The PRC die "problem"

Truc

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Mar 18, 2012
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Wolfesville, MD
I’m waiting for Lapau to make their brass available, then I‘ll get a reamer and sizing dies to fit Lapau. If anyone thinks brass doesn’t matter just look at 6BR Remington and 6BR Lapau. I have a 6.5 Rem Mag now so big rush
 

Alex Wheeler

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Jul 5, 2017
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I have caught plenty of grief for identifying different problems. I wouldn't bother if I didnt care. I really like the PRC cases which is why I want to see them succeed. No doubt plenty think I am a fool or have motives. But theres no money in giving away reamer specs and JGS does not give kick backs or discounts. So you either think I am a liar or you don't.
 

milanuk

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Jan 21, 2002
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Wenatchee, WA
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.
Yes, thats the cheap easy way to fix it.

Alex,

As someone who is literally just getting ready to get rolling with a .300 PRC project (as in the last part showed up a couple days ago)... and with dies from the manufacturer that I think y'all are hinting at, and 150 pcs of ADG brass... what's the best way for a lay person such as myself to check and see what the actual dimensions of that area of the chamber and die are? I'm assuming using the back side of a set of calipers isn't accurate/reliable enough for this?

Kinda wanting to get the project going... not excited about having to modify a brandy new barrel, or replace dies... but not thrilled at the notion of having to replace the brass early, either.

Monte
 
Last edited:

phorwath

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Apr 4, 2005
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Alaska
Hope this doesn't add to any confusion..., but here goes. I own two finish chamber reamers. 1) for my .338 Lapua Rogue, and 2) for the equivalent of the 30 Sherman Magnum.

I have barrels chambered with both of these reamers that have been removed from the actions. So I could easily measure the ID of each chamber at the breech face with 0.001" calipers. Both chamber IDs measure right around 0.001" larger in diameter than the 0.200" datum of the respective chamber reamer spec sheets.

I've never chambered a barrel blank, but it appears that the chamber diameter, after reaming and polishing the chambers with the common 320 grit surface, end up being about 0.001" larger in diameter than the finish chamber reamer OD spec'd at the 0.200" datum. Gunsmiths that chamber barrel blanks probably know this off the top of their head.

Just a curious engineer...
 

P7M13

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Jan 5, 2016
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Orygun
Got nothing to do with Sherman Magnums or those that shoot Sherman Magnums.

The thread title is PRC. And PRC chambers cut to a spec that is too small in diameter at the case web is the crux of the problem.
Not a Wheeler or Sherman problem. Wheeler's the guy identifying the problem, and the cure.
Well my wife tells me I'm a horrible communicator, and by you misunderstanding what I wanted to say, must be so.

I wasn't stating it as their problem, at all.
This is a problem, specific to PRC as @Alex_Wheeler pointed out.
I'd speculate it also happens in other cartridges, but depends on who made the rifle.

Point being,
  • If you push your pressures, it's more likely to happen
    • This is a forum where people do that, a lot.
  • If you really want to get the most out of your LR rifle, and push the pressures, accept that
    • Without modification (esp on the 300 PRC chamber), you will likely result in cases sticking as the base web expands under the pressures
    • Standard, OTS dies won't remedy that problem.
    • Best solution is to have a capable 'smith modify your chamber, and
    • get a custom set of dies.
My attitude is, LR is like a hot rod : you may only get four reloadings out of your brass before they start clicking. Modify the chamber, get better dies, or settle for just a few reloadings and buy more brass - you decide.
As stated before, it's not the brass' fault. It can be remedied by modifying the chamber and getting dies that properly size the case, all the way to the shell holder.
 

rfurman24

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Aug 29, 2010
Messages
2,919
Location
Kansas
Well my wife tells me I'm a horrible communicator, and by you misunderstanding what I wanted to say, must be so.

I wasn't stating it as their problem, at all.
This is a problem, specific to PRC as @Alex_Wheeler pointed out.
I'd speculate it also happens in other cartridges, but depends on who made the rifle.

Point being,
  • If you push your pressures, it's more likely to happen
    • This is a forum where people do that, a lot.
  • If you really want to get the most out of your LR rifle, and push the pressures, accept that
    • Without modification (esp on the 300 PRC chamber), you will likely result in cases sticking as the base web expands under the pressures
    • Standard, OTS dies won't remedy that problem.
    • Best solution is to have a capable 'smith modify your chamber, and
    • get a custom set of dies.
My attitude is, LR is like a hot rod : you may only get four reloadings out of your brass before they start clicking. Modify the chamber, get better dies, or settle for just a few reloadings and buy more brass - you decide.
As stated before, it's not the brass' fault. It can be remedied by modifying the chamber and getting dies that properly size the case, all the way to the shell holder.


I can not speak for others but the PRCs I have I have tested this with very low pressure loads. The problem is NOT high pressure. Velocities are slow in testing. The primer pockets are still tight as new in 6-7x fired cases. No hard bolt lift. Not ejector marks. The issue is sizing period.
 

elkaholic

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Dec 4, 2008
Messages
9,596
Location
hauser, id.
Well my wife tells me I'm a horrible communicator, and by you misunderstanding what I wanted to say, must be so.

I wasn't stating it as their problem, at all.
This is a problem, specific to PRC as @Alex_Wheeler pointed out.
I'd speculate it also happens in other cartridges, but depends on who made the rifle.

Point being,
  • If you push your pressures, it's more likely to happen
    • This is a forum where people do that, a lot.
  • If you really want to get the most out of your LR rifle, and push the pressures, accept that
    • Without modification (esp on the 300 PRC chamber), you will likely result in cases sticking as the base web expands under the pressures
    • Standard, OTS dies won't remedy that problem.
    • Best solution is to have a capable 'smith modify your chamber, and
    • get a custom set of dies.
My attitude is, LR is like a hot rod : you may only get four reloadings out of your brass before they start clicking. Modify the chamber, get better dies, or settle for just a few reloadings and buy more brass - you decide.
As stated before, it's not the brass' fault. It can be remedied by modifying the chamber and getting dies that properly size the case, all the way to the shell holder.
Im running 3000' with multiple firings on the same exact brass with 245 Bergers and have never stuck a case yet or loosened a primer........WHY?
Pretty sure its not low pressure!
Lots of clients doing the same.
 

highdrum

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Joined
Nov 30, 2008
Messages
2,140
Location
Montana
Im running 3000' with multiple firings on the same exact brass with 245 Bergers and have never stuck a case yet or loosened a primer........WHY?
Pretty sure its not low pressure!
Lots of clients doing the same.
Thats a long barrel gun isn't it Rich, 28"?
 

IHFarmer07

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Joined
Dec 29, 2013
Messages
270
So if a person were to get a custom die, who would you all suggest that will actually listen.....Hornady the only one?
 

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