300WM Small base sizer

[Punisher29073]

I have a 300WM with a match chamber in it. I have not found any once fired brass that will fit the chamber even after sizing with a full length sizing die. Is there a chance a small base die would fix this and if so, what percent chance?

Also if there is anyone out there with this die I could send a couple pieces to size and send back to me, that would be appreciated.

Thanks

Ryan

 

[George63]

if you are using a RCBS, another brand may get you smaller, otherwise it may be more shoulder bump is needed not a small base

 

[Punisher29073]

I can see the scuffs on the brass at about 1/2" above the base. That's what made me think the small base might help.

Ryan

 

[Fuzzball]

I know of no one who makes a SB die for .300 mag. Turn your present sizer down another 1/8 8urn, that will probably be as SB as you'll need. If not, web search Innovative Technologies and get one of Larry's collet body sizers.

And next time you get a new barrel don't get a match chamber.

 

[Punisher29073]

Rcbs makes one. I will try the 1/8 th turn and see what happens.

I got a deal on the rifle and did some horse trading on components. Now Im seeing the deal may be due to this brass issue. I'm happy with it though. After tuning I have the 300yd groups down to 1.6-1.8". This match chamber business is rediculous. Does it make the brass last longer?

Ryan

 

[FLIGHT762]

Are you sure you're just not bumping the shoulders of the cases enough? How are you measuring your shoulder bump? Are you using a gauge? 4 out of 5 of my tight chambered rifles never needed a small base die.

The only rifle I owned that needed a S/B die is a Steyr SSG 69, that chamber is very tight in the web area above the case head. I had to use a Redding 308 Small Base body die to get the web resized @ .468" so I would get smooth chambering, RCBS Small Based die didn't size the web down enough. Didn't matter how far I was pushing the shoulders back, It was a tight area in the web.

Your rifle might be the same, but I'd check shoulder bump first before ordering a S/B die. I have an Innovative Technologies collet die that corrects the web area after multiple firings, but that may not be your issue. I'd turn the die in a bit more as Fuzzball suggested, if you can. A 1/8th turn of the die will move your shoulder about .009". You might only need half of that. I've found at times, turning the die in just several millimeters will get the job done.

 

[Punisher29073]

Ding ding ding!!! Fuzzball wins tha prize! That 1/8th turn did the trick. Perfect. Fuzz saved me $50. Thank you kind sir.

Ryan

 

[bigedp51]

I know of no one who makes a SB die for .300 mag. Turn your present sizer down another 1/8 8urn, that will probably be as SB as you'll need. If not, web search Innovative Technologies and get one of Larry's collet body sizers.

And next time you get a new barrel don't get a match chamber.

Punisher29073

Fuzzball hit the nail on the head, many people have your problem and the Innovative Technologies Belted Magnum
Collet Resizing Die takes care of the over sized base above the belt. I would email Larry and explain your problem with your match chamber before ordering to make sure the collet will size the case small enough for your match chamber.

As a side note my RCBS small base dies only make my 30-06 and .223/5.56 cases .0005 smaller in diameter than my standard FL die "BUT" the small base die sizes further down on these cases.

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