Barrel length recommendations for .20 Practical

[MBuechle]

I'm building a .20 Practical on the AR platform. Will use a Schneider P5 rifled barrel as I have one on my .22-250 and love it. Looking for recommendations on length. This rifle will see a lot of Prairie dog use. Finished my .22-250 at 27", that might be a tad long for a .20. Also, if anybody has experience on this cartridge in an AR, would you move the gas port down the barrel any?

Mark

 

[mac86951]

Unsure of practical; bit 223 is easier on the brass and easier to load for with a long gas tube (IE rifle length or longer). I also know 223 beyond 24" barrels prefer a +2" gas port, thus longer gas tube as well, not sure why you can't do that on a 24" barrel since an 18" barrel runs rifle length no problem, but I squirreled a little there. I get my +2" tubes from White Oak. I'd think a 26" might make for interesting results.

-Mac

 

[jepp2]

I have a 26" Krieger 223 and a 24" WOA 20 Practical. I much prefer the length of the 24" barrel as it is much easier to maneuver in the field. I use rifle gas systems on both.

 

[MBuechle]

mac86951 - My .22-250 is an AR10, I put that gas port 17" down the barrel, that's rifle length +5" and am quite happy with it. +4" probably would have been enough but this is very easy on brass. I know Gene designed the system to work with a port pressure of 19,000 psi and that as bore gets smaller relative to case volume that point moves further down the barrel. Quickload would help here but I don't have it.

jepp2 - My AR10 with the 27 and Nightforce scope weighs around 13# and it's a bit heavy for a walk around varminter. My son's 16" AR15 is what inspired me to build the .20 Practical, it's so light and handy and is death on Prairie dogs out to 300. So probably want to keep the barrel lighter on the Practical. My .22-250 barrel is kind of a medium palma taper to the gas block, then goes to .730 to the muzzle. Probably do something lighter for the Practical.

Mark

 

[1raggedhole]

Works fine with standard rifle length. Not much gain in velocity, but I like the 26" for added weight

 

[Ledd Slinger]

I have a 20 Tactical AR15 and run a 20" X-Caliber Bull barrel with .936" gas block at rifle length. I get very fast speeds from the 20" so don't really care about anything longer.

20" is usually max length on a full bull AR15 barrel using a .936" gas block. Anything longer and you may gain a little speed, but you'll be sacrificing extra heat dissipation and maneuverability. Can't go full bull on a 24" barrel. I personally think anything over 22" on an AR starts getting unweildy. Just my opinion.

 

[1raggedhole]

I have a 20 Tactical AR15 and run a 20" X-Caliber Bull barrel with .936" gas block at rifle length. I get very fast speeds from the 20" so don't really care about anything longer.

20" is usually max length on a full bull AR15 barrel using a .936" gas block. Anything longer and you may gain a little speed, but you'll be sacrificing extra heat dissipation and maneuverability. Can't go full bull on a 24" barrel. I personally think anything over 22" on an AR starts getting unweildy. Just my opinion.

I have a 26" from white oak, 0.936" gas block, but after gas block is 0.85". Not sure why it is turned down a bit because they use a clamping style block. I went with the long barrel for max speed and max weight. It is a purpose built bench prairie dog ar. Also added 3# lead weight in the a2 stock. Rifle doesn't move and you see every hit!

 

[Ledd Slinger]

I have a 26" from white oak, 0.936" gas block, but after gas block is 0.85". Not sure why it is turned down a bit because they use a clamping style block. I went with the long barrel for max speed and max weight. It is a purpose built bench prairie dog ar. Also added 3# lead weight in the a2 stock. Rifle doesn't move and you see every hit!

Is the barrel free floating? I'm no expert on custom AR15s as I only have one AR with a custom barrel, but I was told I couldn't do a full bull barrel with .936 from gas block to muzzle on anything longer than 20". Well at least not from X-caliber. They said it was due to the amount of weight hanging off of the upper receiver. Made sense to me. Though it seems i was misinformed and you can get large heavy barrel's at long lengths. Thanks for the info.

20" seem's so long on an AR. I just can't see going 26". That would probably feel very odd to me.

 

[JLT]

For your stated purpose, a 24" bull will be fine. You won't lose much in the way of performance with a 22" barrel, but if you're shooting off a bipod or a field rest the extra weight and length of a 24" should not pose much of a problem. A standard rifle length gas set up will work just fine.

The .20 Practical is brilliant on the AR platform. You'll love it!

 

[nmkid]

Good articles on "6mmAR.com"

 

[yotehater]

I'm interested in this also. Was considering a 24" 20 Practical build but have been looking for velocity of different lengths. The 16" carbine barrels are sure easier to maneuver but how much velocity is lost? A 20" mid-length seems practical for it. Compromise with a 22" and rifle port?

 

[1raggedhole]

This is always interesting:
https://www.bullberry.com/204-ruger-velocity-data

Woa uppers are unbelievably accurate, and yes they are free floated. Here is the 204, but they also have 20 practical:
https://www.whiteoakarmament.com/shop/complete-uppers/204-varmint-uppers.html

 

[MBuechle]

Leadslinger - I'm using a DPMS lopro upper receiver, this is a billet upper with about a 1/4" thick walls, it will better support a heavy barrel. It's the upper that Robert Whitley uses on his 6mm AR builds.

1raggedhole - That's great information! That answers my question, probably go with 22".

 

[hogpatrol]

I have a 24" 20P AR from Robert Whitley and I think any longer would just make it unwieldy. I'm using VV133 and dependent on powder selection, doubt there would be much gain in velocity with a 26".

 

[JLT]

I have a 24" 20P AR from Robert Whitley and I think any longer would just make it unwieldy. I'm using VV133 and dependent on powder selection, doubt there would be much gain in velocity with a 26".

I agree completely. I run a 24" and I built a 26" for a neighbor. We did a bit of comparing this past fall over the chronograph and there was no significant difference between the 24" and the 26" with H4198 and 32 gr. VMaxs and perhaps a 15 fps difference between the barrels with the 40 gr. and 39 gr. bullets pushed by CFE223 and 8208 XBR. Definitely a case of diminishing returns.

 

[hogpatrol]

This is a 24" barrel 20P. Picture it with another 2".

 

[Ledd Slinger]

Leadslinger - I'm using a DPMS lopro upper receiver, this is a billet upper with about a 1/4" thick walls, it will better support a heavy barrel. It's the upper that Robert Whitley uses on his 6mm AR builds.

1raggedhole - That's great information! That answers my question, probably go with 22".

Ok, that makes sense. There's not much meat on a standard AR upper.

I was planning on building my next AR on a Spartan non-reciprocating side charging upper. Anyone have any experience with those? I really like the idea of a side charge, especially one that doesn't move.

 

[JLT]

This is a 24" barrel 20P. Picture it with another 2".


View attachment 1001537

Nice lookin' rig!

 

[Ledd Slinger]

This is my 20 Tactical on a Rock River platform with a 20" X-caliber 11" twist 3 groove barrel and RR Match trigger. Same thing as a 20 Practical, just has an improved 30 degree shoulder. The Harrels 4 port Tactical brake adds on another 2+" so total length is over 22". Just don't know if I'd want to go any longer. Like I said earlier, with the right powder, you can get plenty of speed from a 20" barrel. This rifle easily puts 5 shots under 1/2" at 100 yards with multiple loads. I have the front bag rider attachment, but I need to get that rear bag rider stock like hogpatrol has.

 

[hogpatrol]

The stock is a Magpul PRS, early version. The front is something I whipped up real quick out of a piece of delrin. Front and rear ride smooth. My particular barrel works best with 32 Blitzkings and 40 BIBs.