Case Forming?

[Sheltowee]

I'm currently gathering components for my first true wildcat to be built-- a 25-7 PRC built on a (you guessed it) Tikka action. I'm picking up a 25 WSSM die to handle the initial neckdown but I'll need 3 fired cases for custom dies to be built to match the chamber. In the past, I've fireformed .257 Roberts into AI by loading a standard powder charge under a cheap softpoint, easy peasy. However, there is no parent cartridge with published data to work from with the 25-7. Seems like I have two options:
(1) The Cream of Wheat method-- load the necked down 7 PRC brass with 10ish grains of Blue Dot, top with COW and a TP wad, then fire; or
(2) Take a SWAG at a powder charge, load with a cheap softpoint and fire.

Any experience one way or the other as far as best results? I don't love the idea of blowing COW through a brand new barrel but that seems like the popular choice. If you have experience with pistol powder fireforming, does 10 grains of Blue Dot seem about right? The PRC case is pretty good size.

 

[shb]

Won't the reamer print work for making dies?

 

[MThuntr]

.25-7 PRC Cartridge development and test results – West Texas Ordnance, Inc. | Custom Rifles & Accessories

westtexordnance.com

 

[Sheltowee]

Won't the reamer print work for making dies?

Should, yes, and I'm going to send that to the die maker but they also would like 3 fired cases [shrugs].

.25-7 PRC Cartridge development and test results – West Texas Ordnance, Inc. | Custom Rifles & Accessories

westtexordnance.com

Lol yep, that is who is to blame for my diving headfirst down this particular rabbit hole. They don't have any data for a 115gr. softpoint that I'd use for caseforming, though. Might end up calling them to see fi they have guesstimate. Hoping to get around 3350 with the 125gr. Hammer HHT.

 

[jeff_gibbons]

I think I’d try to extrapolate a load using light bullet 7mm prc load and a 25 pill close in weight. Then try the low charge with a faster powder.

 

[kodiakisland]

The COW method has worked for a long, long time. It's a whole lot easier on the barrel than shooting bullets down it.
I do like to form a false shoulder to ensure proper headspace so I'm not stretching brass. That shouldn't matter though to just get brass for a measurement.

 

[std7mag]

I think I’d try to extrapolate a load using light bullet 7mm prc load and a 25 pill close in weight. Then try the low charge with a faster powder.

The problem therein is that the 7PRC was designed around 180gr bullets.

Heaviest 25 caliber bullet that I've heard of is 161gr.

@Sheltowee,

You might want to try to get hold of Alex Wheeler. I think he may have done some experimental work with it.

If I were necking down the 7PRC, I would get a 7PRC bushing die and change bushing sizes.
The 25WSSM die may not center exactly.

 

[p_ham]

The problem therein is that the 7PRC was designed around 180gr bullets.

Heaviest 25 caliber bullet that I've heard of is 161gr.

@Sheltowee,

You might want to try to get hold of Alex Wheeler. I think he may have done some experimental work with it.

If I were necking down the 7PRC, I would get a 7PRC bushing die and change bushing sizes.
The 25WSSM die may not center exactly.

I think there was a thread on accurateshooter about the 25-7prc.

 

[brockel]

Gotta be close to 257 weatherby case capacity. I’d look at 257 weatherby starting loads. Would also get a 7mm prc bush die and a couple sizes of bushings to neck down with and a 25 cal expander

 

[Polaris_Doc]

I'm not intimately familiar with this method. I tried one time to fire form some brass with red dot under cornmeal and a bit of blue paper shop towel stuffed in the neck. Worked ok. What is the COW you guys are talking about?

 

[antelopedundee]

I'm not intimately familiar with this method. I tried one time to fire form some brass with red dot under cornmeal and a bit of blue paper shop towel stuffed in the neck. Worked ok. What is the COW you guys are talking about?

COW is Cream of Wheat!

 

[Wind Gypsy]

I don’t get it. You’re not changing the case body dimension right? Why not just shoot a bullet.

I don’t understand 25 wssm die unless it’s dang near free. Could just use 7PRC bushing die with smaller bushings. Sell that 7 PRC die when done if you get a new custom one.

 

[Sheltowee]

I don’t get it. You’re not changing the case body dimension right? Why not just shoot a bullet.

I don’t understand 25 wssm die unless it’s dang near free. Could just use 7PRC bushing die with smaller bushings. Sell that 7 PRC die when done if you get a new custom one.

I have a chicken or egg problem, I think, but I’m new to the wildcat game. I don’t want to order dies without having specs and fired cases, but I can’t seat a bullet without a die.

The guys at West Texas recommended the 25 WSSM for initial neck down:

The 25WSSM shares the same shoulder angle as the PRC, but has a larger body diameter and therefore has no effect on the case other than the neck. This makes the neck-down of new brass a simple and painless process, and unlike using a 7mm PRC bushing die for forming it doesn’t leave an unsized portion at the neck shoulder junction.​

 

[Wind Gypsy]

I have a chicken or egg problem, I think, but I’m new to the wildcat game. I don’t want to order dies without having specs and fired cases, but I can’t seat a bullet without a die.

The guys at West Texas recommended the 25 WSSM for initial neck down:

The 25WSSM shares the same shoulder angle as the PRC, but has a larger body diameter and therefore has no effect on the case other than the neck. This makes the neck-down of new brass a simple and painless process, and unlike using a 7mm PRC bushing die for forming it doesn’t leave an unsized portion at the neck shoulder junction.​

I see, sizing all the way to the shoulder is the reason. Makes sense. I loaded 6.5 saum with 7 saum dies/brass before 6.5 saum dies and brass were a thing and it was fine but I do think a fl die that sizes the entire neck is preferable.

Seating die should be easier to take care of with a 7 PRC die with a 257 seating stem or just universal seating die.

 

[std7mag]

I think there was a thread on accurateshooter about the 25-7prc.

Hence why my recommendation to get hold of Alex Wheeler.
Though he does have his own website.

I have a chicken or egg problem, I think, but I’m new to the wildcat game. I don’t want to order dies without having specs and fired cases, but I can’t seat a bullet without a die.

The guys at West Texas recommended the 25 WSSM for initial neck down:

The 25WSSM shares the same shoulder angle as the PRC, but has a larger body diameter and therefore has no effect on the case other than the neck. This makes the neck-down of new brass a simple and painless process, and unlike using a 7mm PRC bushing die for forming it doesn’t leave an unsized portion at the neck shoulder junction.​

With the case size being larger on the 25WSSM, THAT would be my concern!!!

If there's nothing to guide the case body, how can you ensure that the neck will be concentric with the body?

 

[kodiakisland]

I have a chicken or egg problem, I think, but I’m new to the wildcat game. I don’t want to order dies without having specs and fired cases, but I can’t seat a bullet without a die.

The guys at West Texas recommended the 25 WSSM for initial neck down:

The 25WSSM shares the same shoulder angle as the PRC, but has a larger body diameter and therefore has no effect on the case other than the neck. This makes the neck-down of new brass a simple and painless process, and unlike using a 7mm PRC bushing die for forming it doesn’t leave an unsized portion at the neck shoulder junction.​

When necking down, only neck down enough to chamber the case. There should be a slight false shoulder at the base of the neck to give positive headspace.

 

[kodiakisland]

Hence why my recommendation to get hold of Alex Wheeler.
Though he does have his own website.


With the case size being larger on the 25WSSM, THAT would be my concern!!!

If there's nothing to guide the case body, how can you ensure that the neck will be concentric with the body?

Your case doesn’t touch the side or shoulder of the die until the neck has been mostly resized already.

 

[antelopedundee]

Will it be necessary to turn your necks at some point?

 

[Sheltowee]

Will it be necessary to turn your necks at some point?

Potentially, but only coming down 27 thou I’m hoping not.

 

[antelopedundee]

Potentially, but only coming down 27 thou I’m hoping not.

Just curious, but why are you starting with 7 PRC when 6.5 is available?