7.62x35R (300 BO Rimmed) project

[Flamingo]

This project has been a long time in the works. Some of the dates may be inaccurate because I didn't write them down and I have had some TBI since then.

I have been futzing around with a 7.62x35R project for around 15 years. It all started in 2003 or 2004 when I found a set of Redding 300-221 Fireball brass at a gun show in Tampa for the ridiculously low price of $10. Of course I didn't have a 300 BO of any flavor at the time. I was really into wildcat cartridges at the time and I thought that a rimmed version of the 300 BO would be cool.


I started researching what brass would be best for the wildcat and I initially thought 357 Max was the way to go, but after more research I found out that 360 Dan Wesson brass would be the best bet. I saw that Starline makes 360 DW brass, but it was backordered. No problem, I thought. I placed a backorder and didn't hear anything for 3 or 4 years. Starline sent me a email asking if I still wanted the brass.... I should have said no, but I bought 1K of it. So far the $10 set of dies have cost me an additional ~$150.


The brass came in and I figured out how to form it down to 7.62x35R. It is pretty easy. Lube the brass with Imperial Sizing wax, run it into the Redding 300-221 Fireball seating die with the bullet seating stem removed to start the neck. Then run it into a FL seating die to finish forming the brass. The next step is to trim it to length.

Here a picture of the 360 DW brass, the brass out of the seating die, and the brass trimmed to length.


(This picture is from brass I formed today).


After getting the brass and figuring out that in theory it should work I ordered a Contender G2 frame from gunbroker. I also had a barrel made by a now defunct company called OTT. They used a proprietary method, EDM, of cutting the chambers in barrels. I had them cut the chamber for bullets on the lighter end of the spectrum, and as this was pre-SAAMI for 300 BO they had no issue with that. In hindsight I wish I had gone with heavier bullets in mind. This barrel took close to 18 months to get delivered.

I purchased a stock set from Bullberry and I think it is gorgeous.


Prebarrel thread photo

I recently bought a Omega 36M suppressor and my barrel was not threaded. I took the rifle to a local gunsmith who told me he could get it done in a few months time. After about 4 months I gave him a call, he told me he could not do the work. He had been diagnosed with terminal cancer. I went and picked up the rifle and had a nice chat with the gentleman. I hope I can face my death as stoically as he was doing.

The gunsmith's issues took out some of my interest in this project for a while.

I recently sent the barrel off to Class 3 Machining who got the barrel threaded and sent back to me in a little over a week.

I threw on a SiCo single port mount that I had sitting around and mounted my 36M on it.

Loaded with 110 grain Z max bullets over 5 grains of Trailboss it is mouse-fart quiet.


Picture from today

[awp_101]

That’s awesome! I’ve got a .357 Martini Cadet and something like this should be very doable and very cool should I ever run across another for short money. Or maybe something based on a Ruger No3…

So far the $10 set of dies have cost me an additional ~$150.

#guncranklife

[OlongJohnson]

I recently sent the barrel off to Class 3 Machining who got the barrel threaded and sent back to me in a little over a week.

Nice project! I have the modern, COTS version, which is a CVA Scout in .300 BLK. Stainless, takedown, comes threaded. A little heavier than a Contender, but a lot cheaper.

Thanks for the heads up on Class 3. I've just emailed Morgan. I've been looking at the Scout in .44 Magnum, but all the quotes I've gotten to chop and thread it make the whole thing not make sense.

325gr flat nose at 1050 fps would be quiet and go through a lot of hog meat.

[Flamingo]

Nice project! I have the modern, COTS version, which is a CVA Scout in .300 BLK. Stainless, takedown, comes threaded. A little heavier than a Contender, but a lot cheaper.

Thanks for the heads up on Class 3. I've just emailed Morgan. I've been looking at the Scout in .44 Magnum, but all the quotes I've gotten to chop and thread it make the whole thing not make sense.

He charged me $75.

[Flamingo]

That’s awesome! I’ve got a .357 Martini Cadet and something like this should be very doable and very cool should I ever run across another for short money. Or maybe something based on a Ruger No3…


#guncranklife

I would love a Martini Cadet in 360 Dan Wesson. 250+ grain bullets at subsonic speed with the can would be magic!

[Flamingo]

That’s awesome! I’ve got a .357 Martini Cadet and something like this should be very doable and very cool should I ever run across another for short money. Or maybe something based on a Ruger No3…


#guncranklife

Post a picture of the Martini Cadet. I regret not buying a Cadet at the gun show in Tampa. It was in .218 Bee.

[Flamingo]

Did a test shot in a berm on my property. The 110 Z max bullet over 5 grains of Trailboss (which should be right at 1000 FPS) is quieter than subs out of my 22 LR with a AAC Element can.

[OlongJohnson]

I'm not sure the Z Max will even expand at that velocity.

The bullet you want for that load is the XTP. Engineered for velocity in that range. Perfect for taking pandas out of your trash.

https://www.hornady.com/bullets/hand...9-90-gr-xtp#!/

There's a whole thread at http://www.300blktalk.com/forum/ discussing loads for that bullet in the cartridge. It's a .309, not a .308, but it's so short, and you're putting so little powder behind it, that you don't need to worry about the pressure from swaging it down.

[Flamingo]

The primary purpose for this gun now is quiet coyote elimination. I figure a 110 gr .30 cal bullet at 1000ish FPS will be more effective/humane than a 40 grain .22 cal bullet at roughly the same speed. The longest shot I will take is approximately 75 yards or so,

If I get the Martini Cadet action I will do it in a 360 DW. A 200 grain bullet at 1000 FPS should be even more of a wallop.

[OlongJohnson]

Hornady mentions 1600 fps as the low-end expansion velocity for the 110 V-Max.

https://www.hornady.com/bullets/rifl...10-gr-v-max#!/

The concentricity of the match grade AMP® bullet jacket provides maximum accuracy at all ranges as well as explosive expansion, even at velocities as low as 1600 fps.

It'll probably act a lot like an FMJ at 1000 fps. Although it might yaw and go base-first, in which case it will make a bit of a mess while it's sideways.

1000 fps is pistol bullet speed.