Looking at the 9.3X74 R I don't know how this will work. My original Wesson tipup 44 creedmore is exactly a 40-90 SS Basic with only slight trimming of the rim. That is a .475 straight from back to front (this Wesson is .437 groove and a 2.6" case). If you looka t Wesson cartridges such as the 44 extra long it is similar to this so I wonder if the other 44 Wessons are aso not a true 44 bore. In the absence of an original chamber cast and dimensions at least go with the typical Wesson design of a true straight case which the 40-90 SS Basic is near perfect. If anyone wanted to make an easy Wesson style cartridge design it on the 444 Marlin which is just a bit short and small rimmed. But wouldn't that be a good size case for todays BPCR game? 

Charles

Charles,
That's one of the answers I was looking for - actual straight cases and if anyone had experience with that and if the Wesson's were actually a .446 or if they were something smaller...

Frank,
YES! GM is making a .446 barrel, I inquired before buying and they said:  "Thank you for contacting Green Mountain Rifle Barrel.   The W441736 has a .436”-.438” bore and a .445”-.4465” groove."

I got one in this week, slugged the bore and just like they said it's coming out about .4462 - .4464.    I assumed that I could cut the chamber for this at .472 and get away with it using black but I want to hear about others success or failure.  My other option was making a nibbing die and do the 45-70 stretch thing and make a custom something based on a .45 head and rim but I got a lot on my platter right now and it probably wouldn't get completed until late spring or the next winter.  I'm going to finish the reamer to use 9.3 brass and give it a go.   
Thank guys for the responses.

Made a PP mold for this caliber a while ago so I'll try this.  I picked up a Pressure Trace unit a month or so ago, haven't had the time or cooperating weather to go try it, thinking I'll finish this arrangement and make it the guinea pig.   
Greg

Another update!?
if you need a project that sucks the life and energy out of you - try this -  Not saying that it's much different than many I do but I'm not gaining a lot of ground here quick, there may be a good reason this cartridge had a short life. Finally got everything together, the rifle in a state that would allow it to shoot, the brass to fit the chamber, the extractor in, firing pin functional, stock, etc, etc.  At a 100 yds, with a makeshift scope I use for load development, the 340 gr. greaser was about 2 moa, the 500 gr. PP was 4 moa.  This was with smokeless as I had some time restraints.  Not real impressive yet but more to come.  On testing the wind had died down to about 20 mph, temp was about 20 F and dark was approaching so not ideal either but it had to happen...

I made a sizing die for for the Hollywood press originally - dies for long straight cartridges are a pain - I stumbled on a B&M press as pictured, and for neck sizing, expanding and seating, the dies and punches are simple - more work on this to come...  This is a "Straight" cartridge.  It works out .004" taper from head to mouth and as one can see, I had to "neck" turn for a little clearance.  I fire-formed the cases as previously mentioned and the neck ended up about .011 thick...  Turned them to .0085 and things fit a little better.
Extraction by the high wall is a non issue so I may go in and change my chamber dimension some, I cut it so there was about .008/9" taper and knew the case would eventually shape to the chamber if I was only neck sizing, but with the low pressure loads it will take a few firings?  I'm going to give the neck area a little more room in the chamber, keep my dies the same - minimize some of the case prep.
Greg

I can only imagine - I've done a couple cartridge designs that have been total flops, modified a couple that were a lot of work with little or no gain -just for the experience I guess -that's probably what this is.  Makes me wonder what really happened to come up with the bottleneck, rimless, the rebated rim, belted? what were they really drinking?  Was the brown bottle that prevalent then?    I've got a few ideas from a bunch of us sitting around nursing one - but nothing in a bottle of any kind seemed to help me personally -   
I know the military and conflicts contribute greatly to weapon design but even then it makes you scratch your head and say Hmmm. 

Interesting to say the least......Check out the impromptu scope mount!




JMH

I figured if I showed up at some match with this I'd never hear the end of it  really didn't mean to share this secret with anyone as I tout that iron's are really all there is... (I am stocking up on a few vintage scopes and the materials to make them- as the day is fast approaching that iron's aren't going to cut it)

Hmmm Boring you say well not in the least and from one who has no interest in BP or the cartridge designs so I don't typically respond. But please keep it coming you have surely captured my own interest to say the least and that last target you shot simply impressive and I also admire your work very highly GT and what you are teaching others including myself and what I truly look forward to the most and also can't thank you enough.