Barrel suggestion 18/20"

snax

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I want to do a 18 or 20" build.
I have 5.56 in 16 and 10.5.
And 300blk in 10.5
Anybody got a long barrel in 300blk or is it not worth it for that caliber.
I have/had barrels in steel and stainless from BCM, Andersen, Bear Creek, CMMG, and Bushmaster.
All seemed similar in quality and performance.
There are some silly deals out there now.
What kind of experiences/recommendations does anybody have with the longer barrel platform?
 
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Only reason i can see to go longer for 300blk is for sight radius if your running irons or trying to get the most velocity.
I figure you need to find out at what length is the powder charge/gas no longer accelerating the bullet...at That'd point you dont need a barrel longer than that.
Also highly dependent if your lobbing heavy and slow or light and fast.
 
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Why not try something new and different? How about 24 or 26 inch? 20 Practical?

I am VERY interested in this caliber, either for bolt or AR type rifle. That, or the .17 WSM or .17 Hornet, or maybe .17 Fireball.

Anyhow, some articles:
Barrel length recommendations for .20 Practical

20 Practical AR "Ultimate Varminter"
Warren's 4200 FPS "20 Practical"
THE ECONOMICAL 20 PRACTICAL « Western Powders
The 20-Caliber Black Rifle — AR Chambered in 20 Practical « Daily Bulletin
20 Practical - A Potent, Accurate Varmint Cartridge, Based on the .223 Rem | OutdoorHub
.204 vs. .20 Practical vs. .20 Tactical - PredatorMasters Forums

Some barrels:
Shop New .20 Practical Barrels | .20 Cal. Barrels
20 PRACTICAL | 1X10 | 22" | CONFIGURABLE (only 1:10 twist though)
https://www.midwestgunworks.com/page/mgwi/prod/mgw-20p-match-flbbl

20pracuppers.jpg

20pracsbys72.jpg


Samples of 5 shot group at 100 yards:
5_shot_group__2.jpg



25 gr. H335 with Berger 40 gr. BTHP bullet - 3575 fps.
26 gr. H335 with Berger 40 gr .BTHP bullet - 3740 fps.
27 gr. H335 with Berger 40 gr .BTHP bullet - 3846 fps
 
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Why not try something new and different? How about 24 or 26 inch? 20 Practical?

I am VERY interested in this caliber, either for bolt or AR type rifle. That, or the .17 WSM or .17 Hornet, or maybe .17 Fireball.

Anyhow, some articles:
Barrel length recommendations for .20 Practical

20 Practical AR "Ultimate Varminter"
Warren's 4200 FPS "20 Practical"
THE ECONOMICAL 20 PRACTICAL « Western Powders
The 20-Caliber Black Rifle — AR Chambered in 20 Practical « Daily Bulletin
20 Practical - A Potent, Accurate Varmint Cartridge, Based on the .223 Rem | OutdoorHub
.204 vs. .20 Practical vs. .20 Tactical - PredatorMasters Forums

Some barrels:
Shop New .20 Practical Barrels | .20 Cal. Barrels
20 PRACTICAL | 1X10 | 22" | CONFIGURABLE (only 1:10 twist though)
MGW AR-15 Stainless Steel Fluted Match Barrel, .20 Practical

20pracuppers.jpg

20pracsbys72.jpg


Samples of 5 shot group at 100 yards:
5_shot_group__2.jpg



25 gr. H335 with Berger 40 gr. BTHP bullet - 3575 fps.
26 gr. H335 with Berger 40 gr .BTHP bullet - 3740 fps.
27 gr. H335 with Berger 40 gr .BTHP bullet - 3846 fps
1/10 is most likely plenty fast enough. Toss some of those sub 40 grainers at 3600+ fps down a 1/9 or faster and they probably go POOF at 30 yards...
 

widnerkj

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Eh... the blackout is supposedly designed around an 8” barrel. As in it burns all the powder within that. I guess you could get some extra velocity going longer, and the longer sight radius is good for irons. But I haven’t felt myself wanting much more out of my 8” .300 blk.
That said, just going for fun..... Alexander arms does have a 17HMR AR upper. Which was the only rimfire ammo I could find during the Obama ammo drought. So that’d be pretty handy.
I’d avoid the 224 Valkyrie, as the guy that stole it from Jimmy Slone changed the neck angle enough to get around copyrights, but it’s blowing primers badly.
The 6.5 Grendel is pretty awesome, ignores wind really well, and since 6.8 mags work, and can be found in MA, that’d be a good 18” bet.
I just did a dedicated .22lr 16” upper, that I HATE! Because it’s so ammo sensitive.
 
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edmorseiii

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Anybody got a long barrel in 300blk or is it not worth it for that caliber.

I have a 16" 300blk upper that I take for walks during deer season and I surely wouldn't go any longer, even now it feels like a broomstick. Now that I am starting the eForm1 on my MCX, I'm going to do a 9" 300blk upper with suppressor handguards to tuck my can, and that will most likely be my go to gun in the fall.
 

widnerkj

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18” to 20” is LONG for a .300 blackout. That was the original question.
 
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