several yrs ago i had a "gunsmith" build my first "custom" rifle... boy did i pay for this 1... i had a shilen #3 26" barrel chambered to .300 win mag... it sat in the safe for nearly 10 yrs before i shot it.. needless to say the warranty ran out before it went bang... anyway, it marks the brass really bad, with a bright ring about 1/4" past the belt..the action is hard to open after the gun is fired.. i've only shot factory winchester ammo in it... it's headed to tip burns tomorrow for repair... question is, what will clean up a .300 win mag chamber???... i don't want to open up the bolt face, ive got a new .300 rum... will a .300 H&H clean up the chamber????...what about a .300 wby???.....i dont care if i loose some barrel lenght by cutting off and rechambering..if all else fails, i'll go back to the .300 winmag...thanks.... ,

This doesn't sound like a rough chamber scratching the brass. This senario makes me think something is causing excessive chamber pressure. Maybe the chamber needs to be measured to see if the chamber is too short and is pinching the necks on factory ammo. If this is the case all that would be needed would be to recut the present chamber a little to add lead. If this were my rifle I would exhaust all other options before making more expensive alterations to it.

Check head space & do a chamber cast.

Length is good but the taper on a 300 H&H is probably too great. A 300 Weatherby will clean it up. Having a 300 RUM still does not give you much difference.

300 webby MIGHT clean it up, as it sounds like an egg shaped chamber...if the problem is close to the belt, no, it wont.

factory ammo, and it's hard to extract? not a short headspace issue..

300 RUM will clean it up, its the largest ofthe "normal" 30s .. roughtly .018 larger and will clean up the neck/throat too

300 hh, no way, it's smaller

setback and rechamber would be my first step... then rebarrel to a 470 or 500AR
jeffe

Do you know how to clean a rifle properly? Use a brush to clean your chamber and clean your lug recesses as well.I had a friend with the same problem and called me nuts when I told him to clean his chamber.He later told me the problem went away after a simple cleaning of the chamber.

quote:

Originally posted by shootaway:
Do you know how to clean a rifle properly? Use a brush to clean your chamber and clean your lug recesses as well.I had a friend with the same problem and called me nuts when I told him to clean his chamber.He later told me the problem went away after a simple cleaning of the chamber.

he aint worried about breaking the stock... shoo thataway

Sounds to me like a ring in the chamber. It would take a setback of the barrel by the amount from the front of the belt to the ring he described; maybe less than a half inch.

Jim

Can you post a photo of a fired round? This would help analyze your problem.

If it is a bad chambering job, then you can solve it (1) by setting back a quarter-inch or so and rechambering, which with your 26" barrel isn't giving up much, (2) rechamber to .300 RUM, or a wildcat based on the .375 Ruger, neither of which require a bolt face alteration.

Simply rechambering to another .530" belted magnum case will not address the presumed defect in the rearward part of your chamber.

The bright ring in front of the belt isn't that uncommon. And unless some sort of cleaning regimen was followed for the 10 years it sat in the safe, he could very well have a dirty/rusty chamber. For a first step, I'd suggest having a smith polish the chamber. Then a chamber cast would tell him which way he needs to go.
I would think the original smith fired a couple of test rounds thru it when he was finished with it. So too much can't be wrong.