Ok so I finally got my 300 RUM back with the new Douglas barrel. When I tried to size and load the brass I had used for the old chamber I experienced sticking problems. I had my smith give me a couple more thousandths of headspace since his reamer is of match dimensions. I like the tight chamber.
Please confirm what I am thinking about the old brass. The old stuff when sized as much as my die will allow will chamber fine but sticks in the chamber with a fairly light load. (Used for breaking in) New brass shows no signs of sticking at all. Is my old brass too soft and expanding too much. Chamber checks out fine and there are no unusual marks on the brass upon firing. I guess I just thought the old stuff (Once fired) would work since it chambers easily. Any ideas as to the exact cause.
I've already bought the new brass. Was hoping not to have to since it is so expensive now.
__________________
Real leaders don't produce followers only more leaders.
One thing, I see a few people trying to setup thier throats to be real short on 300RUM's. Like they are hitting the rifling at 3.6" COL. And now they cannot get even 3200fps with 180gr bullet, and 92gr of H1000 with 180gr bullet is hitting pressure signs. As I was told from a person from clymer Reamers, the 300RUM is supposed to have some freebore. Surely not as much as a weatherby, but have some.
Also, you old brass could have expanded some and lost some of its "springiness", for lack of a better term. So now when you shoot, you might get a pressure spike.
I too a few years ago, had a 300RUM rebarreled and wanted a very tight match chamber, and my gunsmith warned against it.
To determine if you can use the brass is simple. Smoke the cartridge and see where it is sticking. Then try to size your brass where it is hitting. It is probably dragging along the body. If this is the case then just fireform the brass, and move on. Fireforming should solve your problem.
Your comment about making the headspace longer does not make any sense to me. I have never heard of lengthening the head space. That would be very dangerous, and would lead to misfires, and hangfires. I am thinking you mean that he may have expanded the chamber slightly. BC gave you the proper advice about that.
Your problem is probably not the headspace, because if it was then the bolt would be hard to close, and you did not mention that. As long as you can chamber the cartridge and close the bolt properly I would just fire form the brass with a moderate load, and move on. Trim your brass, and I am pretty sure your problem would be solved. Tom.
__________________
West by God Virginia.
We need to stop using these terms today, "Sniper Rifle", "Tactical", "Assault Weapon".
Another thing is, you might want to check with your smith on chamber tolerances are. You might have to neck turn. As you know, your necks get thicker as you shoot them. I know I necked turned 300RUM and my remington brass varied in thickness .012-.018". I usually knock everything down to .014" and not lower. But if your neck in your chamber is tighter, you might be able to nock it down lower to .012". Too low and you will have to use a bushing die or collet die.
Bingo!
Your chamber is tight, probably tight enough that un- uniformed necks are causing high pressures.
__________________
Obamanfreude - 1. taking pleasure from the misfortunes of an Obama supporter as he or she is adversely affected by the policies of their Dear Leader.
Bingo!
Your chamber is tight, probably tight enough that un- uniformed necks are causing high pressures.
Briman, I was thinking it would be easy to tell. Just take a loaded round in your new brass that chambers easy and take a loaded round in the old brass and use your calibers or mics to measure outside diameter, take the difference. You can also measure the outside diamber of your bullet, and get a rough estimation of the wall thickness.
I agree with checking the neck thickness on your old brass. If the necks are thick enough to be giving your old brass a too tight of fit you should be seeing some signs somewhere of some high pressures.
Measured neck thickness on the once fire brass and the new brass, both loaded and they are identical. Neck thickness theory disproven since the new brass is doing fine. Also I had a little more headspace added because these once fired cases that were full length sized in my dies were a little tight. Since this was a match chamber I had a little room to go with no problems. Industry commercial standard is about .oo6 and my chamber now is about .oo4 clearance.
I have since reloaded a piece of brass fired in this barrel from the first lot (previously fired). This load showed no sticking as it previously did so I am assuming the fireforming in this chamber fixed it. I just hate the thoughts of running 200 rounds through this barrel to fireform it. I'll probably stick to the new stuff. Thanks
__________________
Real leaders don't produce followers only more leaders.
Of course I know it gets thicker with repeated firings. One poster simply suggested thick necks as a possible source for my sticking brass. THe brass in question is once fired. I measured a loaded case of the once fired brass and compared the neck thickness to a loaded case in new brass. THe neck dimensions were identical. The new brass is coming out fine so it must be some other dimension of the once fired brass that is not fitting just right even though it closes fine on loaded round. THe freebore is also sufficient in the chamber and should not be the source of any of this. Again a loaded round of the aforementioned brass (fired in the factory barrel) does not stick once it has been fired in my new chamber. THanks again for the suggestions
__________________
Real leaders don't produce followers only more leaders.
Sticking brass in new barrel
