Playing around forming 7mm cases

[Camba]

I was just scratching my head thinking of the 300 BLK and then neck it down to 7mm.  Just to try it and see, I used my 7mm-08 Rem X-size die without the internal parts of the die and used one of my Lee bullet size plunger that fits in the single press shell holder slot and pushed it in. After I got the neck length that seem the right size, I set the x-size die and I run a few.  Just one struck and it was done without much effort.  Then I thought what about the following:
1.  7mm/300 BLK
2.  7mmx39 Russian?
3.  7mm/30 carbine
4.  7mm/357 mag
4.  7mm/38 spc
Then I stuck a cast bullet that I use in my 7mm-08 Rem and 7-30 Waters to see how they look ("loaded?").  What was very interesting is the fact that I can make any 7mm cartridge in my x-size die as long as the cartridge is equal or smaller case diameter than my 7mm-08 Rem case.  With that in mind, I did the same with the 30 carbine cartridge neck down to 22 cal using my 223 Rem X-size die without the internal decaper rod.
What was nice, is that it is made of one stroke and that neck turning for those smaller caliber made from larges applies.  I am attaching some of the cartridges I created with the x-size die for you to look at, next to the known 7mm-08, 7-30W and a 7mm/223Rem.  Wouldn't it be nice to see how they would shoot in a rifle barrel?
Camba

[gr8ful]

Lol I like the way you think!  I use a hornady 357 taper crimp die to form the shoulder from 30-30 to 357 Herret then trim and full length size.  I hardly ever loose a piece of brass.   Also run my 357 mag into a 32-20 die before sizing to 256 win mag cut my loss rate to 1 in 10

[baranjhn]

I like where you are going with this. Especially the .357 and .38 based cartridges.

[Camba]

..."Also run my 357 mag into a 32-20 die before sizing to 256 win mag cut my loss rate to 1 in 10..."

gr8ful,

I bet if you use a 25 caliber die taking the de-priming rod like I did mine, you may be able to make your 357 mag cases into a 256 win mag in one stroke without loosing any cases.  I don't know what the neck angle is from the 256 wm with respect to a 25-06 or 257 Roberts, or 25 wssm.  Give it a try.  The worse it can happen is that it may not work but if it does, then you got a new way of doing it. 
Camba

[Camba]

baranjhn,

I would love to be able to try the 7mm/357 or the 7mm/38spc.  I would have to guess they will be in the proximity of the 300 BLK, give or take a few fps.  Having the rim will make it a nice contender or any other single shot break open rifle cartridge.
The 7mmx39 can also be a potent short cartridge in 7mm. What do you think about that?

Camba

[baranjhn]

baranjhn,

I would love to be able to try the 7mm/357 or the 7mm/38spc.  I would have to guess they will be in the proximity of the 300 BLK, give or take a few fps.  Having the rim will make it a nice contender or any other single shot break open rifle cartridge.
The 7mmx39 can also be a potent short cartridge in 7mm. What do you think about that?

Camba

I think they could be very similar to a .300 blackout. Currently, my project gun is a BSA Cadet martini that I am piecing together for .300 Blackout based on .357 magnum brass. I am hoping to get everything to the gunsmith to put together next week. If this comes together and works out, I can see something similar being done to another one but in 7mm. I was thinking of using modified 7mm TCU dies that have been shortend for the .357 magnum length. I have been checking GB and Ebay for take-off 7mm barrels and they can be had from $25 to $50 easily.

[geezerbiker]

I like the idea of using the Russian 7.62x39 case with a Ackley style conversion to either 6.5 or 7mm.  While it would be a great shooter, I don't have the resources to make one.

I used to be into more powerful wildcat rounds but with 3 grandkids rapidly approaching hunting age, I've turned my thoughts to youth rifles and the 7x39AI would be a good one.

Tony