SBR project

Howard Law
Mac11FA

Mac11FA

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Well, I sold my 300 BLKOUT upper this past weekend and am thinking of building a 300 BLKOUT SBR. Guess I will start from scratch and attempt the Form 1 myself. I am gonna have to hustle so I can get it done before the July 1. I am on the fence on barrel length/twist as I want to hunt suppressed and also use for HD. I also like the look of the hand guard hiding the suppressor. What are your thoughts?
 
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freedom

freedom

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I think anything longer than 9" does nothing ballistics wise for 300 subs.

I believe 1/8 has become the normal twist rate, but some companies still offer different ones.

I like the look of the hand guard covering the end, but only if it's never fired unsuppressed.
 
boss_hawg

boss_hawg

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I have a 300 sbr and here are some of my takeaways and observations.

I didn't hide the suppressor under the hand guard. my can is a sico SpecWar 762 which has a collar that needs to be turned to secure. so, unless there was a gap in the the rail/hand guard, I wouldn't be able to secure the can to the barrel. also, suppressors get hot and I don't want to be forced to use an oven mit when I shoot.

there have been a lot of studies to determine ideal barrel length for 300. current thinking is 9 to 10.5". I believe that Daniel defense, noveske, and advanced armament are all running either 9" or 10.3" as their standard shortest barrel. this is from memory so I may be mistaken. I went with an 8" or 8.5" cmmg barrel because it was steal. I haven't taken any mid-sized game with it yet, though.

I haven't and probably won't hunt with subsonic rounds. I don't think they are as effective at killing deer quickly and humanely. all bets are off for feral hogs, though.

I can't remember the twist rate of my barrel. I think it's 1x8 but who knows? it seems to shoot a wide range of ammo effectively with decent accuracy. I'll probably never shoot this beyond 200 yards with any ammo - sub or super - so sub moa was never my intent.
 
boss_hawg

boss_hawg

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ok, I went and checked it...my cmmg is 1x7.

here are some pictures because ever thread needs pics.

b2d1e2ab5cbd2a5f73c10a6d89c5c51b.jpg


7b449d053fdc724d290230f83a6e7240.jpg
 
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freedom

freedom

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boss_hawg said:
I have a 300 sbr and here are some of my takeaways and observations.

I didn't hide the suppressor under the hand guard. my can is a sico SpecWar 762 which has a collar that needs to be turned to secure. so, unless there was a gap in the the rail/hand guard, I wouldn't be able to secure the can to the barrel. also, suppressors get hot and I don't want to be forced to use an oven mit when I shoot.

there have been a lot of studies to determine ideal barrel length for 300. current thinking is 9 to 10.5". I believe that Daniel defense, noveske, and advanced armament are all running either 9" or 10.3" as their standard shortest barrel. this is from memory so I may be mistaken. I went with an 8" or 8.5" cmmg barrel because it was steal. I haven't taken any mid-sized game with it yet, though.

I haven't and probably won't hunt with subsonic rounds. I don't think they are as effective at killing deer quickly and humanely. all bets are off for feral hogs, though.

I can't remember the twist rate of my barrel. I think it's 1x8 but who knows? it seems to shoot a wide range of ammo effectively with decent accuracy. I'll probably never shoot this beyond 200 yards with any ammo - sub or super - so sub moa was never my intent.
Click to expand...

They are supposed to have devolved so bullets that reliably expand at subsonic speeds for 300aac. They are expensive, but I think they're out there now.
 
boss_hawg

boss_hawg

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freedom said:
They are supposed to have devolved so bullets that reliably expand at subsonic speeds for 300aac. They are expensive, but I think they're out there now.
Click to expand...
but, in my internet research, for what that's worth, a subsonic 300 bullet that expands into petals works more like a broad tip arrow. if I'm hunting with a firearm, I want the round to cause massive tissue damage due to hydrostatic shock and drop my future meal in its tracks.

not saying that subs won't get the job done but I try to take game as humanely as possible. if that means I have to wear ear pro because of a super sonic crack then it's a sacrifice I'm willing to make.

I guess it's a personal preference thing.
 
Cudruln

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I am running a 9.5" on my 300 blk. Shot it for the first time this past weekend (obviously suppressed) and it was a blast. From what I have found on my research is anything over 10.5" is not doing anything for you. Are you looking to build a upper or you just going to buy complete?
 
Willy Leadwell

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Mac11FA said:
Well, I sold my 300 BLKOUT upper this past weekend and am thinking of building a 300 BLKOUT SBR. Guess I will start from scratch and attempt the Form 1 myself. I am gonna have to hustle so I can get it done before the July 1. I am on the fence on barrel length/twist as I want to hunt suppressed and also use for HD. I also like the look of the hand guard hiding the suppressor. What are your thoughts?
Click to expand...
I would go ahead and form 1 the lower now while you decide what you want in an upper.
 
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Mac11FA

Mac11FA

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Cudruln said:
I am running a 9.5" on my 300 blk. Shot it for the first time this past weekend (obviously suppressed) and it was a blast. From what I have found on my research is anything over 10.5" is not doing anything for you. Are you looking to build a upper or you just going to buy complete?
Click to expand...
I have not decided yet. I wouldn't mind building from scratch although if I could find a good deal on a complate upper, I may go that route. I was looking to go between 8.5 and 10.5 on the length and the shorter the better. I am thinking of a SBR varmint rifle.
 
Cudruln

Cudruln

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Hardened arms or radical firearms (pretty sure they sell 300 blk) has some pretty sweet deals on complete uppers. May be worth looking into.
 
Wiskey_33

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I agree on keeping it short. My brother has a 16" 300 BO upper and even the subs in that barrel length are right at the limit. Some do go super. UMC sub ammo is a lot more consistent than the Federal AE Sub ammo.
 
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DevilDoc602

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