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Discussion Starter · #1 ·
Well, not so good news. chiz45, myself and a bunch of enthusiastic newbies went out to the desert today. We had a great time but the Smith, Ltd. M14 needs some help.

The Smith, Ltd. M14 feeds and ejects without a hitch but has difficulty cycling. The bolt cycles smoothly by hand without a magazine in the rifle. When the rifle is shot the bolt comes back far enough for the right hand lug to make the jump up to the rail then it stops. Then it is difficult to pull the bolt back to extract the spent case. The bolt holds on to the spent casing then ejects perfectly once the case clears the chamber. We did not notice any unusual marks on the cases. We shot it six times then decided to ask for some guidance. The barrel is a mint condition USGI National Match Canadian Arsenals barrel. The bolt is TRW and head spaces at 1.632". The spindle valve was "on" allowing gas to flow from the barrel to the gas cylinder for all six shots. We used 1978 Portugese surplus which my select fire M1A can't get enough of.

Any ideas as to why the bolt will only partially pull the case to the rear? The only thing I can think of is a very tight chamber.
 

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Good call on that one, If it were me, I would give it some time and some more ammo to settle in. I forgot did you have the rifle refinnished if so try a chamber brush and give that a few extra strokes as well this can`t hurt ether, come to think of it I would do this first then some more ammo. Best of luck to you :D
 

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Aloha Different:

Did the brass have any signs of a tight chamber? Scratches on the brass, etc. I would say go easy on the polishing of the chamber. If it is too tight, it might be better to have it reamed again or finished reamed... as a thought. A glass smooth chamber could cause the round to "fly" into the chamber and crimp the neck of the round into the end of the chamber which would NOT be a good thing when shooting!

Take Care and Good Luck! Tell Chiz we said "Hello"!

Aloha,

Tom O.
 

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Hello Dighawaii:

Another thing to check is the firing pin.Check the side of the firing pin and see if it is hitting the bridge on the receiver.If it is just file down the side of the firing pin untill it clears.

Your brass will tell ya everything about the chamber,A scratch could be from a burr,case neck area or out of round chamber,etc. If headspace is 1.632 then it's not tight.

Op-rod bent ? :roll: Try another to find out.
Op-rod spring guide bent??
Op-rod spring weak??
Gas port lined up and clean?? (could cause short cycling)
Gas cylinder plug clean?? (could cause short cycling)
Here's a good one-op-rod guide on barrel at 6 o clock and tight?? I had this problem before.
Of course this is only a partial list.
HTH
Gotta tell us what is was when ya find out though.

I forgot this one.Is op-rod jumping the track on the receiver??
I've done so much work on M14's and M1A's that it's hard to remember everything untill I have too fix it for someone. :wink:


Fly high,shoot low and you'll hit'em every time.warbird
 

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Discussion Starter · #7 ·
Thanks for all the suggestions. Work has kept me very busy but I finally was able to get out to the desert again with the Smith, Ltd. M14.

The operating rod is not jumping the track. I cleaned the chamber. That helped a lot. I did find the unitized gas cylinder was not seated all the way. So, I corrected that. Using a very thick sewing needle I confirmed that the gas cylinder is lined up with the barrel. The gas piston and gas cylinder plug have no carbon buildup.

I shot forty rounds through the rifle. The rifle did the same thing every time. The bolt moved to the rear but did not go far enough to strip the next round in the magazine to feed. About five or six rounds the spent case did not quite clear the chamber and the bolt stopped it mid-travel. Some of the case mouths were flattend on one side. Could it be the firing pin hitting the receiver bridge? Anyone have any ideas?
 

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Different,
It looks like a lot of ground has been covered as far as what might cause your problem. One thing I have not seen though is gas cylinder piston to gas cylinder fit. Could it possibly be that there is to much clearence between the piston and cylinder allowing to much gas to escape around the gas piston?

Just a thought.

Regards

Ox
 

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it sounds to me that if it is not cycling back far enough to pick up another round That it has to do with either the chamber or the gas system. This may sound a bit silly, but did you check the gas port in the barrel to make sure it is clean? You might also try a different piston and plug to rule them out. Also one way to check the chamber might be to put a little transmission fluid on the round before you shoot it and see if it comes full cycle. Sort of lubing it with a super thin lube. If it cycles then you know it's the chamber. This is an old trick I learned in shooting blanks in the 03. You might also try spraying your chamber brush with brake clean before cleaning the chamber in case it's gummed up a bit. You might want to clean your bolt real good and put some birchwood casey blueing on the lugs to color the wear and see where it is rubbing most. Can't think of anything else at this point. Keep us all posted on what you try and what you find.
 

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Discussion Starter · #11 ·
Thank you, thank you for all the ideas. I have the rifle apart. The bolt is not rubbing the under side of the receiver which I greased as well. I'm going out to the desert now with some spare parts to try them. I'll report back when I return.
 

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Discussion Starter · #12 ·
We just returned from the desert. Still no joy. :cry: The rifle is still doing the same thing. It is not retracting far enough to feed the next round in the magazine.

I am reasonably certain the operating rod guide is in the correct position. I watched Bill at Smith Enterprise install it using their alignment tool. It looked good to him and myself. The TRW operating rod chiz45 picked out for this rifle glides very smoothly in the receiver. I swapped the gas cylinder plug, gas piston, and bolt with USGI ones proven to work in my pre-'94 ban standard model SA, Inc. M1A. I also cleaned the chamber and the barrel again this morning prior to going to the desert.

The cases are much more deformed at the mouth than cases I shot through my pre-'94 ban standard model M1A today. The cases are not ejecting as far as they should. The firing pin is making a good solid dimple on the primers. There is no wear on the side of the firing pin. The operating rod spring measures 15.5" long so that is good. The operating rod spring guide is straighter than an arrow. I have been using USGI M14 magazines and the same magazines work fine in my pre-'94 ban standard model M1A.

At this point I will take the Smith, Ltd. M14 to Smith Enterprise to see what they can find.
 

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Sorry to hear that you're still having difficulties with the Smith Ltd. If all of the externals are working and alligned properly, the bolt has no excessive wear or burrs, and the spring and guide are ok then my feeling is that the the problem is in the barrel chamber. The markings on the front of the casing are most likely either from the casing being ripped from the chamber or from hitting the receiver on the way out during ejection. This I take it is not a Chrome lined barrel? If not the whole thing might be fixed easily by re-reaming the chamber.
 

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Discussion Starter · #14 ·
Hawk7173, that sounds quite possible. The case mouths are getting dinged up from hitting the receiver. This is a non-chrome plated barrel. It is a USGI Canadian Arsenals National Match standard contour 1:12 twist rate barrel. I don't see any unusual wear on either bolt I tried.
 

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When an M14/M1A fires the gas piston only drives the bolt about an inch to the rear. From then on it is inerta that finishes the cycle . I would say that it may not venting enough combustion gas into the piston chamber. Also If the inside forward part of the Barrel/chamber is bigger in diamater or more iregular in shape than the rear, the spent round might stick as it starts moving toward the rear opening of the chamber because the front of the casing would resize (Larger)when the round is fired. This would mean a new barrel. You might try taking a micrometer and see if the forward part of the spent casing is a few thousands larger than the back. Another thing you could try is turning off the gas valve and firing a round. You (or Smith LTD) may find the spent round is having trouble moving even earler in the cycle than expected. This also would lead me to think there is an iregularity in the forward part of the barrel/chamber
...........Just a thought.......SP/4 Twiggy
 

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In my prevous post I should have stated that the chamber mentioned in the first part is the gas piston chamber. The chamber in the second part is the actual chamber for the ammo round.
 

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Discussion Starter · #18 ·
Okay, we have great joy now! :D :D :D First, I cannot sing enough praise about Smith Enterprise. I took the rifle into them at about 1:30 PM on 09/17 and I picked it up the same day at 4:00 PM. They were able to correct the problem. 8)

Bill at Smith Enterprise told me that the M14 barrel gas port is typically 0.076" diameter. Prior to taking the Smith, Ltd. rifle to Smith Enterprise I tried to gently put a 1/16" (0.0625") diameter drill bit in the barrel gas port. It would not fit. Bill told me that the barrel gas port was too small in diameter. He drilled it out to 0.089" diameter then shot it at a nearby range. Problem solved! Bill also told me that this barrel gas port can be drilled out as large as 0.100" diameter if need be and still function properly.

While the rifle was at Smith Enterprise I also had them do a trigger job. It is a very smooth two stage trigger now breaking at 4 1/2 pounds. chiz45 and I tested the Smith, Ltd. rifle at the Las Vegas shoot this afternoon. It worked just fine. :D Now, chiz45 needs to sight it in. :wink:
 

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Very cool that you got the problem resolved. I'd never have thought the gas port on the barrel would be drilled incorrectly. Goood info to know, thanks!
 

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Discussion Starter · #20 · (Edited)
P. S. On June 11, 2006, chiz45 and I (yes, I was in Las Vegas) sighted in Smith, Ltd. serial number 0237 at 25 meters. There was a shooting match going on at the rifle range of Desert Sportsmen Club so we could not test it any distance.

chiz45 left me a message yesterday. He took Smith, Ltd. serial number 0237 back to the range. He adjusted his elevation appropriately and hit the steel gong at 400 yards with iron sights three out of three times. All's well that ends well. GI6
 
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