Converting 375 Ruger Brass to 300PRC

[b2lee]

I figured I'd pull this nugget out of the 300PRC thread in the ELR - Beyond 1000 yards forum. I hope this finds a new audience. It has been very beneficial to some. However, it is getting buried in that thread and hard for new people to find....


So, we all know that ammo for the 300PRC is scare in the market place. We also know that finding reloading components have been frustratingly scarce as well. Powders hit websites and are sold out in mere seconds. Same with primers, bullets and brass. With ADG not planning to come to market with more 300PRC brass until months from now, and the Lapua release that may get back up into summer, what exactly are we to do? Buy Hornady brass? Have you tried finding that lately? It has been gobbled up off the market as well. With competition season approaching, many people are getting nervous about not having anything. I myself have lowered my powder loads on my 230gr A-Tips and my new 245gr EOL's just to baby my brass so it will last longer.

Well, let me give you an alternative. Just incase the brass of ADG and Lapua get pushed back to a point that makes it to where you can't shoot, let's walk through one of the simplest brass resizing/substitution jobs you will ever encounter. I'll walk through how to turn 375 Ruger brass into 300 PRC. Yes, going from the parent to the child case. After this you will see how simple it is, and you will see that it wasn't much innovation to take the 375 Ruger to the 300 PRC. Wildcatters did it first and Hornady just SAAMI spec'd it and called it Easy Money. The cartridge is my current favorite for 1000 to 2000 yards...and slightly beyond. Now...let's take a look.

So, I'm using my normal full length sizing die with the expander ball removed...I never run an expander ball. I'm using a 334 bushing. I would not use a non-bushing die because it squeezes down too small. I did not find it necessary to go bigger and do two or more sizing operations making the neck smaller each time. I did however only partially size in a few steps pushing the neck in and the shoulder back. Let's take a look:

View attachment 7532157

The 375 Ruger next to the 300PRC. You will notice that the cases are really close in OAL. You will notice that the 375 neck is much higher up and the shoulder angle is different. Everything else is very close, like body taper. So, I sprayed everything with Hornady One Shot and let dry. Next I attacked only half of the neck.

View attachment 7532159

You will notice I only did a partial neck sizing. Look how the brass being squeezed in for the new neck diameter and flowing down. I only did a partial size here, lifted the handle...and then gently went for the remainder of just the neck.

View attachment 7532163

Neck is done, but we haven't attacked that shoulder yet. What I do here is to slowly push that shoulder back...If for any reason I feel a little extra resistance, I'll pull back and do the shoulder in two steps just like I did with the neck. After the first one I measured and lowered my die just a few thou and finally got it to where the 375 Ruger was sized down and coming out within 0.0005....aka half a thou of my ADG brass measured from base to shoulder using a Short Action Customs 30 degree shoulder angle Comparator Gauge. They came out pretty nice.

View attachment 7532165

375 Ruger on the left and 300 PRC on the right. The surprising part is: After all this, I measured the OAL and came to 3.871 on all of them. I trim at 3.870 and my trimmer barely made a sound as I took these to 3.870. I ran them through a neck expander mandrel that slightly moved them out to what I prefer my neck tension to be. I will load these up and probably shoot them this weekend. I'll anneal them after and run them through the reloading process just like the ADG brass and see if some of that brass flows forward and grows. I will see just how much brass I have to trim. I'm expecting a little flow forward. We will see. If I do see a donut forming I will neck ream and report my findings.

These should shoot just wonderful. The only problem they should have is the inherent primer pocket failures that are known in Hornady brass. I hope this tutorial will help at least one person who may be stuck in a situation where they want to shoot their 300PRC but either have no brass, or they are afraid of damaging/losing the precious little they have.

 

[b2lee]

For some follow up discussion...you can follow this link to the original discussion: https://www.snipershide.com/shooting/threads/300-prc-update.6890837/page-75#post-9216761

 

[b2lee]

I want to point out this fact.....this converted brass isn't to 'Just get by in hard times'....it is a very viable and can be a very successful brass to use even in the toughest competitions.

The following was NOT a winning target...but it was a 2nd place finish in a shoot off in 1000yd Bench Rest in some strong winds that were both switchy and variable speeds....so the wind reading was ALL my fault...the verticals on these shots is just insane.... Vertical was 0.715"

 

[Mike Casselton]

If you're using RCBS or Redding dies, you can use your seater die as an interim step before FL sizing.
It works best if your seater has been polished inside with Flitz.
Just remove the seating plug and if you're using One Shot lube, give it a spritz inside.

 

[drummachinejoe]

Would you

So, I'm using my normal full length sizing die with the expander ball removed...I never run an expander ball. I'm using a 334 bushing. I would not use a non-bushing die because it squeezes down too small. I did not find it necessary to go bigger and do two or more sizing operations making the neck smaller each time. I did however only partially size in a few steps pushing the neck in and the shoulder back. Let's take a look:

View attachment 7532157

The 375 Ruger next to the 300PRC. You will notice that the cases are really close in OAL. You will notice that the 375 neck is much higher up and the shoulder angle is different. Everything else is very close, like body taper. So, I sprayed everything with Hornady One Shot and let dry.

Would there be any problem using Dillon Case Lube or 99% Alcohol & Lanolin mix instead of Hornady One Shot?

I saw pictures in the 300 PRC Update thread where too much lube was used. Do you think the Dillon Lube would make for too thick of a coating?

 

[918v]

Have you tried a Lee .338 Win Mag collet neck die with a .304” mandrel?

 

[b2lee]

We haven't seen much 300PRC brass lately. I was in Sportsman's Warehouse the other day and saw a bag of Hornady 375 Ruger brass and thought of this article. There have been a lot of 300PRC rifles made since this article. If any of you newbies are having problems getting brass to feed your rifle, you may want to visit this subject of necking down 375 Ruger brass.

 

[SEPAboltrifle]

Resurrecting this discussion: given the relative popularity of .300 PRC chambered rifles, Hornady one-time fired brass is readily available.

 

[b2lee]

The 300PRC in the hunting sphere has exploded more than I thought it would. The availability of brass is still really bad. When I see brass drop it is gone in mere seconds. I'm still seeing some 375 Ruger brass on shelves at places like SPortsmans' Warehouse.