Basketcase Rem700 Help

[cahunter805]

Hey guys. Just looking for any info on this problem. I picked up a rem 700 from a guy and it has either a chamber/bolt problem. The lugs on the bolt were lapped. The high side was lapped about .003 so that both lugs would make decent contact. Now when a round is chambered there is resistance on the bolt. When I eject the shell I noticed a rub mark on the bullet and also the shoulder of the case(handloaded round only neck sized but once fired brass). I am thinking the bolt is not square with the chamber anymore. What options do I have? I know that lapping the other lug a bit might help but was worried about headspace issues then. What do you think?

Here is a pic of the cartridge. Notice the rub on the bullet. I colored it all to tell where it was making contact.

 

[Kenny474]

Maybe try a factory loaded round. If it still does it you know you have a problem.

Also, is the fired brass from the same gun? If you are using once fired brass in a different gun than it was fired in you should full length size it.

I don't think .003" is going to throw a bolt that far out of alignment. I may be wrong, but I think you have a brass issue. Use new brass, or a factory round, and see if the problem goes away.

And it may just be something in the pic, but it looks like the neck is cut.

 

[cahunter805]

The neck is cut because I was measuring the lands. The brass is once fired and neck sized and is from the same gun. I also tried another cartridge that been used in the rifle before the lapping with no problems and that one did the same thing.

 

[Kenny474]

If you are using brass that was formed before you lapped the lugs, than the brass is the problem. You are using brass formed with a bolt that wasn't sitting true. Now the bolt is true, so the brass is going to chamber differently, ie: slightly crooked.

Try new brass, or reform some of the brass you have.

 

[cahunter805]

Thanks Kenny. I was somewhat considering that but was way to late last night and just was over the whole thing. I figured it was something with the shoulder or case. I will try tonight with a factory round and also FL a piece of once fired brass and load a bullet. THANKS

 

[Kenny474]

Update if it helps. I hope it does. If not, I can't imagine what it could be.

 

[cahunter805]

Thanks guys. Got it figured out. Just a brain fart lastnight! Sometime simple things just give you the run around.

 

[TRECustom]

cahunter, I hope you will let us know what you found or did. I'm still going to recommend that you check headspace with a no-go gage. When I've lapped locking lugs, I've never needed more than about a 1/2 mil (.0005") to get the other lug into contact. .003' sounds like way too much. You may be at the very limit of SAAMI headspace. Figure that the factory chamber had go + .002", then if you added .003" by lapping the lugs back, you would be at or over the recommended headspace for a short, shoulder headspaced cartridge. Depending on the cartridge, there will only be between .004" and .006" difference between go and no-go, and if the bolt will close on a no-go gage, the chamber is too long and the rifle should not be fired. It may not be in danger of exploding, but it can do some unpleasant things like leaking gas into the bolt vent system, and will be tough on brass. Measure overall length, diameter of the cartridge .200" in front of the base, and diameter at the shoulder of a new cartridge or new brass, then take the same measurements on the same cartridge or brass after firing. Overall length shouldn't grow more than about .002", the web area shouldn't grow more than .002"-.003", but the shoulder may grow a lot more. If it does, check the fired case against SAAMI case size. A lot of factory ammo, particularly Winchester, will be .005"-.010" smaller in diameter at the shoulder than the SAAMI standard. Makes it chamber real easy.
On the subject of lapping, that should be done with the barrel out of the receiver. Otherwise, it is very difficult to get all the lapping compound cleaned out. Also, a spring-loaded lapping tool should be used. (The barrel has to be out to do this). If you lap by just pulling back on the bolt handle, the pressure on the lugs is assymetrical and can lap the lugs in slightly canted.
Not enough space to cover all the things that can scuff a case, but in general, they are scuffed while feeding, not while extracting. Next time you're at the range, try chambering a round and then extract it without firing and see if it scuffs. Probably will.
Sorry about getting so long-winded on what may not be a problem anymore. Check headspace anyway. It needs to be done.

Good shooting, Tom

 

[cahunter805]

Tom My bad it was only .0003. The problem was the shoulder just needed to be bumped back on the fired cases a few thousandths. I am still going to fire a new factory case this weekend and check the measurements. I knew it had to be something simple. Just was late at night and didnt want to mess with it anymore. Thanks for all the help guys!

 

[TRECustom]

Like you said, the simple stuff gets us with alarming regularity! Who said zero's don't count. I've learned that when I get tired, I need to quit whatever I'm doing if it's critical. I start making mistakes.

Sounds like you're O.K., but taking the unfired and fired dimensions will be instructive anyway.

Good shooting, Tom