Armory Sponsor
Posted: 6/3/2010 3:03:13 PM EDT
|
Alright guys now I have another question ? first off I have got (2) loads I am working with and today was the second outing so here is the boring stuff:
LC Cases (Milsurp) 5 reloads Shoulder bumped to 1.628"-1.629" (Dillon F/L Sizer) Trimmed to 2.006"-2.007" WLR Primers Nosler 168 CC seated to 2.810"/2.235" (I acutally measure off ogive) 40.0gr and 42.0gr IMR 4895 Rifle benched at 100yrds STD SA M1A Tupperware Stock Sadlak Spring guide and coated gas piston On my last outing I had pretty decent groups about 2"-4", these were from loads ranging from 38.0-42.0 in .5 increments and the 40/42 did the best (about 2") so I wanted to duplicate it before trying to vary anymore on the load, well today I went out and fired in groups of (10) and they were all over, I fired (2) sets of 10 at 40/42 and they were drifting down and to the left and were avg about 4" Well after going thru the 40 rnds and coming home I was trying to figure out what happened and as I started to clean I found my gas plug loose and backed out about (2) turns, so I have to ask would the loose plug affect groups ? and if so how, I know the gas piston drives back the op rod which is attached to the bolt (M1A's are new to me, only had this for about a year and just starting reloads for it) The band that spins around and lines up in front of the gas block goes about a 1/8" past so I have to back it off the threads that 1/8" to get it lined up to drop in the piston and thread in the plug. |
|
Yes, a loose gas plug will affect your rifle's accuracy. It needs to be tighten to a specific torque setting (and I don't remember the exact tightness). Use a torque wrench to get it set correctly.
I had this happen to me in the past. My torque wrench is set for this procedure, and it's at 7 Foot/pounds. But it's not terribly accurate at its lower settings. |
|
Snug without being too tight.
The threads are very fine and will not survive any abuse on the users part. You can use a sharpie or white out after it's tight, so a simple look see will confirm that it hasn't backed out. Consistency is important, match rifles are built so that no stress is being applied when the bolt is tight. Aftermarket shims are available to accomplish the same thing. Most of us don't have a bucket of parts to sort through until they find the one that "just fits". 
|
|
Quoted:
I think you should use something low, like 15 to 25 INCH pounds. That's one or two foot pounds. Just snug. I have found several that recommend 10ft lbs ? And then I found this from Glen Zediker "Al Baker, former Marine Corps Armorer, recommends setting the gas plug torque to 20-ft.lbs. That’s not a “magic” number; the 20-ft.lb. figure resulted from the Corp’s need to arrive at a constant they could use for every rifle. They found 20-ft.lbs. high enough to keep the plug from coming loose but not so high as to crack it." |
|
I don't have mine set that high. I don't use a torque wrench either, even though I have one. A firm snugness without throwing your body weight into the wrench. I use a gas cylinder wrench and a either a craftsman box end wrench or the M14 combo tool. Hand tighten the plug and put the wrench tool on so that it's near the gc wrench and basically grab both the box end wrench and gc wrench and pull the two closer. Wrench movement at the tip is less than an inch or about a 20 degree arc.
If I was really serious I'd use the torque wrench and paint a stripe on the gas cylinder lock and plug so that when installed correctly the painted line parts line up again. And 41-41.5 grains is just about perfect in my M14 clones. ETA- I've never had a loose plug in my M1a but my garands with old worn polished gas plugs do have a tendency to loosen if not watched. Accuracy will not just fall off, it'll go for a running dive off a cliff holding an anvil. |
|
It's never come loose before and since I am trying to work up a load having the plug loose most likely did not help when I went to the range, I am also thinking of shimming the gas system, first it's inexpensive and second it's not permanent
It looks like I can do it without pulling off the flash hider by cutting the shim at a 45 angle and slipping it behind so I can get the band tighter currently it goes slightly past the 12:00 position so I have to pull it back to get it to line up for the plug, if I can use a split the shim what positon do I want the band in when it gets tight |
|
Try to imagine what's happening with the M1A gas cylinder. Ideally you want it tight without applying any stress to the other parts. If there is a gap when you tighten the gas plug it's going to torque on the barrel up top. I try to shim mine flush. No pressures either way. This may or may not have any effect on target but it makes good sense to me.
It won't hurt anything if you put one drop of Loctite 222 on the gas plug. Make sure it doesn't run inside where the piston lives. This will give you more security in the field that you aren't coming undone during a match and won't interfere with your ability to remove it anytime you want. Loctite 222 is the weakest on the market. It's designed for very small bolts that must be disassembled without using heat. As far as 20 foot pounds of torque, I would double check that article for a typo. The threads on the gas plug are very fine. I think 20 foot pounds may be able to strip them. If not, it will be very close to doing so. Twenty-five years ago you could pick these parts up anywhere. Gun shows had tables full of M-14 and M1 Garand parts, many of them brand new in government packaging. They were cheap too. Nowadays they are getting harder and harder to find, and cheap never crosses my mind. It's a shame they didn't continue with the M-14 as a Designated Marksman rifle. Continued new production and parts at a modest 1000 to 2000 new rifles a year. 25 to 30 years from now nobody will want to shoot them for fear of lost value, wear and tear and breakage. I believe it's impossible for the armed services to think "small". If they had maintained this platform and replenished old stocks they would have had a completely different set of circumstances in the mountains and deserts of the middle east. Nobody would be complaining about lack of long range capabilities. |
|
Quoted:
Try to imagine what's happening with the M1A gas cylinder. Ideally you want it tight without applying any stress to the other parts. If there is a gap when you tighten the gas plug it's going to torque on the barrel up top. I try to shim mine flush. No pressures either way. This may or may not have any effect on target but it makes good sense to me. It won't hurt anything if you put one drop of Loctite 222 on the gas plug. Make sure it doesn't run inside where the piston lives. This will give you more security in the field that you aren't coming undone during a match and won't interfere with your ability to remove it anytime you want. Loctite 222 is the weakest on the market. It's designed for very small bolts that must be disassembled without using heat. As far as 20 foot pounds of torque, I would double check that article for a typo. The threads on the gas plug are very fine. I think 20 foot pounds may be able to strip them. If not, it will be very close to doing so. Twenty-five years ago you could pick these parts up anywhere. Gun shows had tables full of M-14 and M1 Garand parts, many of them brand new in government packaging. They were cheap too. Nowadays they are getting harder and harder to find, and cheap never crosses my mind. It's a shame they didn't continue with the M-14 as a Designated Marksman rifle. Continued new production and parts at a modest 1000 to 2000 new rifles a year. 25 to 30 years from now nobody will want to shoot them for fear of lost value, wear and tear and breakage. I believe it's impossible for the armed services to think "small". If they had maintained this platform and replenished old stocks they would have had a completely different set of circumstances in the mountains and deserts of the middle east. Nobody would be complaining about lack of long range capabilities. Well I loosened my gas plug and was able to move the band to about the 1:00 or 7:00 position and it stops and won't budge so I have to back off to get the plug in, i checked port alignment with a small allen wrench and it seems to drop thru to the barrel so if I shim it how far forward will it push the GC as my concern would be port alignment and how long will the shims last ? I think it's the 7:00 position, with the rifle inverted (GC up) the GC band threads on fine but when it get tight and can go anymore it's about 1" past lining up or what I would call 7:00 so I have to turn it back to get it to line up As far as torque I found this and it does not seem that high: If you are using a torque wrench, the minimum recommended torque is 120 inch pounds (10 foot pounds) and the maximum is approximately 23 foot pounds. The popular ranges are 120 inch pounds to 150 inch pounds. Gas plug torque may affect accuracy so play around with what torque works best in your rifle. German torque is also acceptable (Good-N-Tight) |
|
panther - Use an automotive feeler gage to establish what size shim you need. When it's lined up perfectly to accept the gas plug what size feeler gage will just slip between there?
The shim should last forever, nothing is going on that will reduce it's life. If it creates any problems (I don't see how it could) simply remove the shim and revert to the original confirguration. "Ideally" the gas lock should get tight just before, or right at, alignment so the system isn't torqueing anything. The shims will make it happen without resorting to a box full of parts until you find the ones "that just fit". Make sure you visit the M1 - M1A board which is in the Armory section also. A lot of long time M1A shooters visit there. |
|
Quoted:
panther - Use an automotive feeler gage to establish what size shim you need. When it's lined up perfectly to accept the gas plug what size feeler gage will just slip between there? The shim should last forever, nothing is going on that will reduce it's life. If it creates any problems (I don't see how it could) simply remove the shim and revert to the original confirguration. "Ideally" the gas lock should get tight just before, or right at, alignment so the system isn't torqueing anything. The shims will make it happen without resorting to a box full of parts until you find the ones "that just fit". Make sure you visit the M1 - M1A board which is in the Armory section also. A lot of long time M1A shooters visit there. Thanks, now I have to find a shim kit 
|
|
Quoted:
I can't remember where I got my shim kits, either Fulton Armory or Smith Enterprises. I hate to be cheap but Fulton wants $9.95 + $10 for s/h for (3) shims that will fit in an envelope and SEI may take up to 2 weeks to ship and they want $15 not counting s/h so where can I get some shims that dont cost a fortune to ship or is it just the way it is |
|
Update:
I want to thank all you guys for giving advice on how to do this and make it sound simple, well here is the work being done by me and I had no issues at all Here are the shims (.005, .008, .010 and .015) from RAParts along the Castle nut pliers from Brownells and the Sadlak GC wrench 
Set screw backed out without any problem: 
I don't have a vice (live in a apartment) so I had the rifle in my cleaning rig and backed off the nut with just a good steady push 
I was able to thread off the nut and pull the FS by hand without much effort 
Here is what I had before: 
This is what I have after putting in (2) shims totaling .013", before lining it up for the plug to go in I put it back in the stock as someone had suggested doing before putting pressure on the band then the last step was to tighten the gas plug. I had read several recommendations on a torque and went with 135" lbs which seemed to be in the middle of the road, please tell me it that is to much but I compared it to this: [COLOR="Red"]If you are using a torque wrench, the minimum recommended torque is 120 inch pounds (10 foot pounds) and the maximum is approximately 23 foot pounds. The popular ranges are 120 inch pounds to 150 inch pounds. Gas plug torque may affect accuracy so play around with what torque works best in your rifle[/COLOR] 
I checked the piston alignment and it looked good 
I checked port alignment and the hole is alittle more forward than it was before I started but it seems to still drop thru to the barrel. As far as reinstalling the FS goes I know I had a concern about it going on crooked but once I saw it off I knew it would be really hard to get it on crooked as the splines and grooves keep it lined up and it threaded on so easy and then bottomed out. After I snugged up the castle nut and reinstalled the set screw I backed the castle nut against the set screw as suggested (did grease all threads and NO LOCKTITE) I am not sure how much this will help accuracy but from what I have read and been told this is the best upgrade you can do for the minimal amount of money. Once I get some rounds loaded up I want to see what she will do Thanks again for all you advice !! |
|
You installed the shims on the barrel instead of between the locking nut and the gas cylinder? I just slipped mine between the locking nut and the gas cylinder, held them in place so they would'nt fall out and slipped the retaining gas bolt though the locking nut, the shims and into the gas cylinder.
You may have accomplished the same outcome by going the long way around the barn, I don't know. I didn't have to remove the flash hider the way I did mine. How many shims did you end up using? |
|
Quoted:
You installed the shims on the barrel instead of between the locking nut and the gas cylinder? I just slipped mine between the locking nut and the gas cylinder, held them in place so they would'nt fall out and slipped the retaining gas bolt though the locking nut, the shims and into the gas cylinder. You may have accomplished the same outcome by going the long way around the barn, I don't know. I didn't have to remove the flash hider the way I did mine. How many shims did you end up using? I was told by Claude at RAParts along with the instructions enclosed that they go behind the barrel band (22) their is a lip/shoulder on the barrel that the barrel band butts against, I was instructed I could remove the FS and slide it all off along with the GC and put the shims against the shoulder or leave the FS on and cut the shim and slip it over the barrel, I chose to get the pliers and do it right and I used (1) .008" and (1) .005" shims to put it at the 4:30-5:00 position 
Here is a short video of the process but he is cutting the shim due to a welded FS M14 Shimming |
Armory Sponsor