What do mean by your 32-40 having to be pushed hard in your 1-12 twist with a 195 grain bullet? That bullet is very well suited to a 16 twist and I think you are over spinning it. My 33-37 was a 15 twist, bullet 234grs.and the avgerage velocity 1474fps. and the best shooting rifle I have owned to date. A 14 twist would also be a good choice beyond that would probably over stabilize that same bullet a bit to much in my own opinion and based on my own experience.

JLouis

That in all honesty I cannot answer so I won't attempt to do so by not having any prior long term experience. I have found over the years from personal experience what should work per the published charts or various stabilization programs often times does not unless first proven. And for personal opinions ending up to being an even less reliable source to go by. If someone isn't already doing it and remaining in the top three consistently in competitive competition I personaly shy away from such unproven advice.

I've bought 2 of those 338 barrels from Green Mountain. The first was turned 1/2 round and trimmed to 32". It was sent to JES and bored to 9.3mm 4 gruve. It's chambered in 9.3X74Rmm on a #5 Rolling block receiver. 
The second was turned the same 1/2 round and trimmed to 32"and left in 338 caliber. The plan was 33WCF on a smokeless rolling block reciever. Another thongth was 30-40 Krag necked up to 338 caliber.  I'm sure it's been done but not what its named. I'll be watching to see what's recommended for the 12 twist. 33-47 is on the maybe list also .
The 338 barrel ended  up weighing 6# 14.5 oz, with 11" octagon and tapered round of 1.02 to .92 at the muzzle. Finished length of 32".
WW

Well we shall see how it goes. I bought two of GMs #4 36" octagon .338 1:12 at todays sale (30% off) so they wer basically $100 each. How could I pass that up? I also bought a 1.25" straight octagon .50 1:24 to build an 1874 50-90 (had one and miss it).

Charles

I would guess that if you are thinking of th .338 oct. for $138 a call to GM might get you one one Monday (For 30% off) since these are a close out item. It doesn't hurt to ask. as of my order there were only 4 left.

charles