20 Prac vs. 20 Tac vs. .204 Ruger for AR15

BurnOut

DDOJSIOC
Full Member
Minuteman
Nov 24, 2013
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Dallas
I'm in the planning stages of putting together a 20 caliber upper for prairie dog hunting, and I'm having problems making a decision regarding the chambering:

20 Practical - based on what I can see, this may be the best (of the three rounds mentioned) regarding feed reliability in an AR platform due to the fact that it's a simple neck-down rather than an altered shoulder angle, etc...; no off-the-shelf dies that I can find

20 Tactical - maybe a slight velocity edge over 20 Practical due to steeper shoulder, longer neck, (Lapua) factory brass (supposedly) available, off-the-shelf dies available; possibly not as smooth feeding as 20 Practical

.204 Ruger - available off-the-shelf ammo, available (Winchester) factory brass, probable velocity edge over 20 Practical/20 Tactical due to slightly larger case capacity; slightly longer case leaves less room for bullets that I want to run (Berger 55gr) vs. .223-based 20s

So... what sayeth the Hide? Obviously, the .223-based chamberings have the advantage of a (theoretically) endless supply of once-fired brass available for forming while the .204 has the advantage of offering off-the-shelf (affordable) brass and ammunition (if I forget/run out of hand loads). For the most part, I would expect performance of any of them to be close enough to the others for practical purposes (read: while I would be impressed with a 1/2" group at 500 yards, it's not a necessity).

Is there anything that I'm overlooking?
 
20 PDK, built one for the daughter and love it. 32 grain bullet at 4340 out of 22" and the 39's at 4000. Brass life has been awesome and most live over 10 reloads. Can make out of SPC brass or buy it correctly headstamped. Runs awesome in an AR.
 
I run a AR in 204Ruger and if I had to do it again I would have gone with 20-Pratical just because of the ability to form brass from 223/5.56 brass. Winchester and Remington 204Ruger brass is very hard to come by and Nosler and Hornady brass is way too expensive.
 
arocholl- good reading, thanks!

At this point I'm thinking of going with the 20 Practical for the ease of forming the brass, but I may change my mind (it's already happened countless times). FWIW, I'm also leaning towards sending it to Teludyne for the straightjacket in an effort to allow long strings without overheating the barrel.

Hmmm....
 
I have no experience with the other 2 but I'm running a .204 AR I built for right at $1K with the 24" Shillen with matched bolt and a 15" rail. Filed the feed lips off a couple Pmags and have had ZERO failures in the 500 rounds I put through it (since I fixed the mag problem). While I'm not capable of 1/2" @ 500 yds. with anything, I can do 1/2" @ 200 yds. more times than not with factory ammo. I'm getting 4200 with 32 grain and 4000 with 39 grain. Good luck with your choice and your build.