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300 Blackout Benchrest Rifle
MG1890
Member Posts: 4,649
I'm seriously thinking of throwing a 300 Blackout barrel on my .222 benchrest rifle, just for something new to play with.
Anybody have any experience with this cartridge in regards to its' inherent accuracy? My Deuce will shoot in the high .1's.... What will the Blackout do when subsonic? What bullet, what twist?? Pros & cons??
Anybody have any experience with this cartridge in regards to its' inherent accuracy? My Deuce will shoot in the high .1's.... What will the Blackout do when subsonic? What bullet, what twist?? Pros & cons??
Comments
I would go with a 1 in 7 twist, if you want to go heavy and subsonic. The bullet(s) of choice will be the Sierra 240 grain SMK, or the Berger 210 VLD.
As far as "high 0.1's", I might not expect that, unless you pay close attention to your case preparation, like you do with the Triple Deuce, to get those kind of groups. I suspect you were talking about those groups at 100 yards. I would expect 1/2 MOA or better, if the rifle is built right, and the ammo loaded right. If you have a 20mph cross wind, I would expect the 300 Blackout to be better than the Triple Deuce.
Best
EDIT 1
quote:If I wanted to build another benchrest rifle just to win I would build a 30AR.
Not so sure that is the chambering I would choose. If it was not on the PPC case, it would be on the Remington BR(Benchrest) case, using a short fat body, and small primer pocket. Most likely in the 6.5mm flavor.
Best
From what I have read, most score benchrest is shot with 130 grain .30 cals.
Why subsonic?
From what I have read, most score benchrest is shot with 130 grain .30 cals.
The 300 whisper was designed as shooting a long, heavy, bullet at just under subsonic speed with good accuracy. In theory, a SBR or pistol wtih suppressor. The big heavy bullets are still moving pretty good (long heavy bullets retain velocity better) moving at a respective pace "at distance". Yes, rainbow trajectory, but that is what laser range finders, etc. were made for. And because of the mass it still carries plenty of energy.
The 300 blackout is a standardized and commercialized version of the whisper wtih a name change due to patent/trademark/copyright issues.
According to J.D. Jones, the definition of a Whisper cartridge is one that can be loaded with heavy bullets subsonic and light bullets supersonic.
Of course the OP should try different combinations looking for benchrest accuracy.
I've run through about 300 rounds of ammo, the 125 to 130 grainers do best. I like the Sierra 125 BTHP MK with IMR 4227, H110 and Blue Dot.
Case neck tension seems to be pretty important, and a variable when using cut down 5.56 ammo - I can feel the difference when seating a bullet that has a thin neck. Buying "factory original" 300 AAC brass seems best.
There's quite a POI difference bewteen the 2,100 fps light stuff, the 1,600 or so 150 grain stuff and the subsonic stuff.
It seems like a neat little cartridge, fun out to about 100 yds. I think it has pretty good potential, maybe not 222 Remington potential but pretty good.
I have the Remington 700 in 300 AAC, 16" barrel with AAC brake in an HS stock. The short barrel is about .875 diameter at the muzzle - very stout. I use a 5.5 to 16.5 Monarch.
I've run through about 300 rounds of ammo, the 125 to 130 grainers do best. I like the Sierra 125 BTHP MK with IMR 4227, H110 and Blue Dot.
Case neck tension seems to be pretty important, and a variable when using cut down 5.56 ammo - I can feel the difference when seating a bullet that has a thin neck. Buying "factory original" 300 AAC brass seems best.
There's quite a POI difference bewteen the 2,100 fps light stuff, the 1,600 or so 150 grain stuff and the subsonic stuff.
It seems like a neat little cartridge, fun out to about 100 yds. I think it has pretty good potential, maybe not 222 Remington potential but pretty good.
So, what will it do accuracywise????
Why subsonic?? I don't know. Sounds like fun. If I wanted to build another benchrest rifle just to win I would build a 30AR. I don't want to change my boltface, I may pickup another complete bolt, but the Blackout subsonic just seems like a fun project. I may even smoke a deer with it.
quote:Originally posted by dfletcher
I have the Remington 700 in 300 AAC, 16" barrel with AAC brake in an HS stock. The short barrel is about .875 diameter at the muzzle - very stout. I use a 5.5 to 16.5 Monarch.
I've run through about 300 rounds of ammo, the 125 to 130 grainers do best. I like the Sierra 125 BTHP MK with IMR 4227, H110 and Blue Dot.
Case neck tension seems to be pretty important, and a variable when using cut down 5.56 ammo - I can feel the difference when seating a bullet that has a thin neck. Buying "factory original" 300 AAC brass seems best.
There's quite a POI difference bewteen the 2,100 fps light stuff, the 1,600 or so 150 grain stuff and the subsonic stuff.
It seems like a neat little cartridge, fun out to about 100 yds. I think it has pretty good potential, maybe not 222 Remington potential but pretty good.
So, what will it do accuracywise????
Why subsonic?? I don't know. Sounds like fun. If I wanted to build another benchrest rifle just to win I would build a 30AR. I don't want to change my boltface, I may pickup another complete bolt, but the Blackout subsonic just seems like a fun project. I may even smoke a deer with it.
It will do 5 shots at or just under 1" @ 100 yds so long as I pay attention. I think it could do better, but I bought it as a "lite 30 cal plinker" and because given the powder shortage I thought using less would be best. I use a Monarch 5.5 to 16.5X scope and the reticle is a bit on the thick side, makes aiming a bit more of a challenge.
I haven't fiddled around with the 175s, 180s and 200 grain bullets. There's a fellow out there who makes 22 caliber sabots for the Blackout. They're a bit different than the EA Brown type in thatthey can be used through a brake. An odd arrangement - taking a 22 caliber cartridge, cutting it down so a 30 caliber bullet can be used - then sticking a 22 caliber sabot into the cutdown case.