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one of us |
I have a Remington 760 which has had misfires since I got it. The gun will misfire on both factory and full length resized loads about 50% of the time leaving very light and shallow primer dents. I found out from the previous owner that both he and the owner before him have had problems with misfires. I have had it to two different gunsmiths who have not been able to correct the problem. So, I decided to experiment. I fireformed (cream of wheat method) 10 pieces of brass. I then neck sized and loaded standard velocity loads. All of these fired with good looking primer dents. I can't see anything visually wrong with the fireromed brass compared to full lengh resized brass. Neither of the gunsmiths checked the chamber with a no-go gauge, so am I correct to I assume there is a problem with either the barrel chambering or with the action itself? If this is the case, what would you guys do? I reload, so if the chamber was opened up to for instance an Akley, etc., this would not be a problem. I really like the rifle and I have a rule against trading off a firearm I know is defective. What would you guys do? | ||
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<Mike Dettorre> |
I think you want to try to determine if the chamber has ever been re-worked or the gun was ever modified. If it hasn't and you want it fixed, send it to Remington they will probably fix it for free. Another oprion is to oredr a new firing pin firing pin spring and replace and see if that solves. Otherwise just enck size and shoot it. ------------------ The sole purpose of a rifle is to please its owner | ||
Moderator |
A quick and dirty way of checking headspace is to put a piece of masking tape on the base of a new unfired cartridge and see if the bolt will close on it with light pressure. The reason is that masking tape is .006" , which is the difference in length for a no go guage. Like the other people, I suggest checking firing pin protrusion too. A way of doing that would be to put a blob of hot glue on the end of a wooden dowel, then when it has cooled put it down the barrel and gently give it a tap. Now you can compare this to the dents made in the brass. It does sound like a long chamber to me too if you are getting satisfactory ignition with neck sized ammo. | |||
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Moderator |
Not that it matters much, but what caliber is it? I'm just wondering if the reason the smiths didn't check is because they may not have that particular no-go guage. Not a reason though to do half a job IMHO. | |||
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one of us |
Very easy fix sell it to some one you do not like. | |||
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one of us |
Thanks for the input. Mark, it's a 30-06. The reason the headspace wasn't checked was due to the missing firing pin spring. The smith was sure that was the problem. Anyhow, I spoke to the previous owner who said something interesting. This rifle has a sling that uses the "ball detent" swivel. These are the ones that you push in a button in the middle of the swivel and it releases. He said he had a problem with the front one letting go which would cause the rifle to fall to the ground striking the front sight. If I picture this correctly, he was holding the sling while it was over his shoulder, the top swivel let go, and the rifle rotated back hard and hit the ground. So, I disassembled and checked how the barrel/mount and frame meet. Much to my surprise, when I pushed on the end of the barrel forcing it onto the frame, I could see daylight between the mount block and the frame. Maybe the barrel mount got bent when the sling let go. If it is bent, this may explain why my headspace got a little too big since the barrel isn't sitting tight against the frame. I'll probably shim it and try it. Also, does anyone know how much of a gap there should be between the action bar lock and the action bar? This rifle has about 1/8" which seems excessive, but I can't find a spec. Thanks. | |||
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one of us |
OK, so I checked the headspace with the tape method. I was able to put two layers (about .010") on the case head and still get the round to chamber. Does anyone familiar with the 760 know how much clearance there should be between the bolt and the end of the bolt stop? It seems like I have way more than I should. This could explain the problem. Thanks. | |||
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<Eric> |
Bir_R, Sounds like excessive headspace. That would explain the misfires, but I would think that it would be apparent with the appearance of the fired case. Sometimes the bolt will pick up the round and the extractor will hold the round enough for a good strike, sometimes not. I'd pack it of to the manufacturer, after I gave them a call to explain the problem and get the shipping address. They may give you a return number also. Regards, Eric ------------------ | ||
<Kerry.S> |
get some cerro safe make a cast of the chamber then mic it. Or sell it. I had a similar problem with an AR 15 that had a bad firing pin. And remember that on most cartridges the diferance between a go and no go is only .004" and a field gauge is around .004" also. So some guy "polishing" the chamber could very easly lengthen the head space. If you are only hunting north American game Then neck size only and call it good. Kerry | ||
one of us |
First, I would not sell a gun that I knew was not in working order to some unsuspecting individual.... What I think from your description is that the chamber is just a tad long and the firing pin pushes the round forward and lessens the indention...It can be fixed by taking a turn on the barrel and a touch with the reamer by rechambering. or send it back to Rem and make them re-barrel it...You can just neck size and correct that situation but in a pump thats not really a good idea as it will jam soon... ------------------ | |||
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