Where to find 300 PRC brass

Capt have you necked it down in the past? I'm in the same boat I bought 416 Ruger necked it down to 375 Ruger annealing it and next step to neck down to 300 PRC. That's the step I'm sketchy on, that's a big step! Do you use a standard 300 PRC die without the stem or is there a die between? Would love some help before I trash the 375 brass? Also ordered a .308 internal neck reamer. I've only necked down 8mm mag to 7 STW which is easy run it through the die and send it!!!

Use a 338 RCM die to go from 375 down to 338, then use the 300 PRC die.
 
I have a née box of 50 ADG brass I'll sell you. It's necked down to 7mm but I can bring it back up to .308. I feel for ya. Having a new custom you can't shoot would be about the worst thing ever!
 
I have not done anything with the prc in awhile. I have neck bushings for 35(.385) and 8mm(.350) I will use in my prc die. I will anneal after the 8mm pass and after the 300prc pass then turn. I have a bunch of 110grn flat base bullets I will fireform with then ream and turn. I'm hoping that I can find 100pcs then I might sell the 375 stuff as I don't have the time to do all that at this point in time.
 
My approach is neck down the .416 to 375 Ruger (did that) anneal, neck down using a raised 338 RCM die (waiting delivery), anneal again and then run them through my 300 PRC die, load and send it! They are all based on the 416 Ruger so no taper and all same dimensions except length Any thoughts?
 
My approach is neck down the .416 to 375 Ruger (did that) anneal, neck down using a raised 300 RCM die (waiting delivery), anneal again and then run them through my 300 PRC die, load and send it! They are all based on the 416 Ruger so no taper and all same dimensions except length Any thoughts?
338 RCM not 300 RCM
 
My approach is neck down the .416 to 375 Ruger (did that) anneal, neck down using a raised 338 RCM die (waiting delivery), anneal again and then run them through my 300 PRC die, load and send it! They are all based on the 416 Ruger so no taper and all same dimensions except length Any thoughts?
That's pretty close, but it will be a bit more work than that. The shoulder on the 300 PRC is pushed back slightly farther than the 375 Ruger case. You can do this with the 338 RCM die once you get a feel for it, but you'll probably crush a few cases in the process. Ideally you'll want a 300 PRC case on hand to setup the 338 RCM die.

Here's another option, but one that won't work with all actions. You can form 300 PRC cases from 8x68s brass without too much effort, but the rim diameter is a little smaller than a standard .535" magnum bolt face. Some actions will work with the smaller rim, some won't.

84aAbns.jpg

left to right: 8x68s RWS brass, 375 Ruger case, 338/375 Ruger formed from an 8x68s case, 300 Sherman Mag (300 PRC Improved) formed from 375 Ruger brass, 6.5/375 Ruger from 375 brass, 7mm LRM formed from 375 Ruger brass.

You can see the difference in the rim and case head between the 8x68s case and the 375 Ruger case. The 8x68s brass will result in reduced case capacity, but not enough to cause a major drop in performance. I think it would actually be easier to form 300 PRC brass from the 8x68 case than using 416 Ruger brass.
 
That's pretty close, but it will be a bit more work than that. The shoulder on the 300 PRC is pushed back slightly farther than the 375 Ruger case. You can do this with the 338 RCM die once you get a feel for it, but you'll probably crush a few cases in the process. Ideally you'll want a 300 PRC case on hand to setup the 338 RCM die.

Here's another option, but one that won't work with all actions. You can form 300 PRC cases from 8x68s brass without too much effort, but the rim diameter is a little smaller than a standard .535" magnum bolt face. Some actions will work with the smaller rim, some won't.

84aAbns.jpg

left to right: 8x68s RWS brass, 375 Ruger case, 338/375 Ruger formed from an 8x68s case, 300 Sherman Mag (300 PRC Improved) formed from 375 Ruger brass, 6.5/375 Ruger from 375 brass, 7mm LRM formed from 375 Ruger brass.

You can see the difference in the rim and case head between the 8x68s case and the 375 Ruger case. The 8x68s brass will result in reduced case capacity, but not enough to cause a major drop in performance. I think it would actually be easier to form 300 PRC brass from the 8x68 case than using 416 Ruger brass.
I agree and purchased some 8x68s unfortunately my Defiance actions bolt face doesn't like it
 
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