Savage rifle, wildcat caliber-your thoughts

[wildcat westerner]

Hello, In the 90's I built a switchbarrel rifle=6.5x284 and also a wildcat 30 caliber based on the 9.3x64 RWS. Using the standard boltface and turning down the rims on the RWS cases we were able to fit the much larger RWS brass into the rifle and four of them fit readily in the magazine! When testing at the range we hit 3,214 fps with 180 grain bullets and Retumbo, and an engineer saw the chronograph and that barrel and three cases used for making dies went home with him. Since then we recently converted a 30-06 Howa to my wildcat caliber successfully for a friend and I got the yearning to have a barrel in my old wildcat once again. I stumbled onto some brass, a barrel is coming, and a muzzlebrake has been ordered.
A person I respect has taken me to task for turning down the rims as to the strength factor of that RWS brass. I realized we did achieve magnum performance from that case long ago and also the brass I used then was so tough it required being fired three times to properly form that sharp shoulder, designed with PT&G's help. I also knew the load of Retumbo was really a hot one.
With the Savage bolt faces being interchangeable, is it reasonable to get another boltface and convert it to the RWS dimensions for their rim which is a size between a magnum and a standard bolt face? Would you make a ring and place it into the bolt face of a magnum boltface or expand a standard bolt face and adjust the extractor?
I would appreciate you serious and experienced help in this matter. I must admit that back then designing a case capable of magnum ballistics with four cartridges in the magazine, I thought I had done something special back then!

WW

 

[lancetkenyon]

I will just say this.
There are plenty of rebated rim cases out there that do fine at high pressures. 6.5x.284 (or any based of the .284 Norma/Winchester), 6.5RPM, 6.8 Western, all the Noslers (26, 27, 28, 30, 33), all the RUMs and SAUMs, all the WSMs and WSSMs.

That does not mean turning down a rim diameter on brass is safe or not. I don't know.

There are SAAMI cases out there that might get you close to what you are looking for as far as speeds. But I really like Wildcats too. So I understand your affection for your cartridge.

 

[del2les]

Unless I am missing something, I see no issues with turning the rims to standard. I've turned a few rims in both diameter and thickness in my days, and I have never had any issues. However, if you wish to modify a bolt head, that will work also.

 

[can1010]

enlarge the standard bolt head and square the face at the same time. the factory ones are known to be slightly dished. don't worry about modifying the ejector hole i just measured the mag and lapua bolt heads and the distance from center of firing pin hole and ejector are within .005 and the lapua had the shorter distance. PTG used to make custom bolt heads as an alternative to using factory that are good quality and if in stock its ok but ordering might take months and would not be my choice

 

[tobnpr]

How close are you to this?

You are being redirected...

 

[std7mag]

Cutting down the rim would be perfectly acceptable.
Cutting the extractor groove might prove problematic.

I have a wildcat in the works also with a rebated rim.
Problem is that the parent case was done over a century ago and not acceptable to today's pressures.

 

[wildcat westerner]

Hello,
This 300 Hembrook Long is very similar. I have no cases which have not been reduced from the factory rim dimension, mine are reduced to .475
Case diameter at base is. 5.070
Length to shoulder is 2.0940
Length to neck is 2.1953
neck length .300
shoulder angle is 37 degrees
PT&G helped me with neck length and shoulder degree
I have been interested in wildcats since coming across a 257 Ackley Improved and do not know of this Hembrook. Tell me its history.
WW

 

[tobnpr]

Figured it, or something similar had been done before, just looked up the 9.3 x 64 Brenneke on Wikipedia, and scrolled through the wildcats based off the cartridge. It's listed at the bottom.
Search for the Hembrook turned up a thread on the Accurate Shooter forum with the case dimensions. There was apparently brass made for it at one time.

Essentially I was looking at some cartridges and held a 9.3x64 in my hand along with a 9,3x62 (one of my favorites) and a .30-06. It tumbled to me "what if I use the Brenneke brass, but in .30 caliber" so that was the nugget of what I started with. I moved the shoulder forward, made it a 30 degree angle, and took some taper out of the case, to make sure it would not inadvertently be dropped in a 9,3x64 chamber if someone reformed that brass.

So I ended up with a cartridge that fits standard actions, has a 1-caliber neck, and does pretty well for itself. Case capacity is 82 grains of water, so squarely in the range of the .300 WSM and .300 WIN Mag for capacity with similar performance. 165s in the 3350 range with a 26" barrel, that sort of thing.

Both Manson and PTG have reamers available for it. I had Quality Cartridge make a run of correctly formed and headstamped brass. You can also reform 9.3x64 brass. Necking it down creates a false shoulder you can fireform from.

Here is a quick picture
I had Mcgowen make me some barrels. One on a Savage long action and a couple which they fit up to Dumolin Mauser actions. It shoots well:


I disagree with the recommendation to use a standard (.473) boltface. Regardless of what the rim diameter, your bolt thrust remains the same- which is .507 or something close to it; magnum territory. I have a .338 Lapua built off a Savage action, and the bolt lugs are thicker than the standard bolthead. I am pretty certain that the long action magnum boltface also has the thicker lugs; I would use the magnum bolthead and bush as needed for your rim diameter. I would not expect a minor reduction in rim diameter to affect the strength of the casehead, but I'm not an engineer or expert in internal ballistics. It obviously reduces the purchase of the extractor- but if you haven't had a problem with that in the past it would be a non-issue.

That all said, ballistics are only marginally better than the Win Mag (you didn't mention barrel length, Hornady factory ammo is 3130 from a 24" barrel), so you're doing this "just because you can"?

 

[wildcat westerner]

Thanks for this extra ordinally detailed message. As I said I designed this years ago after seeing that four of these cases went into the Savage magazine ( just three in a Remington). My present .300 magnum is a converted .308 Win converted into a .300 WSM on a special Savage target single shot with a short action. Extremely accurate but limited to the single shot and very heavy. The rifle that this new barrel will be added to is a standard Savage switchbarrel and was the original 7.62 RWS I designed long ago. Yep, we are basically doing this because I wanted to and also have a rifle that is more functional and lighter in the field.
All this info on the Hembrook is impressive: properly headstamped and formed brass, reamer availability- wow

WW