Home Forums Hunting & Shooting Custom Rifles & Wildcats double radius shoulder?

have any of you seen or done a wildcat with a double radius shoulder like the Weatherby cartridges but on a rimless case? If so I was wondering how they feed, headspace problems, ease of reloading cartridges, etc.? the Weatherby works soo well because it headspaces on the belt, but I am wondering what problems would arise by using a rimless case such as the 30-06 with the double radius shoulder?

thanks!
advntrjnky

I guess my question is.... um, why?

Seems like lots of hassles to me.

I think I've seen one long ago, but it may have been a Weatherby.
Everything imaginable was experimented with in the 1950's-60's.

There is a single radius shoulder recent semi/wildcat:

http://www.rifleshootermag.com/new_products/varminter535_061207/

Bruce

Now, as you are reading this in the Custom & Wildcat forum.....I ask you....Why are you asking why? Can't a guy do research and ask questions for intelectual reasons anymore without getting bashed?

advntrjnky

bcp - thanks for the link! I had forgotten about single radius shoulders....more things to contemplate now.

advntrjnky

Bashed? Hardly the intent.

I still do think that trying to do something on a double radius case that Weatherby hasn't already done is futile and lots of work for minimal return.

But you're obviously free to continue...

More importantly - what does the double radius achieve other than looks? I could swear Roy said he did it mostly to be different. I would like to hear if it actually has an affect on internal ballistics to the positive.

advntrjnky, I think that the double radius proved to be a good deal, right along the lines of what P.O. Ackley came up with with his line of cartridge improvements. The doulbe radius would eliminate case trimming. As for ballistics improvement, that would be very questionable.

If you are thinking of a wildcat improvement, I would suggest that you stick with the tried and proven "Ackley" designs that have a very long track record with guys that like to play around with wild cats(like me).

I was under the impression that Roy Weatherby went with the double radius shoulder because it would be difficult for any old backyard gunsmith to duplicate. Basically, if you wanted a Weatherby, you'd have to go to the source. At least that's what I've read.

keith, could you tell me more about this? I have not found this to be true in my .300 Wby.

Me either.

It didn't eliminate trimming for the several I've used.

That's what I've read as well, for what it's worth.

Second what prairie_goat said. He wanted only bona-fide
gun smiths doing his cartridges at the start.
Cheers Merry Christmas NC

buffybr, Eliminate was the wrong word, "slow down the frequency of Case trimming" would be more correct, sorry about that.

I never trimmed a 257 Weatherby case in two rifles, customs with minimum spec chambers and zero freebore.

The Ackley Improved chambers that I have have eliminated case trimming....so far.

Originally devised by Ralph Waldo Miller and probably others.
Powell (or Payne) Miller Venturi Freebore, PMVF, later became CCC Controlled Combustion Chamberings. The Hollywood gun shop was in the picture and one of the shops was in Ventura so definitely a California development. No doubt a big influence on Roy Weatherby.

Claimed a venturi effect on acceleration of the gas flow, but this sounds like a benefit invented after the fact.

I always went with the view it was to make it harder for reamer makers. But the Germans, Von Hoffe for one, also experimented with various neck and shoulder configurations.

If you could go through all the archives of RCBS, Clymer and Pacific I bet you could find a lot of these single and double radius cases. Some on rimless, rimmed, belted and reformed rimless 348 brass.

Um, the SMC isn't EXACTLY a single-radius. I think Mic and By Smalley (a Thiokol rocket guy IIRC) would beg to differ. The shoulder is shaped to reflect energy in a certain way to help optimize consistent ignition and is deliberately not a pure hemisphere.

Was my 7mm Vom Hoffe Express one of those. It was supposed to have been built by the Hollywood Gun Shop.
Butch

I think there were two versions. One the neck went from radiused to angular after firing if I remember correctly. It was fire formed on each firing. This was abandoned but I don't know if it was just for convenience or if it proved of dubious benefit.

Similar experimentation was down with artillery rounds by the Germans.

Any Photos of the Vom Hoffe?

Just did a search on the 7mm and no wonder I am confused. There are at least four to six versions of the 7mm Vom Hofe.
The 7x66 and 7x73 Super expresses. One radiused the other conventional and the third with the expanding shoulder.
I think all were free bored.

I bought it from one of Russ Haydon's clients. A fellow contacted me and said that he was a friend of the builder[deceased] and really wanted it. I sold it to him for what I had in it. I may have photos of the rifle, but not the ammo. It was the 7X66.
Butch