7.62x40wt Brass

[Tim Singleton]

Carolina Brass is gearing up to produce WT brass. It's hard to find.
They sell LC 223 brass as well as make 300 blk out brass

carolinabrass.net

 

[jscandale]

How is the WT different than the .300 blk?

JS

 

[Tim Singleton]

I have both. The Wilson is 5 mms longer. It was designed to get a little more performance with the lighter bullets (110,125) than the blackout. The Wilson barrels are 12 twist and throated for the lighter bullets.
Mine runs the 125 gr bullets at 2550. 20" barrel
Some guys who don't care anything about subsonic loading and want the most power out of there AR with a .30 caliber bullet based on the 223 brass really like it. I'm one of them.
I make my own brass same procedure as making blk out, only longer.

Brass is hard to find already processed. That's why I wanted to let people know of a reasonably priced source.

My blackout is throated and twist to be able to shoot the 220 grain bullets. So accuracy is not that great with the 110 or 125

http://wilsoncombat.com/new/762x40-project.asp

 

[Tim Singleton]

JS
I've been reading on your site I really want a side charger for my next build.
I don't have a 6mm AR yet.

 

[rcw3]

Brass dimensions:
Overall case is 1.565" vs around 1.365" for 300 BLK
Shoulder is a little fatter in dia. for 7.62x40wt
Neck length is around .203" vs around .270 for 300 BLK

Personally I like the 7.62x40WT over the 300 BLK, but that's just me talking and I am mainly into supersonic loadings too. Seems like Wilson did the most they could with the 223 case and making a 30 cal. out of it. The 7.62x40wt gives up about 8 gr of water weight to the 30 ARX but is about 5 - 6 gr. greater in capacity than a 300 BLK.

Robert

 

[Tim Singleton]

I've had mine for about a year. If I was building a .30 cal AR today. I would definitely look at the 30ARX.
I would still have to weigh it against the Wilson with the 223 based brass, not having to change bolts and magazines.
But power is power

 

[rcw3]

Tsingleton

I have some unfired 7.62x40wt brass made from .223 brass so I estimated the water capacity based off the unfired brass I have, because the brass blows out a little in diameter at the shoulder when you fire it. The unfired brass I have is about 28 gr. water capacity and I figured when you fire it, it would be around 29 - 30 gr water capacity.

Do you happen to have a measured water capacity for brass that has been fire formed?

I would be interested to know what you get if it's not too much trouble.

Robert

 

[rcw3]

Tsingleton

FWIW - - I am also working with a 40ËšImproved version of the 30 ARX (i.e. shoulder blown forward and 40Ëšshoulder vs the 30Ëšshoulder of the base 30 ARX case. I just don't have all the data compiled to do up a web page with chrono results, etc. for the 40ËšImp. version yet.

Robert

Here's a pic of the two for reference:

 

[Tim Singleton]

I've never measured the h2o capacity. I'll try to do that tomorrow

 

[Tim Singleton]

Tsingleton

FWIW - - I am also working with a 40ËšImproved version of the 30 ARX (i.e. shoulder blown forward and 40Ëšshoulder vs the 30Ëšshoulder of the base 30 ARX case. I just don't have all the data compiled to do up a web page with chrono results, etc. for the 40ËšImp. version yet.

Robert

Here's a pic of the two for reference:

That 40 degree shoulder is awesome. What is the water capacity of it? Do you think it will perform at 30br velocities?

 

[rcw3]

Tsingleton

Great - thanks! Working off a 223 bolt and 223 brass, it seems like the 7.62x40wt gets about what there is to be gotten out of that set up - - neat cartridge for sure!

Robert

 

[jscandale]

I am somewhat interested in the (some) .30 cal AR based cartridge of some sort. Why, I don't know...I can't hunt in PA with it, however I would like to take a trip to TX for a hog hunt. Whitely's 40° version looks pretty cool, but I am not a taker of the .443" bolt face in the AR, mainly because they don't make one in LH. I have gotten to the point in life where I just refuse to shoot a right handed gun dang it! I may have to develop one on the 6.8 case just fer fun.
I made a sizing/trim die for a Dillon trimmer about a year ago which will allow me to produce about 600 .300 BLK cases per hr from .223 brass. Again, I don't know why, I don't have a .300 blk, but have built several for customers.
I too, am not interested in shooting expensive heavy bullets at a subsonic speed through a suppressor because I am pretty sure that I am probably not going to get a phone call from Seal Team 6 any time soon to lead them into a clandestine mission, so I would go after terminal energy at any decibel level.

JS

 

[Tim Singleton]

I too, am not interested in shooting expensive heavy bullets at a subsonic speed through a suppressor because I am pretty sure that I am probably not going to get a phone call from Seal Team 6 any time soon to lead them into a clandestine mission, so I would go after terminal energy at any decibel level.



That made me spit my coffee HA Ha He
Exactly what I felt when I built my Wilson. I wanted the most 30 cal power I could get in my AR it really is a semi auto 30-30 now.
I will probably sell my blk out upper

 

[jscandale]

Does anyone make a .30 cal version of the 6.8 spc case yet? I'm sure someone has. I'd like to develope one but don't want to reinvent the wheel. Also, I wonder if a 7mm version has been developed. It's so close to the 6.8 that it may not be practical though. Just thinking out louud here.

JS

 

[ebb]

I did a short search and found some people talking about left handed 6.5 grendels and 7.62 -39 uppers. Either of these should give you the left handed bolt with the .443 bolt face or PPC bolt face. I bought a Hall bolt action bench rest rifle to have something to shoot with my friends as they are all bench rest people. When the 6PPC barrel is toast it will be a 30 PPC, they have barrel life that is as good as the 30 BR I am told. Many are claiming 8000 -10000 rnds with the 30 BR. I don't know if the 30 PPC would feed in an AR but all of its other qualities are great. This chambering has all I am looking for and what ever its name 30PPC , 30 AR or ARx it all looks real good. The world record was just broken with a 30PPC.

 

[jscandale]

What world record? It seems like every week " the word record " gets broken.

JS

 

[rcw3]

Tsingleton

FWIW - If you have a 300 BLK upper/barrel, there is no reason why it cannot be re-chambered to a 7.62x40WT or a 30 ARX, etc. with no barrel set back tweaking required (i.e. use the same barrel extension, extension threading, etc.). The only item that may (and that's may) need to be addressed is a bushing down of the port if the 300 BLK port was set up for subsonic loads and is real big for the length of the gas system involved. John Scandale (Keystone Accuracy) is pretty adept at this type of work and has a shop that can certainly handle such a job - - whether he's game to do it, I don't know.

Robert

 

[GSPV]

What world record? It seems like every week " the word record " gets broken.

JS

http://bulletin.accurateshooter.com/2013/08/mike-stinnett-breaks-the-unbreakable-record-with-0077-group/

It's not a 30 PPC. It's a 30 Stewart. It's a development of Ralph Stewart's old Sako brass 6 PPC chamber design.

Mike did not luck into that group. He's been winning a lot with that cartridge.

 

[jscandale]

Wow, .0077"! I don't know a thing about bench rest, but I don't think you need to know a thing to know that's pretty amazing.

JS

 

[GSPV]

With the introduction of LT-32, Larry Feusse's 30 Gorilla and Robert's 30 ARX 40 improved are very interesting in a bolt gun. My best load in my 30 Major benchrest rifle is 34.7 gr of LT-32 pushing a 115 gr 10X custom bullet at 2953 FPS. It is, however, a PITA to load. Even at a dead slow trickle, it completely fills the case. Would love to get the powder column about 1/2 way down the neck so that the bullet just seats on top of it.

Disclaimer: I don't know anything about an AR. Just started shooting one in a deer/predator context.

But, in my 30 Major AR, cut with my 30 Major benchrest reamer, I have space left using all the H4198 that I care to use pushing the Speer 125 TNT. I expect that it would be the same in the standard, I.e., not the 40 deg improved, 30 ARX with similar bullets.