20 cal. Improved

[SRM]

So
I have a 20 ppc set up for the 50 gen Berger that is no longer with us. The free bore is .05" and is too much for the 55's. I've collected about 1400 55 grn bergers and like my shorter 20" barrel as I run a can .

Has anyone given thought to maxing out this cartridge? I can see moving the shoulder out .05" with a fourty degree shoulder for a little added capacity to push the 55 a little harder.

And of coarse there needs to be a caliber designation. Thoughts?

 

[TAJ45]

Sounds like you need a 20BR, pick your favorite shldr angle.
Orrrr, after speaking with Mr. Unmussig, he said his 47-48 gr would be in the .440 range for BC. $35/hunnert and pick yer boat tail and other parameters. Give him a call. The 55s are definitely weightier but waaay short of the .351BC per Berger brochure.
The Unmussig BC seems high to me but call and verify.

 

[SRM]

I'll look into those . My rifle is set up as a bdl repeater. Have lots of brass. My barrel is toasted.

 

[Wirelessguy2005]

you might want to take a look at the 20 blitz, its a 20ppc ackley improved with a 40 thou freebore, perfect for the 55 berger bullets. I have a reamer if you are interested, shoot me a pm.

So
I have a 20 ppc set up for the 50 gen Berger that is no longer with us. The free bore is .05" and is too much for the 55's. I've collected about 1400 55 grn bergers and like my shorter 20" barrel as I run a can .

Has anyone given thought to maxing out this cartridge? I can see moving the shoulder out .05" with a fourty degree shoulder for a little added capacity to push the 55 a little harder.

And of coarse there needs to be a caliber designation. Thoughts?

 

[SRM]

you might want to take a look at the 20 blitz, its a 20ppc ackley improved with a 40 thou freebore, perfect for the 55 berger bullets. I have a reamer if you are interested, shoot me a pm.

Do you have a print I can check out?

 

[Wirelessguy2005]

I do, it has a .236 neck and was designed to be used with the Norma 22ppc brass, no turn neck design.

Do you have a print I can check out?

 

[SRM]

Found it on smallcaliberclub.com

Cool little round but not quite what I'm thinking. I only want about a .200 long neck with the same body taper as ppc with a 40 shoulder. Bout zero freebore. Be perfect for the 55 Berger.

 

[Wirelessguy2005]

If you are looking for that type of capacity save yourself the trouble and go right to the 20br. Just to be upfront when you use that type of case capacity in a 20 caliber your barrel life is going to relatively short, approximately 800 -1,000 rounds. Also a zero freebore in an improved 20ppc with a .200 neck length doesn't jive unless you want the bullet sitting deep inside the case.

Found it on smallcaliberclub.com

Cool little round but not quite what I'm thinking. I only want about a .200 long neck with the same body taper as ppc with a 40 shoulder. Bout zero freebore. Be perfect for the 55 Berger.

 

[SRM]

I do, it has a .236 neck and was designed to be used with the Norma 22ppc brass, no turn neck design.

That neck should work for 220 Russian just fine. May be a bit much. I do like to clean up necks but three thou would be ok . I have 200 Norma and the heads all need trimming. Rims vary along with od's. Not my idea to rework brass at a buck each.

 

[SRM]

I currently have .05 freebore. Just right for the 50's. Made a gauge from bbl cut and reamer. When I put a 55 in there, it's in the case about .150". That's how I'm getting the neck length and freebore. The short bbl life isn't much of a concern as the pd's here have deminished and I don't want to drive for a day for twenty rounds.

 

[Wirelessguy2005]

What part of Wyoming are you in?

I currently have .05 freebore. Just right for the 50's. Made a gauge from bbl cut and reamer. When I put a 55 in there, it's in the case about .150". That's how I'm getting the neck length and freebore. The short bbl life isn't much of a concern as the pd's here have deminished and I don't want to drive for a day for twenty rounds.

 

[gtl1946]

I'm not up on case designs and capacity but I've got the 20 BR , 20 Nitro which I haven't shot yet , and since you're more up on this than I , how about looking into the 20 Beggs ,by Gene Beggs . It is basically a necked down 220 Russian to 20Cal. . Work?

 

[jcm24m]

What make barrel are you using and also what twist ?? I built a 20 PPC with 8.5-tw PAC-NOR and it is a killer for long range P-DOGS with the 50gr BERGERS!

 

[Phil]

.20 cal. Improved = .20 BR AI / .20 BRDX / .20 Dasher.

 

[SRM]

What part of Wyoming are you in?

North central Bighorn Basin. You around these parts?

 

[SRM]

What make barrel are you using and also what twist ?? I built a 20 PPC with 8.5-tw PAC-NOR and it is a killer for long range P-DOGS with the 50gr BERGERS!

Kreiger 9 twist. Shot really well until I fireformed with cow loads. It needs a new bbl.

 

[SRM]

.20 cal. Improved = .20 BR AI / .20 BRDX / .20 Dasher.

Kind of want to stay with a .220 Russian base on this. How about a 20 Grendel. Wonder if a 30 degree shoulder would contribute to erosion faster. Fourty for a hair more volume. Either way, barrel is a barrel. Accuracy is always more important.
Internal ballistics is almost more than my brain can deal with.

 

[Wirelessguy2005]

I sure wish i lived in Wyoming, I live in Indiana but make a trip out to wyoming each summer to visit friends and shoot pdogs.

North central Bighorn Basin. You around these parts?

 

[GAnderson]

I have the 20 Blitz...it is so easy. Just neck down the Norma 22PPC brass, load and shoot. Extremely accurate, fast and works with a variety of powders. 39gr Sierras really shoot well in an 11 twist. The freebore that wirelessguy quoted puts the base of bullet right at the neck/shoulder junction.

Gene