1sakonut Posted January 12, 2022 Report Share Posted January 12, 2022 Good Evening, Thinking about having a 300 Blackout built , not sure what barrel twist I need 1-7 or 1-8 , I what to shot it subsonic so maybe going to use heavy 200 grn Bullets , any advice from members using this calibre very welcomed. thanks in advance. steve. Quote Link to comment Share on other sites More sharing options...
1sakonut Posted January 12, 2022 Author Report Share Posted January 12, 2022 Sorry about the spelling mistake😀 Quote Link to comment Share on other sites More sharing options...
Andrew Posted January 13, 2022 Report Share Posted January 13, 2022 I have a few 300 AAC. (Ruger, CZ 527, AR 10" and a 20 " AR) I think they are all 1-7" and all shoot well. ~Andrew Quote Link to comment Share on other sites More sharing options...
1sakonut Posted January 15, 2022 Author Report Share Posted January 15, 2022 Thanks Andrew, that’s the barrel twist I was considering after doing a bit more research into calibre it seems the way to go, just wanted someone that uses a blackout to confirm that for me thanks for you help. Quote Link to comment Share on other sites More sharing options...
BlueBoy69 Posted January 17, 2022 Report Share Posted January 17, 2022 I have a suppressed (a Wildcat Evolution) Remington Model 700 SPS Tactical AAC-SD in 300 AAC Blackout, its 5R barrel has a twist rate of 1:7". I normally use 165 grain H&N round nose copper-plated, plastic coated bullets loaded to subsonic velocity for plinking, but they are hard to get now. When fired from the suppressed rifle they make 'very' little noise. The firing report is more akin to an air-rifle than a firearm. The main noise heard is the bullet's impact with the target. I have a few other bullets to develop loads for, these can be seen in the attached image. Left is an NOE '311-232-FN PB AZ1' 235 grain plain-based cast lead bullet. The middle is a custom 220 grain ball-tip subsonic expander produced by Pete Watson of MME for me. The right an NOE '311-232-FN GC AZ1' 236 grain gas-checked cast lead bullet. The two lead bullets were cast and sized (to 0.309") by me. When they finally arrive, I've also got a job lot of 240 grain Sierra Match Kings to develop a load for too. Quote Link to comment Share on other sites More sharing options...
banus02 Posted January 17, 2022 Report Share Posted January 17, 2022 sorry if off topic but could the mme bullet be used subsonic in a 308 win rifle? Quote Link to comment Share on other sites More sharing options...
BlueBoy69 Posted January 17, 2022 Report Share Posted January 17, 2022 1 hour ago, banus02 said: sorry if off topic but could the mme bullet be used subsonic in a 308 win rifle? As far as I know it's 308 cartridge agnostic, though I'd imagine some smaller cartridges (30 Carbine, etc.) would have a problem using it 😄 I guess it's all down to if your rifle has a fast enough twist rate? The MME 220 gr BT bullet is about 1.414" (35.92 mm) long. So at subsonic speeds (lets say 1,070 fps), to be gyroscopically stable it will need a twist rate of about 1:11". Obviously that's a very crude estimation, but probably not too far off. When I enquired about heavy-weight 308 BT bullets, Pete Watson stated in an email that he could make any weight up to 250'ish grains. Quote Link to comment Share on other sites More sharing options...
banus02 Posted January 17, 2022 Report Share Posted January 17, 2022 good evening blueboy 69, i have a ruger precision rifle with a 1 in 10 twist .so this should be ok ? Quote Link to comment Share on other sites More sharing options...
BlueBoy69 Posted January 17, 2022 Report Share Posted January 17, 2022 5 minutes ago, banus02 said: good evening blueboy 69, i have a ruger precision rifle with a 1 in 10 twist .so this should be ok ? It would seem likely that it would be stable. The specs for the MME 220 gr BT bullets are: Overall Length: ≈1.414 inches (≈35.92 mm) Plastic Tip Length: 0.057 inches (≈1.44 mm) Weight: ≈220 grains (14.26 grams) You can use those details to plug into the various online stability calculators to do your own calculations. I don't have any ballistic drag data for it, but when I test some loads, I'll use the Labradar to get this information. Quote Link to comment Share on other sites More sharing options...
banus02 Posted January 17, 2022 Report Share Posted January 17, 2022 thank you. Quote Link to comment Share on other sites More sharing options...
1sakonut Posted January 18, 2022 Author Report Share Posted January 18, 2022 Thanks BlueBoy 69 Quote Link to comment Share on other sites More sharing options...
Andrew Posted January 19, 2022 Report Share Posted January 19, 2022 On 1/15/2022 at 12:08 AM, 1sakonut said: Thanks Andrew, that’s the barrel twist I was considering after doing a bit more research into calibre it seems the way to go, just wanted someone that uses a blackout to confirm that for me thanks for you help. I wasn't 100% certain but I checked. That CZ is a 1:7 as well. You can't go too far wrong with that twist. ~Andrew Quote Link to comment Share on other sites More sharing options...
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