A buddy has a hex receiver Mosin that has been sporterized with a cut down very rough bore barrel. I can get it for $175 and I’m a sucker for oddball calibers conversions. I know dpcd (Tom), has done several of these. That being the case, what caliber would be a good choice for a simple build without a lot of machine work. My thoughts range from 405 Win to a 35 caliber rebore making it a 35x54R. Maybe a 9.3x62… but it’s not rimmed, so do I need to stay with rimmed cartridges. I remember seeing a Mosin that I believe Tom built on a 405 Grenadier, which I believe is a 7.62x54R opened up to .411 caliber. Now that sounds interesting! BTW… I like putting lipstick on pigs and throwing good money after bad things.

I have built many of them with rimless calibers, and so did Bannerman way back. Just bush up the bolt face. Bend the extractor a bit. You do not need to stay with a rimmed cartridte.
MD has the one in 9.3x62 and has killed lots of stuff with it.
Mosins will take any caliber you can think of; the problem is making them feed. The magazine interruptor does helps nd is an ingenious design, and the mag box will need opening up (as in remove the entire center section) for calibers larger than the original. And open up the receiver bottom; it is shaped specifically for the 7.62.
They are super strong; the entire case is supported; they will take abuse that turns Mausers to scrap steel; and you have seen how I move the bolt handle back to use a real top mounted scope. The center mounted bolt handle hurts them. I use 1903A3 one piece Leupold top base.
No one rule; look at it and make it work. Yes, as close to the 7.62x54 is easiest.

Tom, what do you think about the 405 Grenadier? I like the concept, but can find anything on dies.

45-70 ?

https://www.youtube.com/watch?v=IekTNJDHGB8

quote:

Originally posted by rcraig:
45-70 ?

https://www.youtube.com/watch?v=IekTNJDHGB8

That is a very viable option, except I have a Siamese Mauser that Tom built already and a Marlin Cowboy 45-70.

Re-bore to 9.3x53R?

That would be a great round; dies are always the costly part.
405 Grenadier; another great round; again, dies. Maybe CH makes them...
45-70 is hard to make feed. due to the rim OD. I have built them, single shot.
One of my favorites is a 375 Nitro Flanged; single shot because it is way too long for the mag.

Consider the 375 JDJ. Its a beast. It should feed really well through that Mosin too.

That is a BRILLIANT idea; I just checked; the mag will require minimal modification; open up the front so the big necks will go in.
Open up the receiver in front half of feed slot.
Bolt head and extractor will still work even though the bolt face is bigger than the 444 rim.
I am definitely going to build this. And dies are easy to get, which is a big plus for me and others.
For those who might not be familiar with it; the 375 JDJ is a 444 Marlin necked down to 375.
I have a TC Contender in it.

Didn't a poster on here with the screen name Grenadier design and shoot a wildcat on the 54 case with a 9.3 bullet or is my memory failing me again?

Sounded good at the time----I think!

Hip

A 9.3 on the 54mm case would work fine with the requisite mag and receiver milling out; again, it's the dies that become the issue or not.
I just checked; the 376 Steyr looks perfect; fits bolt face nicely and the mag and receiver can be milled out to make it feed.
More than JDJ.

Found some info on the 54R case opened up to 9.3, i.e. 9.3x54R. Fairly common in Finland, but it offers very marginal increase in performance over the 9.3x57. I’ll rule that out as I already have a Husqvarna in that caliber.

The 375JDJ seems to be a good option as brass and dies are available at reasonable cost.

Tom,
factory 376 (yeah, i know, we don't shoot factory ammo) is high pressure, 63k -

Good point.....

7x65R?

quote:

Originally posted by skl1:
7x65R?

Idk, 11mm is a lot of length that I don't think the Mosin has

Too long, and too small; we want big holes in the barrels, not small ones.
Anyone can make a 7mm.