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20BR
- Thread starter dirtbiker250
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Just as an aside... for my personal taste I wanted to get that Berger 55 at least 3600 fps or more to make it worth the trouble.
If you do, then you have something special in terms of trajectory and performance. Below that, you can certainly throw the heavy bullet but they don't do anything special till they are sailing out to distance from my view. I can make reliable hits with the 40 VMax at 600 on prairie dogs when the winds allow it, but put that Berger 55 up at above 3600 fps and now we are talking.
To get that bullet up to those speeds is a little hard on the BR cases. Folks have done it but they were standing on it. The BR variants are a little better in terms of pressure, but even a Dasher is pushing stuff like Varget pretty hard. To do this without high pressure, the next steps up include the overbore cases like the 22-250, 6-47, 22 CM, 22 GT, etc. and those do it easily.
The club range where I test is at an altitude of 2650 feet and the two bbls I am running now are a 9 twist and the 55 grain performs beautifully to 1000 yards at 3650 fps with the fireform load. I have several other bbls for the 40 VMax at 12, 11, and 10 twist.
Just for fun I'll snip in a snapshot of the wildcat's ballistics for the fireform load at 3650 fps I ran in Wyoming this year.
Good Luck with your project and in for the range reports!
If you do, then you have something special in terms of trajectory and performance. Below that, you can certainly throw the heavy bullet but they don't do anything special till they are sailing out to distance from my view. I can make reliable hits with the 40 VMax at 600 on prairie dogs when the winds allow it, but put that Berger 55 up at above 3600 fps and now we are talking.
To get that bullet up to those speeds is a little hard on the BR cases. Folks have done it but they were standing on it. The BR variants are a little better in terms of pressure, but even a Dasher is pushing stuff like Varget pretty hard. To do this without high pressure, the next steps up include the overbore cases like the 22-250, 6-47, 22 CM, 22 GT, etc. and those do it easily.
The club range where I test is at an altitude of 2650 feet and the two bbls I am running now are a 9 twist and the 55 grain performs beautifully to 1000 yards at 3650 fps with the fireform load. I have several other bbls for the 40 VMax at 12, 11, and 10 twist.
Just for fun I'll snip in a snapshot of the wildcat's ballistics for the fireform load at 3650 fps I ran in Wyoming this year.
Good Luck with your project and in for the range reports!
He told me he was right at 3600 with the 55’s. His is a 9 twist at 26” and said it’s def enough to stabilize em. We are at 6300’ also. I ran the 55’s at 3600 compared to my 22Cm at 3470 with 75 Eld’s. And they are identical in drops to around 700. 55’s little bit more wind deflection of course. But lots less powder and even less recoil than the 22Cm , which is already mild. At best I’ll have a laser 20 cal that’ll shoot both bullets well and fast. If I can’t get the 55’s up there around 3600 then I’ll still have something that shoots the 40’s a bit quicker than my current 204 setup.
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Someday... if these European wars ever end... we will start seeing RE15 and TS15.5 again...
ETA: in the bottom right corner of my header block, you will see for the 1:9 twist the SG = 1.41 which is pretty good.
ETA: in the bottom right corner of my header block, you will see for the 1:9 twist the SG = 1.41 which is pretty good.
I’ve been trying to talk him into building himself a 22 creed since he build mine for me . Best coyote rifle I’ve ever used. I killed 2 on one set across a river at 743 and 755. And last winter I got one at 871. He keeps arguing the 20BR with 55’s is similar. Yeah it’s pretty similar if the speed is up. Plus less powder. So I’m going for it LOL. Something new to play with anyway. I had a fast 204 barrel several years ago that sent 39’s at 3910 with 8208 and it was super fun on ground squirrels and pdogs. 40’s even faster would be slick!!
I built mine on an Impact NBK with a 26” 9 twist and it shoots the 55’s really well at 3660fps with 32.3gr of RL17. I haven’t tried any other powders because it shot so well with RL17. I killed my first Coyote with it last year at 602 and just missed one (wind call) at 1380 that hung up and was sitting looking at me…so the 55gr Berger bullet is up to the task!
With Varget, H4895 and 8208XBR I'd start at 27gr and go up in .3 increments until you have ANY sign of pressure and then back them off .5 and see how it groups
With N133 I'd start lower at 26gr and do the same
I have my bullets seated just barely off of the lands
Good Luck, let us know how it goes!
Hopefully won’t be too long and I’ll get to start testing!
Yes
It feeds great from an AW mag with the HRD kit in it...I'm running a Hawkins bottom metal with the AW mag latch
The BR case can do it but it beats up the brass, the Dasher and BRA can do it with a little less pressure/stress, and those other cases do it with more case volume, lower pressure, and other powders.
The 20-250 was done many years ago. It just has leftover case volume.
The GT case is just about right, but I haven't personally run it yet. I'm going to get started on the reamer and bbls while I burn up the bbls I have now for the CM variant and then change.
The 20-250 was done many years ago. It just has leftover case volume.
The GT case is just about right, but I haven't personally run it yet. I'm going to get started on the reamer and bbls while I burn up the bbls I have now for the CM variant and then change.
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