The PRC die "problem"

nkyshooter said:
I think my decision between PRC and SM may have just been made ...

Worst case scenario is firing actual 300 PRC ammo in the SM ... the SM will allow me to 'download' to lower pressure and get same velocity as the PRC ... but with better brass life and have the tank available for higher if ever needed.

Let me know if I am wrong @elkaholic ...
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You're spot on
 
Alex Wheeler said:
There are a number of people experiencing sizing issues with the PRC case. When designing a chamber, brass, and resize die there is no one size fits all. We want good hard case brass, but its harder to size. We dont want sloppy chambers either. I have experience with designing reamers with hard brass and in my opinion the PRC base diameter is just too small to work. The die specs are not the main problem. You cant make a die much smaller than the solid web without it cracking. And once a case head expands a little no die can fix the clickers that you will get.

Looking at the 300 PRC and ADG brass there is only .003-.0035" difference between a virgin case head and the chamber. Thats not enough for this type of brass in a magnum case head. And will lead to long term problems.

I already have reamers spec'd out for myself with other changes, but I have spec'd new ones and will post the prints here with the only change being to the base size. That in my opinion should have been the Saami spec to begin with. They should solve most all of your sizing issues. The dies still needs to measure .5295"-.530" at the base though. Many are polished out.
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Appreciate the information
 
Jud96 said:
So if I'm understanding this correctly, the chamber is too tight for the brass? Sorry I just now am learning about this issue.
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Yes, and the dies currently available cannot get the base of the case small enough. This happens with the mag cases based on the 375 H&H a lot. Reloading Tech has a die that fixes the orebelt bulge. This is a similar issue. Maybe they'll take of this challenge. My cases that don't fit are running up to .5335 and .534. a virgin Hornady case is usually around .527. The chamber spec is .533, so .0005 is too much.
 
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I've personally experienced this in my 300 PRC and ADG brass. I started with a whidden full length bushing die... first load just expanded the necks and loaded, then full length sized after the first firing. No problems on first or second firing. Third loading same deal FL size expand for neck tension, loaded rounds chamber fine, shoot fine but stick in the chamber, like completely stuck, can't be removed with the bold. I had to knock them out with a cleaning rod. Measure brass and they are a couple thousand bigger at the web than sammi says they should be (can't remember the exact numbers) I can look them up if need be. Phone whidden they blame ADG brass for being too tough. Say they will make me a custom die if I send 3 pieces of brass in.... that was March, still no die. In the interim I ordered a Redding standard FL die and ran the rest of that twice fired brass through that die and they chamber, fire and eject no problem. I haven't reloaded that batch of brass again but it will be interesting to see if the Redding die will keep them in spec. I've heard, and this is just speculation so take with a grain of salt, that other people have had similar issues with whidden dies in other calibers not sizing the web area down enough. A couple of these guys felt the problem was the use of aluminum in the die which gave or flexed allowing the brass to remain too large. I don't know about that but I can tell you my Redding die fixed my issue for now. I've really only heard of this issue with whidden dies and ADG brass. There's a bunch of 300 PRCs out there and lots of people shooting ADG brass in them but I've only heard of this coming from a few guys, really makes me wonder what the issue truly is, dies, brass or chamber.
 
This NOT a brass issue. ADG makes very good brass and the last thing we want to do is have them "dumb down" their brass to fix a chamber and die issue. We want hard brass. This boils down to having a chamber that is big enough over the virgin brass so you can design a die that will work. If you look at the ADG saum brass you have a difference of .0055" between new brass and the chamber at the base. With the PRC its .003". So you can easily make a saum die that will work, not as easy with the PRC.
 
Alex Wheeler said:
This NOT a brass issue. ADG makes very good brass and the last thing we want to do is have them "dumb down" their brass to fix a chamber and die issue. We want hard brass. This boils down to having a chamber that is big enough over the virgin brass so you can design a die that will work. If you look at the ADG saum brass you have a difference of .0055" between new brass and the chamber at the base. With the PRC its .003". So you can easily make a saum die that will work, not as easy with the PRC.
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If a guys already got a 6.5 or 300 prc and is having, or it's known his going to have this problem, would you recommend chucking their barrels up in a lathe and polishing out a few extra thou for the first 1/3" of the chamber to remedy this? I have a 6.5 prc that get clickers on warm loads, and my 7/300prc is almost complete. I'd live to avoid that issue in the new rife.
 
Alex Wheeler said:
Based on what I have done on other chambers with the ADG brass, I think the .2" line on this case should be .535". I am having reamer prints drawn up with that being the only change and will post them here for those who want them. They will be Saami in all other dimensions.
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That is actually the high end of SAAMI unless I misunderstand the print.
 

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