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Discussion Starter · #1 ·
Well I finely got a chance to go to the range & it's not good at all.

First off I shot my Ar15 & it ate every thing I fed it, about 40 rounds but only 2 hits on the 100 yard target.

Not a problem with the gun, it's my eyes have gone south. I tried using my 2 set of reading glasses,but I just need to put a scope on it & be done with it!

Now the BIG problem, I had 5 rounds of factory 308 & shot that them with no problems. But when I tried my hand loads the first 2 shot fine, but the next one stuck in the chamber!

I got the stuck round out by putting the op rod lever on the end of the shooting bench & giving a gentle push. I had this happen twice more, Then I got a chance to police my brass & it looks like this M1A's chamber is a little tight compared to my old one.

My old one would eat this ammo like it was candy, the new one shows signs of high pressure. time to pull some bullets & start over with the hand loads!

BTW:

I have the same problem with the M1A as I do with the Ar 15, I can't see poop!
 

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I hate to hear you're having issues with your M-14 but you might think about getting a set of small base dies. Have you recently rebarrelled your rifle? What's the head space like and does the chamber look nice and slick? Will a factory 7.62x51 NATO round chamber and easily eject in it?

I recently had cataracts removed from both of my eyes and I now have 20/20 vision. It's the best money I've ever spent. I've been wearing glasses since my early 40s and I'm now 68 and my eyes are back to the point I can clearly see the front sight on my 1911's. Which definitely wasn't the case before the eye surgery.

7th
 

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Yep, small base size die is what you want AND work up another load, as you suspected. Now on the other hand, if you can't even see poop, you're pretty much out of luck! GI2
 

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Your hand loads, what bullet weight, powder grains and what type of powder, brass?

Take Seventh Fleet suggestion by buying a small base die.
 

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Discussion Starter · #5 ·
Gang,

I don't have any factory ammo left, just had the 5 that I shot today & they worked fine.

Rifle has less then 100 rounds trough it, it has to be my hand loads.

Lake city brass
39gr of IMR 3031
168 Match king
C.O.L. 2.800

Shot this load in my other M1A with no problems, just tried 10 of them today & 2 of them stuck, going to pull them apart & reused the bullets, haven't decided if I'll reused the brass. leaning towards trashing the brass

Going to back off to 37Gr's & get a set of small base dies, also a go/ no go gauge.

Also I have about 100 rounds of Federal 308 Brass to try.
 

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Might be a dumb question, but when you resized the brass did you use full length dies or just resize the necks?
 

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Discussion Starter · #7 ·
Might be a dumb question, but when you resized the brass did you use full length dies or just resize the necks?
I used a full length die, it an old Lee set that I bought for my first pre-ban M1a, I never had a problem with the rifle & the same ammo.
 

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If I'm right, 39 gr of IMR 3031 would put the chamber pressure at just about 47,000 psi and your velocity somewhere around 2550 fps. If I was right about the velocity then backing the charge weight down to 37 gr would probably put the pressure at only about 40,000 psi and the muzzle velocity will probably be about 2450 fps. I would be concerned with having too light of a load using the 37 gr charge weight.

I think that somehow combustion gases are leaking out of the system somewhere. Either you have a loose gas plug or an improperly sized cartridge case or maybe something along the op rod path is rubbing and slowing the recoil system down. The gas plug is easy, just make sure that it's tight and not cross threaded. As for something slowing the system down, the only thing you can do is work the system by hand and look for rub points, taking the op rod spring out can help get a feel for any unusual friction points.

Then there is a possibility that the cases are being sized too long at the shoulder and the bolt is not going in to full battery. That would allow some of the gases to escape in to the receiver which would reduce the amount of gas available to operate the system. Do you have the equipment for measuring the head space dimension in your chamber and on the case itself? If so then compare the two. Make sure that the case is at least 3 thousandths of an inch shorter at the shoulder datum line than the measured head space of your chamber. If you don't have the equipment to measure the head space dimensions then you can always try an alternative way of verifying that the resizing die is set properly and that it is pushing the case's shoulder to where it needs to be.

  • Remove the receiver/barrel from the stock and disassemble the rifle so that you can remove the bolt.
  • Strip the bolt and put it back in (don't put the op rod in and leave the stock off).
  • Size your case and then insert it in to the chamber.
  • Attempt to close the bolt by pushing it forward with your finger (you shouldn't have to use much finger pressure, the bolt should almost fall in to place).
  • Verify that the bolt roller goes all the way down on to the receiver rail (if the roller is off the rail, even a hair, then the case is too long and the bolt isn't going fully in to battery).

If the bolt didn't close all the way then turn your sizing die down a hair, resize the case again and follow the same procedure. Do this until the bolt roller touches the receiver rail. That should get your case head spaced pretty close to what it needs to be. It might not be the way a bona fide gunsmith would recommend doing it but it works well enough to prove that the bolt can close properly on the resized case. Hopefully this will get things to function.
 

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Your reloads are fine. It's more likely a tight chamber as you said.

Things you can do, first is to check it. If you confirm that it is tight, then your choices are:

a) Small base die
b) Polish chamber
c) finish ream again & polish
 

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I'll go against the grain and say your chamber is probably not the issue. Is it possible that you are short-stroking due to gas leakage, then driving the empty right back into the chamber? Or maybe the ejector plunger is hanging up, also causing the bolt to drive the empty back into the chamber? With my FAL I had weak performance while adjusting my gas system, and it would do just that.

It just seems so unlikely that a chamber would be reamed short. And how would that cause signs of high pressure? What are these signs of high pressure you speak of?
 

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When the casings failed to extract, was the bolt still attached to the spent case, or did it "lose it's grip" and go all the way back, and then try to feed another round?
 

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Discussion Starter · #12 · (Edited)
When the casings failed to extract, was the bolt still attached to the spent case, or did it "lose it's grip" and go all the way back, and then try to feed another round?

Copterdoc,

As I said in my first post I had to use the corner of the bench to operate the op rod by pushing the the butt of the rifle.

The case was in the chamber with the bolt still attached.

I loaded a few new rounds (38.5gr 3031 in commercial brass) to try out & found one that had pushed the shoulder back just a little, checked some of the ones that had stuck in the chamber & found 2 more that I didn't fire.

Also found 3 spent cases that stuck had the slight bulge at the shoulder, I think that was the problem. I didn't see these at the range.

Next range session I double check before firing & see how it go's, I guess it's time for a go-no go gauge & a new set of dies!

The high pressure sign was the primer was starting to flatten out & the firing pin mark in the primer was more pronounced then the ones on the factory ammo.
 

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If I saw flattened primers I'd be more inclined to suspect long headspace more than short headspace. With long headspace the firing pin sends the cartridge forward as far as it can go against the extractor, then the powder ignites, shoving the primer partially out of the pocket against the bolt face, then the case stretches to fill the chamber so the head comes back and mashes the primer. For tight chambers I don't think you'd see flattened primers. I think you'd see failure to go fully into battery.

I also think that if you had sticky extraction due to a rough chamber or small chamber you'd rip off the rim, tear off the head, or the extractor would jump off the rim. Unless your rims are showing signs of trauma you may want to check whether your bolt is driving an empty back into the chamber
 

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Are you trimming the resized cases?
Agree, If your cases too long, then the rounds may be being jammed into the back of the rifling, especially if your weapon has a chamber that's on the short side. Check the length on your cases and make sure that when you're crimping the bullet that the case isn't being deformed to the point where it becomes too tight to fit the chamber.

Once up on a time I had problems with .45acp rounds that wouldn't chamber in my Series 70 Colt due to the crimp not being tight enough. I was over belling the case mouths to keep from shaving lead while seating the bullets and the crimp wasn't quite enough to return the necks of the cases to where they'd chamber properly.

What I did was to remove the barrel from the pistol and try each one of the reloads individually, to ensure that they'd chamber properly in the weapon. Those were keepers, the ones that wouldn't were run partially back through the sizing die, with the decapping rod removed from the die. This process shrunk the loaded cases back to the correct dimensions.

The point of this being, there may be an issue with your reloaded rounds and the technique you're using.

You need to get some NATO spec 7.62 ammo and see if it will chamber correctly. If so, then you'll know if your reloading techniques are at fault and not your rifle. Just because your reloads worked in your old rifle doesn't mean that your new rifle with possibly a tighter chamber will be as forgiving when it comes to chambering them.

7th
 

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Big Maico,

You enumerated all the spec on you ammo, but I don't see any on the brass length. Just make sure you trim to spec. Brass kissing the throat will spike the presure and if too long, may prevent you from chambering, which is a good thing. My personal choice for length is 2.00, shorter than most would recommend
 

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Discussion Starter · #17 ·
Big Maico,

You enumerated all the spec on you ammo, but I don't see any on the brass length. Just make sure you trim to spec. Brass kissing the throat will spike the presure and if too long, may prevent you from chambering, which is a good thing. My personal choice for length is 2.00, shorter than most would recommend

The brass was trimmed to 2.005 per several of my reloading manuals.

The commercial brass I have is trimmed to 2.00
 

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Factory .308 Winchester rounds functioned fine.

Get some factory 7.62 Nato and see if they function fine also. I'm guessing that they will.

Get a Wilson case gauge for .308. Do the factory 7.62 Nato rounds drop in and check out OK? (they will) Do your handloads drop in and check out OK? If not, then you KNOW the problem is with your sizing die and/or process.
 

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Discussion Starter · #19 ·
Factory .308 Winchester rounds functioned fine.

Get some factory 7.62 Nato and see if they function fine also. I'm guessing that they will.

Get a Wilson case gauge for .308. Do the factory 7.62 Nato rounds drop in and check out OK? (they will) Do your handloads drop in and check out OK? If not, then you KNOW the problem is with your sizing die and/or process.
That my Friend is exactly my plan, it's just going to take a little time, have to order the Wilson die & the Nato ammo, besides it going to be in the mid 30 for the next few days in Houston! not fun to shoot in while your sinuses are killing you!
 
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