20 cal based on 7.62x39 case?

[Striper Slayer]

Has anyone ever heard of a 20 cal cartridge based on the 7.62x39 case?
Say a 20x39.
Thinking that would be a fun AR barrel.
Thanks!
Bryant

 

[X Count]

20ppc. Think there is a write up in the 20 cal cartridge guide on the main page. I've got a reamer sitting there but haven't gone ahead with a build yet!

 

[msalm]

I built a 20 Grendel, same as the ppc w/ shoulder pushed forward. 40gr BIBS in a Howa mini. Great little caliber.

 

[benschott]

20ppc. Think there is a write up in the 20 cal cartridge guide on the main page. I've got a reamer sitting there but haven't gone ahead with a build yet!

yup, but don't try to form the brass as the guide on the main page suggests. It had said to install your 20 cal. bushing in a 22 PPC bushing die. the end of the bushing has a chamfer which prevents the complete neck to be resized. As Redding and several videos have suggested use a full length 20 PPC die to complete the initial sizing.

 

[L.Sherm]

I use a bushing to size down 22PPC brass to 20 cal for my 20PPCAI with no issues. The same as I do with 223 brass for my 20 Prac

 

[X Count]

I use a bushing to size down 22PPC brass to 20 cal for my 20PPCAI with no issues. The same as I do with 223 brass for my 20 Prac

Is it a Redding die though? Redding seem to have a bigger gap between where the bottom of the bushing and the top of the shoulder that some of the Wilson FLS dies.

 

[L.Sherm]

I use a Redding 223 one for my 20Prac and Whidden on my 20PPCAI.
When you neck down from 22 to 20 cal about .030 of the neck becomes part of the shoulder, the neck shoulder junction moves forward.

 

[JohnHenry]

20 ARC ( neck down Hornady 22 ARC)

 

[gunsandgunsmithing]

Can't say for sure on either of these but I find that when sizing 6 Grendel brass using a bushing die for the 6.5, that the bushing can in fact size the entire neck. Reason being, when you neck a case down, the shoulder gets longer, allowing more neck through the bushing shelf. Look at reamer or chamber prints for clarity. Look where the neck shoulder junction is on both the parent and the necked down version.

 

[jackieschmidt]

I would think a regular 220 Russian necked down to 20 cal.would be the best choice.

 

[gunsandgunsmithing]

I would think a regular 220 Russian necked down to 20 cal.would be the best choice.

It's a good one. I shoot the 220 Beggs on occasion...essentially a 220 Russian. It's the easy button and shoots great.

Lots of case taper, as with the x39, which can lead to case stretch and feeding issues in some platforms, like the AR. The case stretch just means you'll need to stay on top of trimming to length but otherwise, not much else. Personally, I like the idea of a 20 Grendel or ARC, as both have less taper and both would be very easy, too.

 

[Striper Slayer]

I was looking at the 7.63x39 case because you can always get brass for that! I wouldn't feel too bad about loosing it in the P-dog fields.
Can you form the x39 to PPC?
I have a 20 BR that is AMAZING! P-dogs on the snow = pretty pictures.

 

[gunsandgunsmithing]

I was looking at the 7.63x39 case because you can always get brass for that! I wouldn't feel too bad about loosing it in the P-dog fields.
Can you form the x39 to PPC?
I have a 20 BR that is AMAZING! P-dogs on the snow = pretty pictures.

More trouble that it's worth and I know of no x39 brass that will hold up to br level ppc pressures, anyway, but yes, it can be formed into ppc brass, fwiw.

Again, Lapua Grendel or ARC brass is where I'd start....or 220 Russian Lapua brass. I don't think they offer the ARC brass yet and I can see why they may never. Lapua is by far the best but other options are available as long as you don't step on the gas too hard with it. Hopefully, the brass issue will resolve in the near future but I'd have to think long and hard before investing in anything I relied on any of the x39 for, and especially at higher pressures. Even the Lapua x39 brass is junk, in my experience. If you're happy at lower pressures, lots of options are on the table.

edit...just re-read your post. At AR15 pressures, lots of options but ARC or Grendel will be the easiest route, I do believe.

 

[Ledd Slinger]

I was looking at the 7.63x39 case because you can always get brass for that! I wouldn't feel too bad about loosing it in the P-dog fields.
Can you form the x39 to PPC?
I have a 20 BR that is AMAZING! P-dogs on the snow = pretty pictures.

You can do it from x39, but you don't want to form brass from 30 cal all the way down to 20 cal, trust me!

 

[Striper Slayer]

Valid points made!
I guess I will stick with the 20 practical in the AR. It's easy. My mind was just looking at the x39 brass wondering.....

 

[Ledd Slinger]

Valid points made!
I guess I will stick with the 20 practical in the AR. It's easy. My mind was just looking at the x39 brass wondering.....

I just put together an AR-15 in 7.62x39. Known as an "AR-47". Not ideal for varmint hunting, but I like have bigger 30 cal bullets in a battle rifle format. Fun to shoot and plenty accurate. If you have a bunch of x39 brass, definitely worth considering getting a 7.62x39 upper as well.

I have also had an AR-15 in 20 TAC withan X-caliber barrel. 20 TAC is basically just a 20 Practical with a 30 degree shoulder. Was a very accurate upper. Posted 5 shot groups under .3's and .4's at 100 yards with 3 different powders during load testing. 20 Practical can produce the same accuracy with a good barrel