintenance.

I helped a guy fix his rifle the other day, and when I looked in the op-rod hollow, I found dried up grass, or what we call in the horse business, Hay,...all wadded up in the far end. Don't ask me how it got there, I have no idea, but his op-rod was filthy inside, and wear marks very prominent on his spring.

Lastly, the care and cleaning of the magazine. Of the last two listed, this is the third number one thing I see neglected. All that grease and gasses get heated up and get in and on the mags. Self explanatory, disassemble and clean and "LIGHTLY "oil the inside and spring, too much oil could cause primer to not detonate from long term storage mags that are kept loaded.

Good Idea Tony ! Good Post Dozier, A new one on me!
 

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Loose Mag and Failure to Feed

Looking back on it I had several problems with my SOCOM 16. Little by little I resolved them and got it running very nicely but there was one problem that Tonyben has asked me to comment about.

Actually the problem presented itself as several symptoms. The first being that any magazine that I used would fit very loosely in the magazine well, in fact they were so loose that sometimes they would fall out of the rifle while I was shooting. The second symptom was intermittent feeding problems. Sometimes the bolt would not strip a cartridge off the top of the magazine when it would go forward and other times the bolt would jam in to the top of a case and deform it.

I looked things over and I realized that there was something wrong with the op rod spring guide. Early on I noticed that the spring guide would not move. Normally when the bolt is in battery you can reach up in to the mag well and push the spring guide against the op rod spring pressure, mine wouldn't move at all. The part of the guide that protrudes in to the mag well inserts in to the square opening on the front of the magazine and the magazine is held in place by the guide and the op rod spring pressure.

After comparing dimensions against my other rifle, I found that the connector was not in the same location. The one on the SOCOM was about 0.025" or so closer to the body of the receiver (the bottom of the slot that the spring guide sits in).



This created a situation where the op rod spring guide was being pinched between the connector and the bottom of the slot that the guide sits in. This prevented the spring guide from moving far enough in to the mag well and as a result my mags were very loose. To fix the problem I used a hand file to take off a couple of thousandths from the bottom of the slot that the spring guide sits in. The slot on the guide that the connector goes in to is large enough that when I took some metal off the slot the guide had enough clearance to move where it needed to go. I didn't take very much off but I found you had to do this slowly and carefully because just a couple of thousands made a big difference. The original slot appeared to have a slight angle to it and so I attempted to recreate that same angle, and it seems that I was successful because now my mags are nice and tight and I have no malfunctions.
 

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Discussion Starter · #24 ·
Stock Dimensions and doubling/inadvertent full auto...

I just realized that there was something else missing in this thread...

If the thickness of the stock between the bottom surface of the receiver heel and the top surface of the rear portion of the trigger guard is too far, then the rifle may double or go full auto.

Here are the specs taken from a quote from Gus Fisher:

"....Also, on this stock, the distance between the top of the stock and the two supports for the rear of the trigger housing were too far apart. That causes doubles, triples and even unintentional full auto firing in worst cases. A REAL GOTCHA when glass bedding is to have this measurement off. The G.I. measurement is from 1.700" to 1.725". This stock was well over 1.740" and would have been even worse after glass bedding if I hadn't checked it and glassed the rear of the trigger housing with a little distance between the stock supports and housing. I had to inlet the two supports up a bit to shorten this distance and ENSURE the rear of the trigger housing was down right on top of the supports when I bedded the trigger housing and all came out well.

On a couple of LRB receivers I've glassed, the geometry of the receiver was off so I had to reduce this distance even more so the rifle wouldn't double, triple or go full auto. I had to go down to 1.690" on one and 1.685" on another.

If one doesn't realize this distance can cause functioning problems and is so important to safe operation, this can cause real problems."
 

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Discussion Starter · #26 ·
Tried to follow Tilt test but the link ends up dead ????
Here you go...

[ame]http://www.youtube.com/watch?v=l8JcgLh4PI4&feature=plcp[/ame]
 

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Thanks Tony. Everything I have learned about M1A maintenance I have learned from your material.
 
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Discussion Starter · #29 ·
Here's a good one I have never seen from Gus in another thread...

One HUGE thing many people never think about is oil or grease that gets thrown back between the stock and receiver. The receiver hydroplanes on that just like car tires do it on a road when the rain first starts and the dust/mud makes a slurry until it gets washed off.

If there is oil or grease between the stock and receiver, then it should be wiped off very thoroughly.
 

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I think...

I think tonyben needs an official Thread! Stickeys at the very least! I refer to them all the time it would be great to have instant access!
Great job AGAIN tonyben!!!!
 
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Discussion Starter · #32 ·
Forward mounted scope rail

I just thought of another one I didn't see in the previous posts.

There are some M1A scout owners that experience cycling issues who have the forward barrel-mounted scope rail. This barrel can frequently rub on the operating rod during cycling and interfere with proper function. You can either file some off the rail edges where the impact is happening or just remove the rail entirely.

Tony.
 

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Discussion Starter · #33 ·
Well, it's been about a year since anyone dug up this thread from the archives. I figured I'd resurrect it for the new members.

Lots of useful information in this thread by lots of knowledgeable members.

Enjoy!

Tony.
 

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Discussion Starter · #34 ·
I just skimmed through this thread again and I didn't see anything about checking for a loose operating rod guide. Although I did mention that the operating rod and the gas cylinder should be aligned, I didn't mention to check that the operating rod guide is tight or not.

Grab the operating rod guide and try to wiggle it from side to side. If there is play, then the operating rod will hit the piston in different locations from shot to shot.

To fix this, have the barrel knurled and re-seat the operating rod guide on the barrel and epoxy it in place. Make sure the op-rod guide is aligned with the gas cylinder and piston tail before the epoxy sets.

Tony.
 

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OK, this is all good information. But it assumes the reader has some of

the basic knowledge to understand what's being talked about.

I'm still new to the M1A, absolutely love it, but get lost in some of the

terminology, abbreviations, etc.

IE: what the heck is a "ferrule"?

Please don't laugh too hard at me, I'm confessing my ignorance in

hopes I can receive some 'gentle' education. I can figure out what's

being talked about most of the time, but that always leaves a little

bit of doubt. Is there a guide for the absolutely M14 ignorant showing

pics of stuff like a ferrule, sight hood, etc. Seems pretty stupid to

the more experienced, but some of us learn better off pictures.
 

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I just skimmed through this thread again and I didn't see anything about checking for a loose operating rod guide. Although I did mention that the operating rod and the gas cylinder should be aligned, I didn't mention to check that the operating rod guide is tight or not.

Grab the operating rod guide and try to wiggle it from side to side. If there is play, then the operating rod will hit the piston in different locations from shot to shot.

To fix this, have the barrel knurled and re-seat the operating rod guide on the barrel and epoxy it in place. Make sure the op-rod guide is aligned with the gas cylinder and piston tail before the epoxy sets.

Tony.
What about the clearance between the op rod guide and the op rod? I'm a machinist and was wondering (and I'm sure this has been either tried or thought of) if a guy could press in a bronze bushing in the guide, polish up the op rod some, and tighten up the clearance between the two. Any real benefit there?
 

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Discussion Starter · #38 ·
I just realized that there was something else missing in this thread...

If the thickness of the stock between the bottom surface of the receiver heel and the top surface of the rear portion of the trigger guard is too far, then the rifle may double or go full auto.

Here are the specs taken from a quote from Gus Fisher:

"....Also, on this stock, the distance between the top of the stock and the two supports for the rear of the trigger housing were too far apart. That causes doubles, triples and even unintentional full auto firing in worst cases. A REAL GOTCHA when glass bedding is to have this measurement off. The G.I. measurement is from 1.700" to 1.725". This stock was well over 1.740" and would have been even worse after glass bedding if I hadn't checked it and glassed the rear of the trigger housing with a little distance between the stock supports and housing. I had to inlet the two supports up a bit to shorten this distance and ENSURE the rear of the trigger housing was down right on top of the supports when I bedded the trigger housing and all came out well.

On a couple of LRB receivers I've glassed, the geometry of the receiver was off so I had to reduce this distance even more so the rifle wouldn't double, triple or go full auto. I had to go down to 1.690" on one and 1.685" on another.

If one doesn't realize this distance can cause functioning problems and is so important to safe operation, this can cause real problems."
Someone asked me to post a picture of where the stock needs to be relieved to remedy this situation.

The surfaces that must be relieved are the areas of the stock where the tang of the trigger group housing contacts the stock. In the picture below, it's the grey bedding area that HAS NOT been routed. The routed cutout is simply to allow the trigger to be pulled. If that cutout is not there, you can't pull the trigger.

Tony.
 

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Discussion Starter · #39 ·
Here's a couple of new ones....

Action binding after installing a Sadlak NM spring guide

If you've installed a Sadlak NM spring guide and are getting binding when cycling the action, the inner diameter of the operating rod shank may be on the low end of spec (still within, but on the low end). Here's a quote from a member (rifle21) with blueprints...

The inner diameter of the op rod spring passage is shown on the prints as .474 plus .008. In other words the minimum diameter is .474 and the maximum is .482. The spring itself should measure .4575 plus or minus .0025. outer diameter. Hope this helps, and Best wishes to you!
Some M1A owners use a wooden dowel with sand paper wrapped around it and run it inside the shank to open things up a bit.

Gas cylinder fit over the barrel

Even if your gas cylinder is shimmed, there may be some play on the gas cylinder where it fits over the barrel. With the rifle assembled, grab your gas cylinder and try to wiggle it in a rotating manner. If you hear clicking, the barrel can be peened inside one of the spline cutouts to tighten things up. If it's loose, it may or may not effect accuracy.

Tony.
 

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Discussion Starter · #40 ·
I just realized that there was something else missing in this thread...

If the thickness of the stock between the bottom surface of the receiver heel and the top surface of the rear portion of the trigger guard is too far, then the rifle may double or go full auto.

Here are the specs taken from a quote from Gus Fisher:

"....Also, on this stock, the distance between the top of the stock and the two supports for the rear of the trigger housing were too far apart. That causes doubles, triples and even unintentional full auto firing in worst cases. A REAL GOTCHA when glass bedding is to have this measurement off. The G.I. measurement is from 1.700" to 1.725". This stock was well over 1.740" and would have been even worse after glass bedding if I hadn't checked it and glassed the rear of the trigger housing with a little distance between the stock supports and housing. I had to inlet the two supports up a bit to shorten this distance and ENSURE the rear of the trigger housing was down right on top of the supports when I bedded the trigger housing and all came out well.

On a couple of LRB receivers I've glassed, the geometry of the receiver was off so I had to reduce this distance even more so the rifle wouldn't double, triple or go full auto. I had to go down to 1.690" on one and 1.685" on another.

If one doesn't realize this distance can cause functioning problems and is so important to safe operation, this can cause real problems."
Quoting my own post to add pictures...

The sample stock seems to run a little on the short side. Also, it's hard to get an accurate measurement for this, I placed the lower caliper on the contact point and looked over the top of the stock until the upper caliper was even with the top plane of the receiver.

Tony.
 
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