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What 20 caliber ….

nakneker

Gold $$ Contributor
I’ve been building a lot of fun rifles as of late or I should say “Zack has been doing the building”. I’ve been having fun with wildcats, the simple variety where a guy just has to neck down a case, load and shoot. The latest were a 22-6.5 PRC and a 22x47 which kind of led me to this post. I want to build something to shoot the Berger 55 grain 20 cal bullets I have. Currently I have a 20-222, 20 PPC and a 204 but for the 55s I want something with more boiler room. Being able to feed from a mag is a priority.

I’m thinking I may order a reamer for a 20-6GT. I’ve seen a couple 20 BRAs mentioned here among others but I’m not sure how they would feed. Anyways, do you have any input to share or think about?
 
Something that not only has good brass but also available good brass. I like my 20-250 but probably wouldn't recommend one unless you already had some new Lapua 22-250 brass sitting on the shelf.

Alpha makes 22GT brass and necking that down to .204 would make for a pretty slick and easy one. If you wanted to go with something that had even more case capacity a 20 Creedmoor would be another easy peasy one with top quality and always available brass.
 
I’ve been building a lot of fun rifles as of late or I should say “Zack has been doing the building”. I’ve been having fun with wildcats, the simple variety where a guy just has to neck down a case, load and shoot. The latest were a 22-6.5 PRC and a 22x47 which kind of led me to this post. I want to build something to shoot the Berger 55 grain 20 cal bullets I have. Currently I have a 20-222, 20 PPC and a 204 but for the 55s I want something with more boiler room. Being able to feed from a mag is a priority.

I’m thinking I may order a reamer for a 20-6GT. I’ve seen a couple 20 BRAs mentioned here among others but I’m not sure how they would feed. Anyways, do you have any input to share or think about?
Well, there certainly is no substitute for cubic inches. What about a 20-250? For a 55gr .20 bullet, there ought to be enough gas in that tank to move that little pill along.
Brass availability might be an issue....I have not seen any 22-250 brass in a while. Otherwise, you are limited to what brass you can get your hands on.
 
Well, there certainly is no substitute for cubic inches. What about a 20-250? For a 55gr .20 bullet, there ought to be enough gas in that tank to move that little pill along.
Brass availability might be an issue....I have not seen any 22-250 brass in a while. Otherwise, you are limited to what brass you can get your hands on.
I have a good stash if 22-250 Lapua brass for my 22-250 AI, I’m thinking GT or BR variant for this one. Not sure I need the most powder capacity just enough to fling those 55s at a respectable speed. The 20GT is attractive with Alpha making 22GT brass. I’m using that brass in my 22GT and think highly of it. Neck it down and shoot.
 
I have a good stash if 22-250 Lapua brass for my 22-250 AI, I’m thinking GT or BR variant for this one. Not sure I need the most powder capacity just enough to fling those 55s at a respectable speed. The 20GT is attractive with Alpha making 22GT brass. I’m using that brass in my 22GT and think highly of it. Neck it down and shoot.
.20 GT would be very cool! And no need to run it flat out for very good speed. Should feed great and be something that very few will have. I see no down side and another very fun build. Go for it bud.
Paul
 
If you’re going big (20 Creedmoor), it’s probably worth simulating in GRT or Quickload to make sure you don’t end up needing a weird burn rate (e.g. 4831 is too fast and RL23 doesn’t work well as a theoretical). I saw this when modeling a 222 and a 221 fireball shooting the 90SMK. The 221 was 200fps slower with only 2gns less powder because it fell between H4198 class and the Benchmark class of powders. Let me know if you would like me to play with something in GRT for you.
 
If you’re going big (20 Creedmoor), it’s probably worth simulating in GRT or Quickload to make sure you don’t end up needing a weird burn rate (e.g. 4831 is too fast and RL23 doesn’t work well as a theoretical). I saw this when modeling a 222 and a 221 fireball shooting the 90SMK. The 221 was 200fps slower with only 2gns less powder because it fell between H4198 class and the Benchmark class of powders. Let me know if you would like me to play with something in GRT for you.
Thanks Evan, I may take you up on that offer, it’s appreciated!
 
Look at the 20 primal. Primal rights has a good video on it on YouTube.
I was watching his primal cartridges, kept waiting for the 22 primal to move forward. He made some videos on the primal cartridges last year, announcing what they had come down the line but I never did see anything but the 6 primal actually move forward. I might be wrong. I think the 6.5PRC case is bigger than I’m looking for though, at least for 20 caliber.
 
Thanks Evan, I may take you up on that offer, it’s appreciated!
I think a 20 Dasher or 20 GT is probably at a limit where extra powder is resulting in a disproportionately smaller amount of speed.

The 55gn Berger is a phenomenal bullet. My 20 Vartarg is a 9 twist and shoots them at ~3100fps. It has teased 1.25” groups at 600 yards on many occasions. I know a handful of guys were campaigning 20 BRs in 600yd BR with the 55gn and getting great results.
 

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