Steve Nash
New member
Why not get someone to stick the barrel in a lathe and just polish the chamber with some 400 wet & dry...I have had the odd barrel with a ring or two that polished out nicely...You have nothing to lose.
Steve
Steve
Stiff Bolt Part 2. Pics up!!
- Thread starter skeetlee
- Start date
Looking at your brass I see what appears to be a big shiny ring right at and immediately below the case wall shoulder junction. Looks to me like some chips may have accumulated and went around with the reamer and gouged out a grove at the chamber shoulder a bit larger in diameter than the chamber wall below the shoulder. When it is fired with a lower charge, I think you mentioned it extracted easier, the case may not be expanding entirely into this ring and extracts easier than a higher charge. With a little heavier charge, dosen't have to be a hot charge, just one heavy enough to make the brass swell far enough into the chamber ring that it could be locking the case into the chamber, when you lift the bolt and it starts to cam over to begin extraction you could be in effect sizing down this possible ridge on the brass in order for it to be extracted. This could explain the bright ring right at the body shoulder junction. If this is whats happening then it easily explains your bolt lift resistance. Try a charge of 26 grains and see if it extracts easier than a 29 grain charge, that should give you a pretty good indication if this could possibly be the problem.
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K
kindwolf
Guest
skeetlee,
If you ignore the fact that it's a rifle and try to analyse it from a purely engineering viewpoint, as Jerry Sharret says, the marks cannot be made by a reloading die as that would always leave striations along the length of the case. Try this, put a fresh and unmarked case in the cleaned rifled and fire it. mark the case so you don't mix it up with any others. When you get home have a look at it through a magnifying glass or even a microscope if you can get access to one. Look for a burr or drag marks around the rings left on the case, these drag marks may be hard to see, but "they will be there".
If the drag marks are from the bullet side of the rings and drag into fresh brass toward the bullet end, your problem is probably caused by rings in the chamber "standing proud" of the rest of the machining, the most likely cause being a poorly finished chambering reamer or a poor reaming operation. Solution, get the correct reamer and run it down yourself with a hand tap wrench and plenty of lube. Remember, the chamber is already reamed so this will not be a difficult operation as you are only trying to remove the very small ridges that are causing the problem, the worst of which appears to be the one right at the front, by the bullet swage. You can measure your chamber or a case and wrap some tape around the reamer so that you don't go in too far. You'll only have to turn it two or three times and remember to always turn in the cutting direction both going in and coming out.
If the drag marks on the test case are from the primer side of each ring and dragging back over the rings themselves towards the bullet end, then your problem is most likely rings cut into the chamber "lower" than the rest of the surface, in which case you may be stuck with it. You could try to carefully lap the whole chamber to smooth it out but you probably won't get rid of the problem totally and it will probably get worse again. The only solution to this would be to get the barrel re-chambered for a different cartridge. It may well be worth checking out different manufacturers cases to see if someone produces one which is slightly larger than others and chamber it for those. Remember we're talking about thousandths of an inch here, so you might get lucky!
I wouldn't go messing with dies to reduce case diameter, or you might end up with only one eye and it wouldn't be your good one.
P.S. Don't forget if using a microscope that the image is sometimes reversed depending of the number of lenses it uses, or you could end up wasting a lot of time barking up the wrong tree!
Ron
If you ignore the fact that it's a rifle and try to analyse it from a purely engineering viewpoint, as Jerry Sharret says, the marks cannot be made by a reloading die as that would always leave striations along the length of the case. Try this, put a fresh and unmarked case in the cleaned rifled and fire it. mark the case so you don't mix it up with any others. When you get home have a look at it through a magnifying glass or even a microscope if you can get access to one. Look for a burr or drag marks around the rings left on the case, these drag marks may be hard to see, but "they will be there".
If the drag marks are from the bullet side of the rings and drag into fresh brass toward the bullet end, your problem is probably caused by rings in the chamber "standing proud" of the rest of the machining, the most likely cause being a poorly finished chambering reamer or a poor reaming operation. Solution, get the correct reamer and run it down yourself with a hand tap wrench and plenty of lube. Remember, the chamber is already reamed so this will not be a difficult operation as you are only trying to remove the very small ridges that are causing the problem, the worst of which appears to be the one right at the front, by the bullet swage. You can measure your chamber or a case and wrap some tape around the reamer so that you don't go in too far. You'll only have to turn it two or three times and remember to always turn in the cutting direction both going in and coming out.
If the drag marks on the test case are from the primer side of each ring and dragging back over the rings themselves towards the bullet end, then your problem is most likely rings cut into the chamber "lower" than the rest of the surface, in which case you may be stuck with it. You could try to carefully lap the whole chamber to smooth it out but you probably won't get rid of the problem totally and it will probably get worse again. The only solution to this would be to get the barrel re-chambered for a different cartridge. It may well be worth checking out different manufacturers cases to see if someone produces one which is slightly larger than others and chamber it for those. Remember we're talking about thousandths of an inch here, so you might get lucky!
I wouldn't go messing with dies to reduce case diameter, or you might end up with only one eye and it wouldn't be your good one.
P.S. Don't forget if using a microscope that the image is sometimes reversed depending of the number of lenses it uses, or you could end up wasting a lot of time barking up the wrong tree!
Ron
Butch Lambert
Active member
I believe Marc is correct. I've had it happen before. After firing the brass it extrudes into the rings left in the chamber from trash that got between the reamer flute and the chamber wall. I was able to meaqsure it with a micrometer. They were only .0005 deep, but it made for hard extraction. You can trig it out, but you will have to cut more than you thank off the back of the tenon and to rechamber.
Butch
Butch
P
plumbago
Guest
Please, stop disecting this to death.....just do what Nash said and POLISH HONE the chanmber. I'd start with 400, but go to 600 grit for the final......It won't take long, and from looking at the cases, should FIX the problemmmm . best regards Plum
Butch Lambert
Active member
plum,
Have you thought about what you posted? If the swarf got on top of a reamer flute and cut into the chamber walls, you actually think it is smart to try to sand it out? If you sand, polish, or hone that much, you will have a shi*@y chamber.
Butch
Have you thought about what you posted? If the swarf got on top of a reamer flute and cut into the chamber walls, you actually think it is smart to try to sand it out? If you sand, polish, or hone that much, you will have a shi*@y chamber.
Butch
I just had this very problem with a AR-15 barrel. I chucked it up in the lathe and polished the chamber with 320 grit paper. I didn't try to take the rings all the way out just enough to lesson the grove and smooth the chamber. You can still see the marks on the case but it is very faint and doesn't cause any trouble. Sure beat the other ways of doing it for my project.
Glenn
Glenn
I polished the chambers on these barrels and all is better. the barrels shoot really good and i am tickled to death with them. I over think and over Analise things sometimes. This wasnt really one of those times, as i still have a stiff bolt but i dont think it has anything to do with the chamber. I dont know what it is, but the rifle is shooting fine. actually pretty darn good. I shot a .210 200 yard group today with this barrel and a few other small .3's @ 200 so i am just going to shoot the heck out of them, and use them to sharpen my wind reading skills. I will have the action looked at if and when i have a new barrel fitted to it. I will send it off to Dwight or another top benchrest smith this winter. I am sure they could figure it out pretty quick. I bought this action second hand and that makes me wonder why the original owner sold it, well i think i know why, well kinda why. Bottom line is, it's shooting good! So good in fact i think i will shoot this barrel at the east west if i can get the money to go. Raising a young family is tough at times, and i made a big move early this spring to switch all three of my comp rifles over to BAT's so i may not get to attend this year. Plus insurance is trying to screw me out of a hail damage claim, anyway what i am trying to say is that these barrels are a real bargain for a fella like me, and when they shoot this good, i cant hardly B**** about a rough chamber. Actually i feel a little selfish for even bringing it up. The problem is in the action, that i am sure. polishing the chamber helped but the bolt still lifts harder than my other BAT SV ppc rifle. Mr Schmidt's post about his action started making me think about all this, and i think there is a chance i am having similar problems, but i will let a professional make that call. I appreciate all the help here guys. More than you know!! life is pretty good, at least i own a custom rifle! I remeber a time not to long ago, that i wouldnt have been able to own anything like this. Take care and thanks! Lee Gardner