What's The Best 20 Caliber Twist Rate ?

FredMcIntire

New member
I'm strongly thinking of ordering a 20 caliber barrel to build a .20 Practical varmint AR-15 for coyote hunting. I have the option of a 24" 1:12 twist fluted stainless steel barrel or an 18" 1:10 twist heavy barrel. I know the 1:10 twist will stabilize up to a 45-grain bullet and the 1:12 twist will stabilize up to a 39-grain bullet. Am I going to regret not going with the 1:10 twist with a .20 Practical ? I can't see shooting a bullet heavier than 39 grains in the .20 Practical. Can I get some feedback, please ?

Thank you,
Fred
 
I would go no less than a 11tw and if a 24in 12tw or 18in 10tw were my ONLY two options I'd go with the 18in 10tw.
 
My 1/12" twist shot the 40 grain Vmax and Nosler Ballistic Tips just fine but shot the 32 grain a wee bit better. Fine with me as 98% of what I shot with it were ground squirrels.
 
How far do you plan on shooting? Those aren't great options imo, I'd want a 22" 1-10 or 1-11 to be sure to shoot the 40's. The 35 is a great bullet though and shoots great in a 12, but has a lousy bc if the wind blows, or the ranges get long. Like said above, the 12 may shoot 39's and 40's, especially the 40 Berger, which would be my pick. I guess pick one, find a load it likes and enjoy. Your ranges probably aren't long in Indiana, so I might lean to the 24", get some 35 and 40 bergers to try and go with whatever shoots best.
 
The default 12" twist has proven marginal with some 40gr bullets, hence the recommendations for 10" or 11" twist. A buddy of mine and I had custom 20Ps built by Dtech and WOA respectively. He ordered a PacNor barrel with 11" twist. I ordered a Shilen Select Match in 10" twist and both rifles shoot 39gr sierras and 40gr hornadys just fine.
 
Originally Posted By: B23I would go no less than a 11tw and if a 24in 12tw or 18in 10tw were my ONLY two options I'd go with the 18in 10tw.

Agreed.

Are those the only two choices? I've got a 1:10 20" .204 standard/H bar contour, and could have had any length and several contours to choose from with BHW.
I'd definitely go with the 10 twist 18" over a 24" for a coyote rig no matter where I was calling.
 
My 204 Ruger upper is 1-11 twist, X-caliber. It's extremely accurate with both the 35 and 40 grain Berger bullets. It's done in the 3/10" range when I'm shooting straight more than once with H322 and IMR-8208. Actually it likes all powders. It suits me just fine. Oh, it's 22", fluted with a JP adjustable gas block and a Noveske free float tube. Upper lapped by D-tech
 
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I assembled my 20p upper using a 22" 1/10 twist barrel. Using either of the barrels you listed, the 24" 12 twist, Berger 35 gr for unsuppressed shooting. If running suppressed go with the 18" and shoot a Nosler 40. My 204r TC Dimension is a 22" 10 twist, I liked how that twist rate worked.
 
So I was thinking of a 20 practical but I can’t see the difference in shooting 40 grain out of a .223 as opposed to a .204? What am I missing here? The load data and velocities on the Nosler site shows they are about identical speed wise.
 
I think unless your going to shoot lighter bullets than 40 grain just load the .223 .It should preform the same as a 20 practical or a 204 ruger
 
I have a 22" 204 with a 1:10 it shoots the 32s fine but I got the 10 purposely to shoot the 40's. It still shoots the 32s just fine but I have noticed more blow ups with those compared to the 40 vmax. I just started reloading so may tinker with some 35's but likely go straight to the 39 blitzkings. Either will likely be fine just find what the barrel likes.
 
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Originally Posted By: 70sdiverSo I was thinking of a 20 practical but I can’t see the difference in shooting 40 grain out of a .223 as opposed to a .204? What am I missing here? The load data and velocities on the Nosler site shows they are about identical speed wise.

I used to run a 204 side by side with a 223 AI in the pdog towns. The 204 is long shot out now but the AI is still going.

Speeds are the same roughly, but results are not. The 20 cal 40 grain vmax has a bc of .28 I think, and the 22 cal 40 gr vmax is about .2. That seems to make a big difference in the wind, and hits are easier with the 204.

But, I built another 26" 223 AI as I got the barrel so cheap I couldn't pass it up. But I would rather have another 204.
 
So, we are talking four different cartridges here. For all intents and purposes,with the 40gr bullet, I would keep the .204 and 223AI as a comparison and the .223 and 20P as a comparison. The .223 and 20P have the same case capacity. The .204 and .223AI have an increased case capacity compared to the othe other two. So, when talking the 40gr bullet, I would agree, that in the .223 or 20P, you see little or no difference in performance. But, when you go to the .204 and .223AI, yes, I would say you are now in a different game with the 40gr bullet. I run a 40 vmax now at 3600fps out of a .223. I would expect to push that a little better/more with the .204 and .223AI, because of case capacity. Hopefully this makes sense. It does in my head anyway
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. Now, with respect to the B.C. between the two 40gr bullets, you will see a bit of difference I would suspect, but I didn't verify the BC's.

Having said all this, I am currently working on a .204 build. I like the 20P concept all around, but for no other reason, I'm going .204 just for the security that it is a factory offering. Meaning that, I do reload, but if I ever get caught short, out in the middle of nowhere, forgot my box of reloads, ran out, lost all of my bullets in a river, ect... I could possibly find some locally to not completely lose a hunt or a trip.
 
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Maybe someone can correct me if i am wrong, but i thought the 204 loaded cartridge was to long for an AR style magazine to fit into. Am I wrong?
 
Originally Posted By: Max LambertMaybe someone can correct me if i am wrong, but i thought the 204 loaded cartridge was to long for an AR style magazine to fit into. Am I wrong?

Remington made a factory 204 AR...204 fits fine in AR 223 magazine.
 
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