New builds, 7.62x39mmUSA kinda like a 300/221XL

[kurtz]

Range tested the build for uptown1....

He provided most of the components, we provided the barrel, mags, ammo, and put it all together...

7.62x40mm barrel #001









http://www.ar15.com/forums/topic.htm...f=121&t=381685

[MartytW]

Originally Posted by kurtz

the outside neck diameter of a loaded rounnd with a 125 TNT is .328 to .330, depending what brand of brass you use.....

kurtz

Wow, that seems like a small diameter... my drawings (Ken Howell's book, as well as SAAMI prints) show .253 neck diameter for the .223 Remington. With a .224 bullet that gives 0.029 combined wall thickness (or 0.0145 each) which is in line with the "typical" value of 0.024 (or 0.012 each).

0.328 with a 0.308 bullet gives 0.020 or 0.010 each .... any chance it might be more than that?

[kurtz]

Originally Posted by MartytW

Can you post dimensions of the cartridge? Or a link to a drawing? I am mostly interested to find out the neck diameter. Thanks!

Originally Posted by MartytW

Wow, that seems like a small diameter... my drawings (Ken Howell's book, as well as SAAMI prints) show .253 neck diameter for the .223 Remington. With a .224 bullet that gives 0.029 combined wall thickness (or 0.0145 each) which is in line with the "typical" value of 0.024 (or 0.012 each).

0.328 with a 0.308 bullet gives 0.020 or 0.010 each .... any chance it might be more than that?

the information I have on a .223 cartridge neck diameter shows .247 to .248....roughly 3.8 times smaller than a .458 SOCOM

[pud-knocker]

Originally Posted by kurtz

....roughly 3.8 times smaller than a .458 SOCOM

tooooooo funny eh Marty

[MartytW]

bunch of smarty pants J/K

But seriously, all my drawings show .253
Cartridges of the World, 8th Edn
Designing and Forming Custom Cartridges - Ken Howell (the Blue Book)
Handloaders Manual of Cartridge Conversions (the Green Book)
Norma Reloading Manual
Just to name a few

Reason I asked originally was because I wanted to know if moving the shoulder down the case required a change in case mouth wall thickness. Now I am totally confused ...

[kurtz]

I think as brass manufactures looked for ways to cut costs and manufacturing processes became more accurate (aka: them make more money) we got thinner brass.....I have some older commercial Winchester that the case mouth wall thickness mics right at .014......A new lot of commercial Winchester that I got in last week mics right at .0115 if you check it with a less expensive caliper it rounds up to .012....so, by the time you form it and flow it a couple times it thins quick, and doesn't stand up to as many reloads as it used to.....the brass is still within specs, just on the thinner side of the spec....it's called: quality give-away ( any item sold to a customer above set specifications costs the company more money, meet the minimum spec / make the most money)

[pug]

MartytW my 308R2 cartridge is similar to kurtz except the case is 1.5" long with a .2" neck using .223 remington parent case. kurtz is right on the money saying the loaded necks run about .330" as that is the average.

[kurtz]

pug,

thanks for the back-up....

I posted a little info on another forum about the new round and.....mother fu##er

....my is this....you said this....this is this...you are this....this is better...mine is better...I know this...I read this...

thanks to 320pf for coming to my aid.....

just trying to share what is going on in other parts of the world and people still believe it's flat...I thought someone figured that one out around 1492AD...

Ma can I come home....

Thanks again

kurtz

[320pf]

kurtz,

Check your personal messages on that other site,


320pf

[kurtz]

Have some information for those who have written requesting information on barrels and dies.....

WoooooooHooooooo

John Noveske will be making our barrels for us!!!

A list of barrel combinations we are having made.....

20" SS 1:12 twist polygonal bore mid-length gas system threaded muzzle low profile gas block
20" SS 1:12 twist polygonal bore mid-length gas system crowned muzzle low profile gas block
16" SS 1:12 twist polygonal bore mid-length gas system threaded muzzle low profile gas block
16" SS 1:12 twist polygonal bore carbine length gas system threaded muzzle low profile gas block
16" SS 1:12 twist polygonal bore carbine length gas system crowned muzzle low profile gas block

Also having 30 sets of custom Hornady dies made.....

Thanks,

Kurtz