Ultra-short 300 blackout's in review NEW UPDATE: Third Article page 3 - Page 2

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[ARCHIVED THREAD] - Ultra-short 300 blackout's in review NEW UPDATE: Third Article page 3 (Page 2 of 3)

Posted: 7/17/2018 8:44:38 PM EDT

[#1]

Bump for update.

Posted: 7/17/2018 8:53:01 PM EDT

[#2]

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Quoted:
Finally fired mine yesterday. 6.5" V7 barrel shooting factory Hornady 110 gr Vmax. Only shot 5 rounds down the barrel, I don't have any sights on this sumbitch yet. Checked for function, everything was good. Chronographed 2 rounds. Velocity was 2034 and 2061. 2100 fps should not be that hard to attain with handloads hopefully. I'll check accuracy next.

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If those are typical velocities for that short a barrel then I just changed my mind about 300BO. I assumed that shorty would be around 1800fps.

Posted: 7/17/2018 9:34:06 PM EDT

[#3]

Quote History

Quoted:
If those are typical velocities for that short a barrel then I just changed my mind about 300BO. I assumed that shorty would be around 1800fps.

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Quoted:

Quoted:
Finally fired mine yesterday. 6.5" V7 barrel shooting factory Hornady 110 gr Vmax. Only shot 5 rounds down the barrel, I don't have any sights on this sumbitch yet. Checked for function, everything was good. Chronographed 2 rounds. Velocity was 2034 and 2061. 2100 fps should not be that hard to attain with handloads hopefully. I'll check accuracy next.

If those are typical velocities for that short a barrel then I just changed my mind about 300BO. I assumed that shorty would be around 1800fps.

That was my assumption as well. I was pleasantly surprised at those velocities with factory ammo. Looking forward to seeing what reloads can do.

Posted: 7/20/2018 12:48:05 PM EDT

[#4]

No update of worth, had a big range day with camerman and all, cancelled due to heat. Left town for a few days, just got back, working on scheduling first range day before triggercon.

Also still waiting on Veritas/slr upper and Mc6-sd

Fiocchi sent 250 subs though, so theres good news there

Posted: 7/21/2018 3:39:06 PM EDT

[#5]

So I shot a Sig Rattler today and the compact size is damn nice. What advantages other than being piston driven does the Sig offer that a 5" AR platform doesn't? Other than obvious cost and cool factor and as we all know looking cool is the most important thing.

Posted: 7/21/2018 4:29:31 PM EDT

[#6]

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So I shot a Sig Rattler today and the compact size is damn nice. What advantages other than being piston driven does the Sig offer that a 5" AR platform doesn't? Other than obvious cost and cool factor and as we all know looking cool is the most important thing.

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Ability to quickly/easily change to another barrel length/caliber (Rattler is just a “mini” MCX chassis)

Ability to quickly/easily change handguard

Ability to quickly/easily change stock

5.5” Rattler will be shorter than 5.5” AR, since there’s no buffer tube and a Law folder adds length.

Posted: 7/29/2018 9:01:23 AM EDT

[#7]

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Ability to quickly/easily change to another barrel length/caliber (Rattler is just a “mini” MCX chassis)

Ability to quickly/easily change handguard

Ability to quickly/easily change stock

5.5” Rattler will be shorter than 5.5” AR, since there’s no buffer tube and a Law folder adds length.

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Gotcha.
I did get an email from BA about their new 6". For the price I'm really considering it.

Posted: 8/2/2018 11:33:13 PM EDT

[#8]

first range day complete. quick info dump, details will be in the article. very tired, no grammar editing tonight.

at 50 yards, 4x optic, standard weight carbine buffer, 3 ammo types, barnes 110 ttsx, federal copper 120 gr, fiocchi 220gr subs

1" at 50 is 1.9 MOA

R2B shot 1.3" to 2.3" groups (the 2.3" had a called flyer, would have pushed it to 3.78". I shanked it totally).

V7 shot .85" to 2.4" groups. the .85" had a called flyer, out to 1.83" if included. next best group was 1.25"

r2b preferred the federal copper for 1.3" and 1.8" groups

v7 likewise posted best groups with federal, .85" and 1.25"

r2b didnt cycle subs without can
v7 cycled subs but didnt lock last round

subs were the worst groups for both guns, by a good margin. in the article I may tally totaly for supers and subs seperately.

will try to get velocity data posted tomorrow. shot barnes rangeAR through chrono as well, not enough on hand for groups

Posted: 8/3/2018 4:14:54 PM EDT

[#9]

velocity data 70 deg F:
barnes rangeAR 90gr
v7 2154, 2164, 2195, 2111, 2207
r2b 2116, 2070, 2110, 2116

barnes ttsx 110gr
v7 1975, 1961, 1972, 1978, 2001
r2b 1917, 1916, 1937, 1920, 1925

Federal copper 120gr
v7 1779, 1799, 1798, 1792, 1802
r2b 1735, 1739, 1723, 1732, 1748

fiocchi 220gr
v7 797, 798, 828, 806, 824 cycled unsuppressed, no lock back
r2b 838, 828, 849, 822, 838, did not cycle unsuppressed

Posted: 8/4/2018 1:47:13 PM EDT

[#10]

Thanks @withoutremorse42 for this information!

Posted: 8/5/2018 7:00:25 PM EDT

[#11]

I think I am going to go down the ultra short 300 blkout rabbit hole. I have a 10.5" sbr in 300 blkout already. Thinking about doing a 5" upper or maybe another sbr build.

My question is with your early testing. Are you finding a sweet spot as far as buffers? I plan to shoot suppressed and probably all subsonic. Definitely an adjustable gas block. What buffer weight would be a good start on these ultra short barrels?

Posted: 8/5/2018 7:11:39 PM EDT

[#12]

@vbpylot So far with the v7 6.5” and r2b 6”, as well as one other v7 6.5 I owned a while back, I have only used the standard buffer. I brought h2 and h3’s to the range but didn’t need them. Didn’t run more than a couple rounds suppressed, that will be later, wanted a good keyhole check first.

As for where to start: I just start with whatever I have on hand and go from there. Often enough, the first one I try works just fine

Posted: 8/5/2018 7:27:34 PM EDT

[#13]

Standard makes sense. Alot of gas from a suppressor to begin with. Definitely watching your testing. Curious what your suppressed results are. Thanks for doing this and thanks for the response.

Posted: 8/5/2018 10:46:26 PM EDT

[#14]

KAC recommends changing some of the buffer weights to aluminum , with there 6.25" barrel to cycle subs without a suppressor. Mine is a little under gassed and short strokes with Nosler 110 Varmagedon so I am going to lighten the buffer some. It ran fine with Fiochii 150gr FMJ supers.

Posted: 8/8/2018 8:40:56 PM EDT

[#15]

Quote History

Quoted:
KAC recommends changing some of the buffer weights to aluminum , with there 6.25" barrel to cycle subs without a suppressor. Mine is a little under gassed and short strokes with Nosler 110 Varmagedon so I am going to lighten the buffer some. It ran fine with Fiochii 150gr FMJ supers.

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kac has a 6.25" barrel?

Posted: 8/9/2018 8:21:49 AM EDT

[#16]

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kac has a 6.25" barrel?

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Think he meant KAK

https://www.kakindustry.com/ar-15-parts/upper-parts/barrels/300-blk/6-25-inch/kak-300-blackout-625-inch-pistol-stainless-barrel-5r7

Posted: 8/9/2018 5:20:49 PM EDT

[#17]

Veritas/SLR upper shipping today/tomorrow

Posted: 8/13/2018 6:37:49 PM EDT

[#18]

Article Part 1 is live

https://loadoutroom.com/50929/ultra-short-300-blackout-barrels-round-up-part-1/

Posted: 8/14/2018 1:44:26 AM EDT

[#19]

Pic request....

I’ve been eyeballing the Vseven 5.7” rail, but there doesn’t seem to be too many out in the wild. Can you post a few more pics of it on the gun? Bonus points for pics with suppressor mounted.

Posted: 8/14/2018 2:47:17 PM EDT

[#20]

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Pic request....

I’ve been eyeballing the Vseven 5.7” rail, but there doesn’t seem to be too many out in the wild. Can you post a few more pics of it on the gun? Bonus points for pics with suppressor mounted.

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The main photo in the article posted above has that rail with V7's 6.5", I'll see if I can figure out pic posting here, otherwise I'll put some on my IG account @Rexnanorum

Posted: 8/14/2018 2:56:32 PM EDT

[#21]

Posted: 8/14/2018 3:13:47 PM EDT

[#22]

I'll go snap a couple more today If I get a few minutes in the shop

Posted: 8/14/2018 4:41:54 PM EDT

[#23]

Posted: 8/14/2018 5:27:19 PM EDT

[#24]

Exactly what I was looking for. Thanks!

Posted: 8/15/2018 4:15:07 PM EDT

[#25]

KAK 6.25" and 4.75" both coming in. Need more ammo! work stash and personal stash both getting low

Posted: 8/18/2018 6:41:50 PM EDT

[#26]

I’m interested in the 4.75” from Kac

Posted: 8/20/2018 7:32:00 AM EDT

[#27]

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Quoted:
I’m interested in the 4.75” from Kac

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KAK...

Posted: 8/20/2018 9:08:16 PM EDT

[#28]

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Quoted:
I’m interested in the 4.75” from Kac

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Me too. That can’t possibly work...can it?

Posted: 8/20/2018 9:44:08 PM EDT

[#29]

they posted this on their instagram the other day, some guy testing one for them

https://www.youtube.com/watch?v=l35sPOQAYGg

Posted: 8/21/2018 3:46:49 PM EDT

[#30]

Two barrels from KAK are in, doing some dremel ninja work with extra ALG handguards I had around. Ammo from Ammo inc is in, some Federal subs incoming and a couple boxes of Discreet Ballistics.

Posted: 8/21/2018 11:30:14 PM EDT

[#31]

Seriously interested in that 4.75" from KAK. I've got a deep stash of 110gr Barnes blacktips and are dying to see what velocities you will get from the ultra shortie

Posted: 8/28/2018 7:30:10 PM EDT

[#32]

What size gas port are they using in the 6 inch size barrels, specifically that KAK 6.5 inch barrel?

Posted: 8/28/2018 7:53:55 PM EDT

[#33]

Quote History

Quoted:
Seriously interested in that 4.75" from KAK. I've got a deep stash of 110gr Barnes blacktips and are dying to see what velocities you will get from the ultra shortie

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This is of interest to me as well

Posted: 8/28/2018 10:34:07 PM EDT

[#34]

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Quoted:
What size gas port are they using in the 6 inch size barrels, specifically that KAK 6.5 inch barrel?

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.~~105~~ for the KAK 6.25 AND the 4.75", but the 4.75"'s gas post is closer in by 1.5"

edit for correction, .125

Posted: 8/28/2018 10:40:59 PM EDT

[#35]

Quote History

Quoted:
This is of interest to me as well

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Quoted:

Quoted:
Seriously interested in that 4.75" from KAK. I've got a deep stash of 110gr Barnes blacktips and are dying to see what velocities you will get from the ultra shortie

This is of interest to me as well

Article is coming...range day complete. A little teaser..

4.75 with barnes 110, around 1850 fps
6.25 with barnes 110, around 1950 fps

Posted: 8/29/2018 9:47:04 AM EDT

[#36]

I get 2000 FPS with 19.0 of Lil Gun behind the 110 Tac-Tx out of a 8.5”... what loads are you shooting?

Posted: 8/29/2018 9:51:48 AM EDT

[#37]

Quote History

Quoted:
Two barrels from KAK are in, doing some dremel ninja work with extra ALG handguards I had around. Ammo from Ammo inc is in, some Federal subs incoming and a couple boxes of Discreet Ballistics.

https://i.imgur.com/vRXm5M7h.jpg
https://i.imgur.com/S95esxSh.jpg
https://i.imgur.com/Dmw01fth.jpg
https://i.imgur.com/BVGinZ4h.jpg

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You did that with a dremel? It doesn’t look bad at all! Nice job.

Posted: 8/29/2018 11:41:49 AM EDT

[#38]

Quote History

Quoted:
I get 2000 FPS with 19.0 of Lil Gun behind the 110 Tac-Tx out of a 8.5”... what loads are you shooting?

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All testing was with factory ammo

Posted: 8/29/2018 1:20:41 PM EDT

[#39]

that's impressive!

Posted: 8/29/2018 1:37:11 PM EDT

[#40]

Quote History

Quoted:
.105 for the KAK 6.25 AND the 4.75", but the 4.75"'s gas post is closer in by 1.5"

View Quote View All Quotes

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Quote History

Quoted:

Quoted:
What size gas port are they using in the 6 inch size barrels, specifically that KAK 6.5 inch barrel?

.105 for the KAK 6.25 AND the 4.75", but the 4.75"'s gas post is closer in by 1.5"

Thank you.

Posted: 8/29/2018 1:40:19 PM EDT

[#41]

Quote History

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Thank you.

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@Big-Bore

.125. I just edited it for correction, my old calipers got too old, manufacturer let me know the correction, got my new calipers in as well.

Posted: 8/30/2018 3:37:35 PM EDT

[#42]

Thanks again. I really appreciate it. I'm trying to decide whether to do another .30 HRT but in a 6.5 inch or do a .300 BO in 6.5 inch. No subs are in the plans and it will be a purely kicks and giggles build. Since I already have a couple of .30 HRTs, it would be interesting to try a short one and it would not cost me a new set of dies, but the BO is better suited to long and heavy bullets while the HRT is a lot better suited to short and fast bullets. Decisions, decisions, decisions...

Posted: 9/3/2018 3:48:25 PM EDT

[#43]

Article part 2 done, will be submitted for editing and publishing soon.

For those of you with more experience than me in the area of shooting groups, I have a question:

If a barrel is shooting reasonably well (2-4 MOA, somewhat fast groups), then fires out a 14 MOA group.. whats the likely cause? Wasn't shooter error in this case.

4.75" KAK .300 blackout barrel, 1x7 twist, 120 gr Federal All Copper rounds, 50 yards, 4x ACOG

Posted: 9/3/2018 5:12:27 PM EDT

[#44]

That’s quite a change. First word to come to mind is loose. Loose scope, loose mount, loose barrel nut, loose gas block, loose muzzle device, muzzle device strike... Check everything. Next would be clean. Has the barrel been cleaned down to base metal using copper remover?

Posted: 9/3/2018 6:12:25 PM EDT

[#45]

Quote History

Quoted:
That’s quite a change. First word to come to mind is loose. Loose scope, loose mount, loose barrel nut, loose gas block, loose muzzle device, muzzle device strike... Check everything. Next would be clean. Has the barrel been cleaned down to base metal using copper remover?

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Checked all hardware in the field, nothing moved that shouldnt. Hadn't cleaned the barrel yet, was in the middle of a long range day and the next handful of groups went back to normal. Will scrub out before next range day and repeat

Posted: 9/3/2018 9:14:05 PM EDT

[#46]

Were these all with the same load? If they were all with the same load, getting good groups, then a bad group, then good groups again, I’d suspect the ammo in that case. Loose parts and heavily fouled barrels don’t just correct themselves mid shooting session. If that lone bad group was a separate load, then it could simply be a combo the barrel doesn’t like.

Posted: 9/6/2018 5:48:58 PM EDT

[#47]

Second article up.
Have a tracking number for Vertias Tactical/SLR upper with 5" barrel
Modern Outfitters MC6-SD seems to have fallen off their "to-do" list
None others pending

https://loadoutroom.com/51926/ultra-short-300-blackout-barrels-round-up-part-2/