7.62x40WT

[popper]

Anyone using it? Seems like the extra grain of powder might be useful. Can't find a chamber dwg anywhere though.

[Moonie]

Wilson Combat should have lots of information for you. It is their propriatary cartridge, it is basically a 300 BO magnum. More powder space in the same AOL cartridge. Different design ideas than the BO.

[popper]

Yea, contacted them and read a bunch on other forums. Still no chamber data. Seems like it is cut for 125gr, I want 140-170 cast. Need to look at the freebore/throat dimensions. WT just gives cartridge data.

[GabbyM]

http://wilsoncombat.com/new/762x40WT-cartridge-case.pdf

That's the case you probably saw. If it were me I'd have a custom chamber cut to retain all the brass for neck length. They cut the neck to use long ogive J bullets. The 150 grain cast FN I'd use would have a shorter ogive and be able to use the entire case length. My Saeco 150gr FN is .880" long. Loaded to the start of a 7.62x40 WT neck that yields a 2.242" long round. If you kept all the brass length it may even crimp in the grove. Question then is would the .180" meplat feed? Sine the Blackout shooters seam to need a pointed bullet. Lyman #311672 sitting here looks like it would work. Or have Goodsteel cut a chamber for there 160 grain project bullet. NOE 310 165Gr. FN 2 cavity GC (30XCB).

Thing to do would be to find a shooter of the WT here to test feed some of these bullets. To see what feeds and what won't.

[popper]

Thanks, I got it from WT yesterday, not proprietary. Looks like they shortened the throat and leade so my boolits will still fit, if I load the 170 deep but it probably won't fit the mag. The 140 & 150 will fit OK. I think it's designed for jacketed 125s (only load data I can find). Got to play with the BO and test some full boat loads to see if the extra case volume is really of any use for me.

[GabbyM]

Just looking at the pressure on the 125 grain loads along with what we know about the 300 BO. I'd be surprised if you could get a cast 150 grain running over 2,000 fps. It may with 45,000 psi loads. 170 grain bullets would be loafing along. It's not like it's rational to expect 30-30 velocity. The heavier you make the bullet the more that small case hurts you in making power. Adding to that is as you stated. Bullet starts to take up powder space as they get longer. I think a case full of AA LT-30 or a fast ball powder under a 150gr cast would be a very useful rifle. Almost a 30-30. I looked at them a few months back but just can't rationalize buying another whole system. Since I already have a lot of guns.

I'd have a little less than zero interest in shooting a 125 grain jacketed bullet from one of these. So trimming the neck so it did not extend past the bullet body to over the ogive would be silly. I'd think standard WT dies would work. Wilson is a custom gun maker. they may chamber the thing the way you want for a little extra. After all it will cost fifty bucks just for a chop saw to cut cases back.

[popper]

Should be able to get 1800 with the 170 & 2000 with the 140 in 300BO, so closer to 1900 & 2200 in the x40 case.Will chrony some hotter BO loads later.

[Moonie]

I get just above 1,800fps with the Lee 155 .312 and 15.3gr H110/W296 in the 300BO. The x40 should do a bit more than that.