Ive spent some time this winter build a rolling block in 33 caliber with a Green Mountain 1:12 twist #4 profile barrel. Threaded and fit to the reciever, turned 1/2 round and trimmed to 32".  Need to consider what to chamber it in. Originally was going to go with 33WCF,  then considered 33-47.  Then acquired 8# of 30-40 Krag brass and was wondering if there was something  in 33 caliber based on the Krag brass by simply necking it up. Rreamer rental has a 33WCF the others will require having a reamer being made or outsourcing.
But was wondering about a 33-40 Krag.
WW

PTG lists a 33-47 Winchester reamer but I can't find a drawing of it or dimensions. $170. So I'm not sure what the parent brass would be. Maybe need to go back to square 1 and chamber it in 33WCF , reamer rental $60 and ive already formed brass with dies I have. 
WW

You haven't said what the rifle would be used for but, with the barrel weight and length, I would say it would be mostly target work.

If for target shooting, I would not go larger than the Krag case! The 33/47 would be better (32/40-38/55 case) and I shoot a 33 ELCO, it's the full length 357 Max case, necked to 33. I've done well with it, shooting groups as small as .463 @ 200 yards, in a match.

The 33 Win, will be a steep learning curve, getting it to shoot accurately, as there is no loading info, to get you "in the ball park", to start with.

As has been suggested, a 30 cal barrel, would be a better starting point, for your brass. There is loading data for it. I shot my 30/40 HW with some success in matches but, 30/30 would be a better option in that caliber.

Where the 30/40 case, starts to shine, is in 38 and 40 cal.

Frank

I have annother rolling block that has a 40 caliber  barrel thats not chambered that i had considered chambering in 40 Krag/40-60 maynard. That maybe a better choice for the 30-40 brass.
The PTG reamer is listed as 33-47 Winchester , i woundered about the winchester .
WW

I have a similar animal ... a large action Martini that was re-bored and re-rifled by Ron Smith in Alberta to .338/.303 British and it is a tack driver.  (But of course that is to be expected with any of Ron's work.)  Cases are dead easy to fire-form and mine absolutely loves H322 with a 200 grain cast bullet.  Your idea of the .338/.30-40 Krag would be nearly identical, but would have just a bit more powder capacity than mine.  Just my personal opinion, but since you have a large quantity of .30-40 Krag brass I'd do it.  If you're not looking for a competition quality chamber you could use a .30-40 Krag reamer to cut the basic chamber and then finish it up using a .338 neck and throat reamer.  You could neck size formed cases using a .338 Win Mag sizing die (that's what I did until I was lucky enough to buy a used set of actual .338/.303 British dies c/w a neck sizing die).  Easy peasy ...

If you want something larger than 30 cal, but smaller than 38 or 40 cal, the old 30 ARMY (Krag) case could be used to make a shortened version of the 35 Winchester cartridge.

I've got one in a Ruger No.1.  I got a .30-40 Krag reamer from PTG.  At the same time I ordered a neck and throat reamer for .338.  Worked great.  It's been my primary hunting rifle for about 15 years now.  I call it a .33 Krag.  A few years after getting the .338 I ordered a neck and throat reamer for .375, which I call a .38 Krag.  In the .33 Krag with 9X scope I shoot a 225 grain paper patched bullet at 2400 fps.  I also shoot schuetzen offhand with it using a 239 grain smooth sided bullet at about 1400 fps.  Great practice for hunting.  Oh, and a 140 grain SWC loaded with a little fast pistol powder makes a great grouse round at around 1200 fps.  My favorite rifle and cartridge by far.

Doughty wrote on Mar 27^th, 2019 at 7:18pm:


Sounds like a good plan.
Reamer Rentals has reamers. I neck sized some up to 33 caliber with a Lee 33WCF die without any problems.
Thank you.
WW