300 RUM Match issue

[Sean Wilkerson]

Hi everybody. Please help me decide the best approach to an issue I'm having with a chamber. I recently had a rock creek chambered with a 300 RUM Match reamer from ptg. I was hesitant to use a match chamber in a hunting rifle that I travel abroad with but my smith headspaced it so that I can shoot factory ammo in pinch. With a slightly tighter chamber and significantly shorter FB, it definitely behaves differently than my other rum chambers.

Throughout the pressure spectrum, I'm suffering bolt click with cases that have been fired more than about twice. Older the case, heavier the click. Newer cases function perfectly. Sized cases feed fine but click upon extraction after firing. This leads me to believe the web area is growing and not getting sized enough by my FL die. Normally, I'd try a small base die but I don't believe there is one commercially available (I'd love to be corrected!). Before I have one made, I thought I'd explore my options. The way I see it, I could;

A. Have my the web area of my chamber opened up a thou or two.
B. Have a FL sizing die made to my specs. Never done this before but know a lot of shooters do.
C. Make an insert for my existing die (new to me but my smith suggested it and he's pretty crafty).
D. Accept the fact that I will only get a couple firings out of a case. Being that new rum brass is pretty much nonexistent right now, this is the least attractive.

Any opinions or experience with a similar situation?
Anybody had experience with that reamer?

Thanks to all - Sean

 

[J E Custom]

Hi everybody. Please help me decide the best approach to an issue I'm having with a chamber. I recently had a rock creek chambered with a 300 RUM Match reamer from ptg. I was hesitant to use a match chamber in a hunting rifle that I travel abroad with but my smith headspaced it so that I can shoot factory ammo in pinch. With a slightly tighter chamber and significantly shorter FB, it definitely behaves differently than my other rum chambers.

Throughout the pressure spectrum, I'm suffering bolt click with cases that have been fired more than about twice. Older the case, heavier the click. Newer cases function perfectly. Sized cases feed fine but click upon extraction after firing. This leads me to believe the web area is growing and not getting sized enough by my FL die. Normally, I'd try a small base die but I don't believe there is one commercially available (I'd love to be corrected!). Before I have one made, I thought I'd explore my options. The way I see it, I could;

A. Have my the web area of my chamber opened up a thou or two.
B. Have a FL sizing die made to my specs. Never done this before but know a lot of shooters do.
C. Make an insert for my existing die (new to me but my smith suggested it and he's pretty crafty).
D. Accept the fact that I will only get a couple firings out of a case. Being that new rum brass is pretty much nonexistent right now, this is the least attractive.

Any opinions or experience with a similar situation?
Anybody had experience with that reamer?

Thanks to all - Sean

In My Opinion, The simple and most cost effective way to cure your problems is to use a high quality SAMME reamer and have your smith clean up the chamber and re head space it.

Special dies will cure the fitting issues but wont fix the pressure problems.

I have stopped using PT&G reamers and recommend Manson or JGS because of there quality.

Free bore is a must on big over bored cartridges if you want velocity and to avoid pressure problems
and the SAMME chambers address this. with no loss in accuracy if head spaced properly and loaded correctly.

J E CUSTOM

 

[Sean Wilkerson]

Thanks for the good advice. Im glad to hear from you because i know you have considerable experience with customs rums. I tend to agree and that option has always been in the back of my mind. I've never considered the standard chamber handicapped in any way and have had great success with their accuracy. Bolt click can indeed be an indicator of higher pressures but I haven't noticed any other excessive pressure signs accompanying the click and it is nonexistent with newer cases. What is obvious though is the charge limit of the match vs saami chamber. Whereas it is common to be able run a standard rum well over book max with certain powders, this one maxes out around 91.5 of retumbo with a 200 smk. The freebore is .112 I think, roughly .100 shorter than a factory chamber, so I'd bet that's a contributor to this. I'm having to jump accubonds .050 to get quality accuracy anyway, so in this case, short FB doesn't seem to be worth the trouble. It shoots smks great at .020 but it also shot them great with a hellacious jump, before the rebuild. Thanks for your time.