300 PRC SHERMAN IMPROVED

[elkaholic]

Here is a batch of PRC brass loaded with 225's and a big gulp of RL33 ready to form in my improved chamber in early January. The 2 cases on the right are the old 30/375 S.I. which will look identical, to the naked eye, when formed in the new chamber

 

[elkaholic]

If anyone has access to some loaded factory prc ammo, could you please get me a measurement of the neck o.d. half way down the neck. (Loaded round)
Thx!

 

[FURMAN]

If anyone has access to some loaded factory prc ammo, could you please get me a measurement of the neck o.d. half way down the neck. (Loaded round)
Thx!

I should have some in the next week. I am very interested in seeing how accurate those fire forming loads are.

 

[elkaholic]

I should have some in the next week. I am very interested in seeing how accurate those fire forming loads are.

I have a feeling they are going to shoot almost the same, accuracy wise, as in a prc chamber. They will likely be about 50' less velocity?

 

[elkaholic]

It looks to me like Hornady put nearly .007" clearance in the neck (chamber) with factory brass! This is less than ideal but that's the safety built into things I guess. My chamber will be tighter and will allow enough clearance while allowing for neck turning if you want. This will give better accuracy in the custom chamber.

 

[yorke-1]

So what's the difference between your original 30/375 SI and your PRC version? I'm guessing that the shoulder on the PRC is a little farther forward than on your original 30/375 SI. You moved it back quite a bit compared to the 375 case right?

So far I really like what you've got going here!

 

[elkaholic]

So what's the difference between your original 30/375 SI and your PRC version? I'm guessing that the shoulder on the PRC is a little farther forward than on your original 30/375 SI. You moved it back quite a bit compared to the 375 case right?

So far I really like what you've got going here!

It's very close to my old version! I took a little more taper out and moved the shoulder forward very slightly. The throat is a little longer than my old throat so overall, there should be a slight gain in performance. The old version performed VERY well so the biggest plus, IMO, is being able to shoot factory ammo and fire forming at the same time. I noticed tonight when priming the prc brass with my strip loader, it took a lot of pressure which tells me they tightened up the pockets which should help brass life a little. It felt similar to priming RWS brass! We'll see?

 

[yorke-1]

I've been looking for a 30 caliber to chamber up as another barrel for my Nucleus action and this would be a perfect. I'll be in for one as soon as you've got it ready to go and your dies are in.

 

[elkaholic]

I've been looking for a 30 caliber to chamber up as another barrel for my Nucleus action and this would be a perfect. I'll be in for one as soon as you've got it ready to go and your dies are in.

Do you want to buy a reamer, or rent? I may have to order more reamers. Quite a few people are all over this one!

 

[yorke-1]

Do you want to buy a reamer, or rent? I may have to order more reamers. Quite a few people are all over this one!

I'll probably just rent one. It's unlikely I'd go through more than one barrel.

 

[elkaholic]

I'll probably just rent one. It's unlikely I'd go through more than one barrel.

Ya, I you can always rent it again. I have around 1600 rounds through mine and it still shoots great!

 

[elkaholic]

These were targets from my early developement

 

[elkaholic]

The first official fire forming from actual 300 prc brass went off without a hitch today. I was able to chamber it in my old 30/375 S.I. chamber and used a known velocity load that was not too hot. It formed up beautifully with no signs of pressure. The load (225 eldm) previously chonographed at 2970' in my S.I. chamber with 375 Ruger brass. The new chamber will create a little LESS pressure, so all looks well!

 

[yorke-1]

Looks good!

Do you have have a smith who's going to get a reamer and doing any chambering? I got to thinking that it'd probably easier for me just send a barrel and action to a guy who already has a reamer instead of renting a reamer from you and having it sent to a smith.