BPC for Kraig action

[Bullshop]

Recently I have received in trade a very nice kraig action, a sporter stock for said action, and a Douglas barrel blank that is stamped 405, and 1/14"
I assume that is a .405" bore so likely about a .412" or so groove. I have not slugged it yet.
Anyway trying a factory 405 Win through the action it is rather a tight fit. It looks like to function some steel will have to be removed from the forward portion on the mag area.
For this reason I am thinking something on the order of a 40/50 SS, or a 40/60 Maynard like SPG used early on.
Looking in my cartridge conversion book I do not see a 40/60 Maynard but do see a 40/65 SS that is either the same or must be very similar.
My question, is there anyone here that has any experiance in converting a Kraig action to something like this?

[Don McDowell]

There's a handful of 40 calibers that folks make from 30-40 brass,40-50and 40-70 ss are two that jump to mind, the 4072 winchester is another possible
. Probably the best thing to do would be a chamber cast and then go from there.

[Bullshop]

There is no chamber yet. What I have is just the three rifle components, lock, stock, and barrel.
The barrel is a straight blank about 1.25" diameter.
I think the 40/72 is as long or longer than the 405 so no help there. That's the problem with the 405, just a wee bit too long. I did see one Kraig converted to 405 but the action mods to get it to fit and feed are likely a bit too much for me. That's why I was thinking the 40/60 Maynard. May be just the right length for the Kraig action as is.
I think the 40/60 M uses the 30/40 case full length. I will have to go dig out the Mike V and Steve G book. I think they had it in there.

[Bullshop]

I just went to the Steve & Mike BPC book and I see that the 40/60 Maynard is the 30/40 case pretty much full length.
Then I slugged the barrel and get .4121". They show .408" for the Maynard cartridge but that will still work. I might get away with using 405 dies to load with.
That should make an interesting rifle, a bolt action BPCR. I do have the Buffington type rear sight for a Kraig too. Should even be a good caribou and moose gun loaded to 30/40 pressure with smokeless powder.

[Don McDowell]

If you look at Hogdons web data, the fullhouse 405 peaks out at around 44K . I know you run out of case room with most rifle powders when loading the 300 gr bullets to fit the win 95 action.
There is a version of the 4070 ss made from shortening 405 brass, you should also be able to get a reamer for that using 30-40 brass. If you don't have a set of 405 dies on hand a set of 41 mag will get you by..
If you have the lyman 412263 mould in your collection it's should be a moosemasher of fine quality.
Looking forward to seeing what you come up with..

[Yellowhouse]

Good luck on finding 405 brass unless you already got em.

[Don McDowell]

Sam either Midway or Cabela's had em on sale just the other day.. I got a full box I haven't opened yet, and got lots of it that's been shot and shot and.....

[Bullshop]

As luck would have it I just got some 405 brass from a member here.
I do have a 405 but its a single shot on a B 78 Browning. No problem with the b 78 as I have taken a few moose with it but there is just something about those Kraig actions I like.
I used to have a Ballard rifle in 40/50 and that was a fun little rifle. The 40/50 would likely work too but I would rather use the full length of the magazine, and the 30/40 brass.

[Don McDowell]

I'ld think get ahold of ptg and get the drawing for their 40-70ss on the krag brass and see if you can make the numbers work to go thru the magazine of the Krag.
If you didn't already have the barrel, and 35 winchester would be a nifty thing to do with that krag.

[Mk42gunner]

Dan,

Not much experience with a Krag here, except that the one my best friend's dad has is very slick. One of these days I will find one that I can afford in shootable shape.

I have read that the main problem doing a cartridge conversion on the Kag is converting the magazine to work with the new cartridge.

If I were you; I would make up five or six dummies, get them feeding through the mag and then get a chamber reamer.

Hope this helps,

Robert

[missionary5155]

Good morning
Sounds like an interesting project.
My wonder is how much bolt thrust the krag action is up to...
One thing to be punching 220 grainers at 2000 fps.. but quit another to up that to 300 grains at near the same velocity.

[Bullshop]

Well Sir I know I am not the brightest bulb in the box and there is much I just dont understand but my current thinking was that if it is the same case head and chamber pressure then the bolt thrust is still the same regardless of bullet/boolit weight and velocity. The recoil velocity/energy may change but not the bolt thrust.
Now dont get me wrong! I am saying that is my current understanding, not gospel.
If that is wrong someone please set me straight.

[Don McDowell]

P.O Ackley believed the straighter the case walls the less the bolt thrust. That's why his Ackley improoved cases all have the cases blown out straighter than the parent case along with the 40 degree shoulder.

[bob208]

you could use 444 marlin brass and make a .405 short.

[Bullshop]

bob28
That's exactly what the 40/60 Maynard is a 405 short only it uses the 30/40 case.
Don
Yes you are right about the AI designs and the idea that Parker promoted but even so the pressure is equal in all directions and the case head is still under the same internal pressure as the case walls. The actual stress delivered to the breach face may then be related to the yield strength of the case material to some degree.

[4060MAY]

Bullshop
The 40-60Maynard is not quite a 405 short
the 405 Win aka 40-72 has much thicker brass than the 30-40 Krag blown out to .40 cal. and the rim is thicker. if the 405 is trimmed to allow the magazine to be used the bullet dia would be too small for the barrel you have.
if you blow out 30-40 brass and trim to 2.21 which is just squaring up the case mouth, with a 410dia/400+ grain bullet and the OAL to feed thru the magazine.. the case will hold about 50-53 gr of Black, maybe a little more with Swiss.. a stiff load of smokeless would be a bit much for a Krag action
my 40-60 is on a Danish Rolling Block and the OAL of the cartridge with the RCBS CSA 400, is 2.95, a 300 gr bullet would be shorter

I have a reamer for this but it is set up for .410 bullets with Remington brass for a slip fit...

HTH

[4060MAY]

I meant to add
if your barrel slugs at .4095 like my Douglas
you are welcome to use the reamer..
PM