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Polish rear of chamber?

I've been getting a click at the top of bolt lift on my 300 win mag. Bolt lift is usual until it gets 90% to the top then I have to push real hard and it "clicks or pops" and it opens fully. Brass is not indicating excessive pressures. I was told the chamber was reamed too tight near the base of the case and needed to be polished out .002. I just had it rebarreled and lugs lapped to just contact. It seems to be in time but I'm not real sure
 
Couple of basic questions first. Do you reload and if so, full length size your brass? 2- did you put any lube on the cam area of the bolt? It needs a touch of grease to do its job. The "snap" may be just metal to metal as the bolt cams out. Don't go polish or grind or anything on that chamber yet!
 
Don't polish anything until you have lubed your bolt and cam surface. Was the brass fired in a different rifle or is it virgin brass? Polishing. 002" is a heck of a lot in my opinion. Polishing a chamber should do nothing more than improve the surface finish, not remove any appreciable amount of metal in my opinion.
 
Since you mention pressure signs, I assume you are shooting reloads, and that the problem does not occur with new (unfired) brass. The problem that causes "bolt click" is hot loads and a sizing die that does not fit the chamber closely enough. The best answer is a custom die, but probably the easiest (quickest and cheapest) answer is a die like this one: http://www.larrywillis.com/300winmag.html
 
This happens in new and old brass both Winchester and RWS both. I have lubed the caming surfaces and backs of the lugs as I always do. It has done this since the barrel was rechambered 2 months ago. After the gun is fired and clicks, I can take the brass out, put it back in and it does the same thing. Here is a pic of the brass, you can see how it looks tight at the rear like it gets in a bind.
The line at top of brass is from the bullet case.
A23CA9D6-46FA-4CBD-BE02-57F46CCEA3CD-77424-00001546132D606C_zps6fee8d71.jpg
 
It looks like the chamber might be a little rough in the back. How much is your Fl die reducing the diameter of the back of the case... about .1 in front of the belt?
 
BoydAllen said:
It looks like the chamber might be a little rough in the back. How much is your Fl die reducing the diameter of the back of the case... about .1 in front of the belt?

It is sized all the way down. It fits fine before firing. I have a Larry Willis collet die and make sure it will drop in the top of it after every resizing.
 
If you are very sure that it is not just pressure, given that they go in fine, I would do some chamber polishing, not so much for dimension, but for finish. Let us know if you fix it.
 
I'm gonna step out on a limb and say that you probably have more than one problem. I agree that the chamber might benefit by a little polishing, but I would guess that the major problem is poor primary extraction. I asked earlier about the make and model of the rifle because it's pretty common to fight extraction in certain actions. If you have a Remington action I will suggest a quick test that may shed a little more light on what's going on here. Take a feeler gauge and see how much clearance there is between the front of the bolt handle and the bolt handle notch in the action. If it is a Remington, I will take a guess and say that you have at least .012 to .014 clearance and it's quite possible that it's more. Give that a try if you can and see where that leads us.
 
The best I could tell, I have .011 clearance. I put the same gauge on a Remmy 308 that's in the safe ( that has never had issues) and got the same measurement. I thought it was an extraction issue also, so the other day when I was shooting the gun and getting the clicks I watched the bolt handle very close while extracting. The bolt handle was contacting the cocking ramp at the base of it, I dont think it could get any closer. I also smeared a fine dab ( couple thou thick at most) of white action grease on the base of the cut out for the ramp. I fired a round and extracted a case while watching closely and the grease smeared. I'm no gunsmith, but that told me I wasn't hitting way up the ramp and losing extraction.
 
.011 is not bad and pretty typical of where Remington puts them, but it can still give you poor extractor performance. I have a couple of rifles that both did exactly what your rifle is doing and both of those bolts were slightly further back than yours at .014 and .015. They were a pain in the a$$ to shoot like that so I had Dan Armstrong move the handles up to .005 clearance and the cases pop right out no problem. I know 5 to 10 thousandths doesn't sound like much change but it can make all the difference in the world. Give your chamber a little polish and if that doesn't do it get in touch with Dan a he'll fix you up.
 
Re-timing is going to be the next step. How much does a timing job cost? Im 3 grand in this already and still don't have a gun to shoot, kinda disheartening.
 
I don't remember exactly what it cost but I want to say it was between $40 and $50. Shipping to Alaska can be a bit expensive, but you can ship the bolt only and put it in a USPS small flat rate box for about $6. It's money well spent as you only have to do it once and that action is good to go for a looooong time. I have a 60's vintage 40-x .223 AI that had poor PE and I hated to shoot that rifle because of it. I had to pull the bolt back to manually extract each case... not what you want to have to do in a good p-dog town. I sent it to Dan and that rifle is a pleasure to shoot now. It extracts like butter.
 
I would have to let someone who knows exactly what they were doing with the feller gauges check it so I would know how far forward it needed to go. 40 bucks is cheap and almost unbelievable. What is the best distance from the action face for good lift?
 
Your picture helped. I say polishing out the scratches is in order. The marks shown aren't deep, just need to be smoothed out. Becareful of what you use to only polish and not grind. The dimensions you gave for the primary extraction are in order for factory stuff. If it were mine I would polish and see what that gets you before shipping it off. In the long run you may have to have the timing set but worth a try first to polish.
 

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