I've played with a smaller cartridge in .308 for years and have thought about doing the 300 BLK since it looks like a nice intermediate cartridge that uses easy to find brass. My problem is I've been shooting bullets mostly in the 110gr to 155gr range supersonic and wondered about the standard 1:8 twist rate used in the 300 BLK. Do you think that maybe sometime down the road the manufacturers might offer twist rates that might work better for those that want supersonic rounds only or do I need to just go to a gunsmith and have a custom barrel made.

7.62 x 40 might be a better choice at that point.  You'll get better velocity and you could buy a barrel off the shelf from Wilson.

There's a thread around here someplace that describes it.  Or the Wilson Combat website.

+1 on the 7.62X40. That round was designed for supersonic use of a .30cal bullet out of a AR15. The 300 was designed for subsonic use, hence the 1:7 twist rate. If you plan to shoot supersonic, there are better choices than the 300.

Wrong again the 300BLK was designed for supersonic with the capabilities of going subsonic. Wrong on the twist rates too as most have 1:8 twist rates that have had no problems in accuracy.

The 300BLK is capable of sub MOA at 1:8 twist rates shooting supersonics in the 110-150gr range. As a matter of fact all of the supersonic production ammo made for the blackout fall within the weight range the OP was looking at.

Funny those pimping the 7.62 X 40 are people who shoot the 6.8WTF and don't want another person buying the 300BLK to compete with their cartridge. Knowing full well the 7.62 X 40 is no competition because it only has one manufacture, the ammo is more expensive than the 300BLK, there is only one company that makes ammo for it, very limited selection in said ammo compared to the 300BLK, brass is more expensive, REQUIRES MODIFIED MAGS and cannot shoot subsonic.

All of these disadvantages for the small gain of 85fps which is less than I reduce my loads to get more uses out of my brass.

The 300BLK has major industry support, has multiple major manufactures for the ammo, is SAAMI approved round so anyone can make barrels, uppers, ammo for it and have the same specs. Here is a list of manufacture of 300BLK stuff:


AAC - uppers, rifles, silencers, and ammunition.
* Adams Arms - rifles and uppers.
* Addax Tactical
* Alexander Arms - rifles.
* All Weather Arms - brass processing.
* Ambush Firearms - rifles.
* Arnold's Ammo - ammo.
* AR-Stoner - barrels.
* Atlanta Arms - ammo.
* AR-X Enterprises - barrels, uppers, rifles.
* Barnes Bullets - ammo, bullets.
* Barnes Precision Machine - barrels, uppers.
* BFG Cartridges - Savage barrels.
* Black Hills Ammunition - ammo.
* Black Hole Weaponry - barrels.
* Brad's Warehouse - converted brass.
* Bushmaster Firearms - uppers and rifles.
* BWE Firearms - rifles, uppers, and suppressors.
* Chattahoochee Gun Works - uppers, rifles.
* CMMG - barrels, uppers, and ammo.
* Compass Lake Engineering - AR barrels.
* Cor-Bon - ammo
* Core15 - rifles, uppers.
* Custom Reloads of Dallas - ammo.
* Daniel Defense - rifles.
* Delta Company Arms - rifles, barrels, uppers.
* Dillon Precision - reloading conversion kits.
* Double Tap - ammo.
* DPMS - rifles and uppers.
* DS Arms - rifles and uppers.
* ER Shaw - barrels.
* Forster - reloading dies.
* Grim Reaper Tactical - barrels, uppers, lowers, and rifles.
* Gunn - ammo.
* Hornady - ammo, dies, brass.
* Houston Armory - barrels.
* Kel-Tec - SU16C.
* Kiss Tactical - lowers.
* Lee - reloading dies.
* Lehigh Defense - bullets, ammo.
* L.E. Wilson - case gauges.
* Lewis Machine and Tool - barrels, uppers, rifles.
* Loki Weapon Systems - uppers/rifles.
* Lone Star Armory - 300 AAC BLACKOUT marked lowers.
* Lothar Walther - barrels.
* LWRCI - rifles.
* Match Grade Machine - Thompson barrels.
* McGowen Barrel - Savage and other barrels.
* McCourt Munitions - ammo.
* Model 1 Sales - AR barrels/uppers
* Montana Rifleman - barrels.
* Noveske - rifles and uppers.
* Olympic Arms - rifles and uppers.
* One Shot - ammo.
* Pac-Nor - barrels.
* Outlaw State Bullets - bullets.
* Pacific Tool and Gauge - reamers and gauges.
* PalmettoStateArmory - uppers, barrels.
* PNW Arms - ammo.
* Primary Weapons Systems - rifles and uppers.
* Profire Arms & Supply - ammo.
* Rainier Arms - barrels.
* Raven Armament Company - ammo and uppers.
* RCBS - dies.
* Red Star Ammunition.
* Redding - dies.
* Remington - ammunition.
* Right 2 Bear Ammo - ammunition.
* River Valley Ordnance - reformed brass.
* Robarms - XCR Micro rifle.
* RMW / Ron Williams - barrels.
* RUAG - ammo.
* Satern Custom Machining, Inc. - barrels.
* Savage - rifles.
* Seekins Precision - rifles.
* Selph Arms LLC - barrels, uppers, re-chambering, and rifles.
* Sheepdog Ammo - ammo.
* SI Defense - barrels.
* Sig Sauer - rifles.
* Silver State Armory - brass, ammo.
* Smith & Wesson - rifles, uppers.
* SNIPERCO - uppers.
* Sierra - bullets.
* SilencerCo - silencers.
* Sota Arms - barrels.
* Southern Ballistic Research - ammo.
* Southwest Ammunition, LLC - ammo.
* Spike's Tactical - uppers and rifles.
* Summit - ammo.
* Surefire - 300 BLK sound suppressor.
* Tactical Machining - lowers.
* The Bullet Works - bullets and ammunition.
* Top Notch Tactical - ammo.
* Triton Arms - AR barrels.
* Ultra Tech - ammo (Australia)
* Umlaut Industries - 300 BLK caliber marked Rifles, Upper and Lowers. 16" and 10" Factory Title II.
* Underground Tactical Arms - uppers.
* White Oak Precision - AR barrels.
* Whidden Gunworks - trim dies.
* Wilson Combat - rifles, hunting and self defense ammunition.


Now compare that to who makes stuff for the 7.62 X 40:

Wilson Combat.

OP, 1 in 8 and the supposedly forthcoming 1 in 7 twist barrels will be just fine for supers.  I have yet to see a reliable, peer reviewed scientific paper that says you can get too much twist rate on any bullets besides 22 and lower caliber varmint bullets going 3000+ fps.

Robert Silvers (I know, anathema on this site) tested the BLK down to 1 in 4.5 and a 6" barrel or something crazy and it was just fine.  300 BLK bullets won't explode upon exiting the barrel from "over stabilization."

Has it ever been proven via the scientific method that slower twist gives higher velocities or better accuracy?

And before anyone goes off on me for wanting to see an official study, please know that I am just like this with "global warming/climate change."  Screaming from liberals climate scientists who do bad science has made me very skeptical of every single "claim" people like to make.

I am skeptical of everything and everyone.  (Especially folks who shoot the 6.8.  )

The 300 was not designed for supersonic use, hence its sub par supersonic performance and the 1:7 or "1:8" twist. Those twist rates are to stablize heavy .30 cal bullets, for subs. That is where the mortar effect comes into play.

And I don't give a shit who buys what, if you want to shoot a round with less power than a AK but costs twice as much, gourd head, your money. The 300 is a niche round for short barrels, suppressors and subs, no more and no less.

You can remove Savage from that list also.

I do not have "sub par performance" out of my 1:8 twist 300 AAC.  I shoot supersonic, and I might add it is very accurate!
Try it...once you go black you won't go back!!

Edit to add....this was my 300th post!! fitting subject!

I've been shooting bullets from 110gr Barnes TSX's to the Sierra 155gr Palma Match through a 1:10 barrel with very good accuracy. I was just a bit surprised that the 1:8 twist in the 300 Blk was doing well. For those that want to poop on the power of the round I do shoot 7.62X39 and find it more that adequate for my needs. The 300 BLK is only a little less powerful and that wouldn't be a big deal for me –– I just wanted something that used more standardized AR parts. If I really need to use more power I have a .308.

I went with 300blk also.  I was just saying that if you were going to go to the trouble of a custom barrel for supers that you might just as well go with the x40.  So far as I know 300blk is the only thing going that has both parts commonality and industry support.  It certainly does create a lot of drama in this forum either way as I'm sure you've noticed.    



If that's me you mean I'm certainly not.  I have a 300blk.  I have neither a x40 nor a 6.8.  My point was very simply that if someone was going to go to the trouble to have a 300blk barrel custom made with a lower twist rate that they might be better off with a cartridge somewhat more optimized for shooting supers.  The reasoning was that I assumed that if someone buys a custom barrel they probably are looking for performance over industry support.

My response wasn't for you it was for the troll 346ci who comes on every 300BLK thread and either tells the OP to get a 6.8 or how the 300BLK doesn't have enough power to shoot a squirrel out of a tree even though nobody asked him.

I took the meaning a different way in he was asking for a slower twist and it has been proven over and over that the slower twist is not needed for more accuracy out of the 300BLK.

Yes, there are some companies doing 1x11" twist for light bullet only usage: http://www.blackholeweaponry.com/catalog/index.php?cPath=61

Edited...VA-gunnut
 

Sinnerman,
    Thanks for the very nice and "To the Point" reply. I'm not sure why the moderators allow all this BS and I for one am tired of it. This isn't a discussion forum but an information forum and I asked a pretty straight forward question about a specific item. Needless to say there is no reason for me paying membership dues next year.

    I'd ask about bullet lenghts that could be used in the 7.62X40 and what were the standard twist rates but I'd almost bet I'd have to go through another pile of BS before I got a decent answer. I think the shorter 300 BLK cartridge would work best for me.

I did have a bit of a problem with trying to go with a non-standard barrel twist –– more knowledgeable people put a lot of testing into that and I've only worked with the 1:10 twist. The other point was that by some chance I might actually want to try subsonic in the future –– not likely but who knows. I like to load my own ammo and would look forward to working with this round.

What would the weight be on one of your units with the fluted barrel? I like to keep things as light as possible.

Edited...VA-gunnut


 

Edited...VA-gunnut










On track, I had a 16" barrel and was mostly shooting 150's out of it. Great accuracy, and very effective on deer, pigs, and coyotes. I now have an 8" barrel and it has so far been accurate with 150's - 208's all are handloads. I havent had the time to try and really try for 100 yard groups but at 50 its 5 rounds in one ragged hole. All of the shooting ive been doing has been with my aac 7.62sd on.
 

I've got all 3, 7.62x40WT, .300 Blackout and 6.8, as well as two Grendels and a .264 LBC...and of course a bunch of other calibers...

my thoughts:
7.62x40WT, easy to make brass from 5.56 surplus brass, decent cartridge for medium sized game to medium distance, good bullet selection, especially the Barnes TTSX that is made for it for expanding at lower velocities than the standard .308 round

300 BLK, good cartride, easy to make brass from 5.56 surplus brass, with most of the barrels at 1:8 twist with some probably going to 1:7 twist, the ideal setup for it is heavier bullets, subsonic, suppressed, however you can shoot lighter bullets at this twist rate with reasonable accuraccy, not as long a range gun as the 7.62x40WT

6.8, brass is more expensive, but good supply and makers, longer range than either the 7.62x40WT or 300 BLK, ideally for supersonic rounds, however Bison now makes the 6.8 BSP also, with matching 200gr Woodleight bullets for subsonic suppressed, which I also have one of....

So its really a call on what you plan to use it for?  I like all 3 cartridges, I own 3 300 BLK, two 7.62x40WT, and 4 6.8's, and one 6.8 BSP....All good guns, not one good at everything, but possibly depending on the distance you want to shoot, if you plan on subsonic and supersonice, then either the 300 BLK or 6.8 BSP, both will cycle either subsonic and supersonice, suppressed or unsuppressed

just my thoughts, i'm not a promoter of any of them, I have my feelings about each, but I own all of them for a reason, different purposes applied to hunting applications, since I can own each, I do and don't make any of them my 'go-to' gun, however each one is my 'go-to' gun for a certain purposes, whether hunting antelope, deer, hogs or whatever, day hunting, night hunting, etc...

so, I have them all, and like them all

Well said Elkbow, with facts and no over hyped BS. I'm trying to talk myself into a .264 now, if I only had the range to stretch it out there would be no question.

Thanks guys –– I really appreciate the input on the twist rate.

Lets not try to start another pissing match. I got the information I needed and I'm starting to collect parts.

Um,.... The original name is the 300 Whisper (designed by JD Jones of SSK Industries). In addition, AAC is known for making silencers. Kinda give a hint of the answer.

Other than that. I'm staying out of this. The OP got his info.

yea here in New Mexico we have wide open spaces, and great long range hunting for antelope, mule deer, barbary sheep, etc., and the rifle range I belong to goes out to 760 yards, which is nice, and if you want to do 1000 yards or more, then we just go out to the open prairies....going way out there though I use my 6.5 Creedmoor  you should head out this way for some hunting....

Thanks, I'd love to come out and sling some lead. Its tough for me to take a few weeks off during November/December for our deer season though, much less travel out of state to hunt. Work keeps me rolling but that is a good thing.

yea copy that...darn work lol, our Antelope season is now in August, so antelope are in the rut, so works out good, just hard to draw, i've taken 3 record book antelope with the bow, this will be the first year i've put in with rifle due to health issues

Thanks for this information. With the legalization of suppressors for hunting in Texas I am interested in this round for a rifle for my son. He is a young shooter and I don't want his hearing to end up like daddy's.