20 caliber build.

For brass life, I'd lean toward small primer with small flash hole brass. Imo, .223 and 204 cases don't have the capacity to push a 55 appropriately. I run a 20x47L with brass necked down .060" from 6.5 and don't turn necks.

I converted a Savage 110 Predator (204 Ruger) over to a 20-223... very easy to convert the 223 brass. It's just a bushing swap on the die, so two passes to neck it down. The cartridges look great in 20 cal and 55 Bergers. The 24 inch barrel was from Pac-Nor, had a 1-8 twist rate and was shooting 1/4" groups, consistently (using 24x scope).

But there were a couple issues with that built that I messed up on. 1) I went with a straight taper barrel, it was heavy. 2) the cerakote was slightly off and didn't match the receiver, and 3) Savages have a 2 lug bolt, so the 90 degree throw put the bolt handle right up against the scope. For those reasons, I sold it for $1250 and bought a CVA Cascade Varmint Hunter in 204 Ruger 20in, and will be building a barrel for it shortly.

One final comment about loading issues, one of the main reasons I convert 204 Rugers over to 20-223 is that the OACL is about the same, given the 204 Ruger has longer brass and a little stubby bullet, compared to the 20-223 with shorter brass and the bullet seated way out.

btw - I found 0.040 jump was the sweet spot, along with 20.6 gr of IMR 3031. No, this is not an barrel burning overbore like a 20-250 would be, but it will shoot out to 500 yds with 38" drop and has a good amount of energy left at 500 ft-lb... plenty for a coyote at that range.

Happy building! And shooting!

A long time ago Defensive Edge built a .20PPC for me. Bat action, Hart barrel. It's a sweet shooting little rifle. Earlier this year I started developing a load for 55gr Bergers. I got close but I squirreled off into trying to make my 300BLK shoot better, then the 8.6BLK, then back to the 7mm Rem Mag. Eventually I'll get back to it. Here's the last test target, 3 shots at 200 yards, for the .20PPC. There's work to be done. ES/SD needs to be lower and I don't know if the group will repeat. Sure would be nice if it did My sig photo is where I started with it:



I wish that I had gone with something that uses the .223 case. I have a decent stock of .220 Russian brass but, thanks to people that leave their range brass I have an obscene amount of .223 brass.

20 Grendel / 20 ARC is also an option. If you have 250 brass though that really makes sense.

I have a 20GT reamer I just received from Manson. The plan was a short barrel (18ish) 20 cal to shoot the 55gr Bergers and still easily hit 3600 for coyotes. My mind changes almost daily so now I'm not sure I'm going to even use it.

Does anyone have actual H2O case capacity of the 22 ARC vs a 22GT?
Which brass?
Since Alpha makes 6 ARC brass, might try a 20cal in it.

My thinking is - for .20's forget anything over 40 grains, a .204R or .20P will do nicely up to 400 plus on small targets.

My 11 twist .20P has over 2500 bullets fired and is 13 years old and still can hit a pop can at 400. I load - 25-27 grains of either 8208 or CFE223 & now VN540, 40 VMax @ 3650 plus. Last brass buy was 250 pieces of Lake City 5.56. Run bought 1X fired .223/5.56 brass thru .223 small base die, then .223 Redding bushing die with .226 bushing, turn & trim.

Should more bullet weight be needed, step up to a .224 like the .22 CM & shoot the 62 ELDVT or 75 ELDM. More punch at extended ranges over the .20's. My 7.7 twist .22-.250 will shoot 62 ELDVT's just under 3500 using VN 540 - real good buy at LGS.

For me, easy access to brass & small rifle primers keeps my ammo supply up without involved ammo/brass prep.

bfarms said:

I have a good collection of 55gr Berger long range varmit in 20 cal building up. What would be a good case to push them down the barrel? I don't want to get into neck turning. I have enough of that to do. I've thought about building a 20br
But I've heard they can be finicky with feeding, so im up for suggestions. I know very little about 20 cal case options

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Great thread. Thanks for starting it. I'm enjoying the answers.

Justice1327 said:

I've had 2x 20 practicals, 20 BRA, 20GT, and a 20 Creed
20 practical work best with 35 to 40 grain bullets
20BRA works great with the 55 grain
As Does the 20 GT
20 Creedmoor is phenomenal for about 600 rounds.
All were no turn necks.
Depending on what your donor action is, might determine what Brass you choose to build your 20 caliber off of

But honestly, the 55 grain bergers are not that good. Contact me and I'll take them off your hands.

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Do you remember your reamer neck dimensions for the 20gt ? Kicking around having one made.

There's not enough difference in case capacity between the 20 practical, tactical, and 204 ruger to make a difference, stepping up to the -250 case is warranted. I'd imagine at least an 8 twist is needed for that bullet but beware that's going to limit what other bullets you can shoot. I made the mistake of building an 8 twist 20 practical and it'll spin apart the 39 gr Sierra blitzings, only about half of them reach the target. The 40 gr VMax will stay together in it though.

When necking down .223 cases to .20 caliber can donuts form inside as well as outside shoulder area?

Justice1327 said:

Does anyone have actual H2O case capacity of the 22 ARC vs a 22GT?
Which brass?
Since Alpha makes 6 ARC brass, might try a 20cal in it.

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6.5 Grendel is just over 35gr H20 so guessing 20ARC is maybe a gr less. The GT is around 43gr.

Garycrow said:

There's not enough difference in case capacity between the 20 practical, tactical, and 204 ruger to make a difference, stepping up to the -250 case is warranted. I'd imagine at least an 8 twist is needed for that bullet but beware that's going to limit what other bullets you can shoot. I made the mistake of building an 8 twist 20 practical and it'll spin apart the 39 gr Sierra blitzings, only about half of them reach the target. The 40 gr VMax will stay together in it though.

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I was thinking about going with a 8 twist. I don't plan on shooting any other bullets.

I think the 20-250 or 20-250ai case would be the right route on this. There is a guy on predatormasters that has a 20-250ai he has hit coyotes way out there with it. You could google the 20-250ai and maybe it will come up on that forum and you could message him. I was going to do this but went a different route talked into by a gunsmith since there was only a couple bullets that would meet my end result. So I went 22-243ai. Black hole bullets used to make some heavy 20cal bullets also. Also like Vince Mule said make sure the reamer is not saami with lapua brass you will have issues. That happened to me with my first 22-243 barrel.