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View Full Version : 300 BO in a long(ish) barrel Single Shot?



greywuuf
03-15-2022, 08:27 PM
Considering as an option to build ( I have a 1:8 blank and the group buy 247 grain boolit) and I was thinking in a long barrel (21-24" ish) it might be mouse fart quiet fun for small game and usable on slightly bigger stuff? ....any one played with the BO in a single shot? What kind of results and thoughts ?

John McCorkle
03-15-2022, 11:24 PM
Have one in a bolt action 16 inch barrel and love it. I can't imagine a single shot would be any quieter since neither action has moving parts during the firing cycle though I bet a single shot would be a heck of a lot of fun.

Muzzle pressure curves (as modeled in software) really gets low after 16 or 18 inches but has a slow diminishing decline....but a long barrel would be a dream in a heavy bullet subsonic load...even without a can.

That 1:8 may have trouble stabilizing that long of a bullet though...longer barrel length may help but you'd just have to try it and see.

My go to mousefart in 300 blk is a 90 grain sec from Lee over about 3.5 grains of titegroup ...out of that long barrel it would be pure giggles and smiles

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greywuuf
03-16-2022, 12:40 AM
Have one in a bolt action 16 inch barrel and love it. I can't imagine a single shot would be any quieter since neither action has moving parts during the firing cycle though I bet a single shot would be a heck of a lot of fun.



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i forget people built things other than AR's in Blackout. I was just thinking with such a small case that my bore Volume would increase pretty rapidly with the longer barrel and i might end up with a cheap fun and quiet small game gun... with a lot of luck I was hoping to push it up to larger game once a year ( either with a long bullet that tumbled on impact as people have reported works well through a can for culling deer, or with a more conventional bullet driven faster ...) seems that 1:8 is a horrible choice as I am told it is too fast for cast bullets and to slow for good long subsonic...... though I bought this blank before i retired ( the same year the BO was released) and 1:8 was about as fast as i could find at the time.

mvozz
03-16-2022, 12:04 PM
I just started playing with a 300 BO Handi Rifle. Twist is 1:7 and it loves 135 gr cast with 4.5 gr of Trail Boss!! Watch Full Lead Taco on Youtube for his review of his single shot 300 BO and his Bunny Fart loads. He had NOE design (or modify) one just for that purpose, awesome. That video is what got me to buy one! They are so fun that my buddy tried them and bought a CVA single shot. Right now I am playing with 220 gr Berry's bullets and Lil Gun, if I like them enough I will be looking for another mould!

popper
03-16-2022, 03:01 PM
I have a SS 16" 1:8 CVA, lots of fun with 170gr, heaviest I've gone. Longer barrel won't help much. I get 1200 fps with cfe pistol or 2400, low recoil. Even with pistol powder the muzzle gas fps is 1600 or so. Bullet actually slows down in the longer barrel. Use the same load in 10" AR pistol, not too loud. Outdoors you probable could get by without muffs for a shot. I use a 145gr GC for hot loads in both as a pig load, 2k fps. Scope set for 50 yds.
297720

fixit
03-17-2022, 02:47 PM
With a longer barrel, I would think you could work with some slower powder's to get higher velocities if wanted... and would probably open the door for other powders for the moose farts,too.

John McCorkle
03-17-2022, 05:46 PM
Yes I've been fascinated with the idea of a long long barrel in 300 blk for a while. Loads of internet ballisticians will say it isn't much good after 10 inches of barely but....357 mag/357 max have similar case volumes....30 herret has similar case volume....all can and are found in 20+ inch barrels often. Depending on load and powder you'd see an appreciable velocity bump that makes sense.

300 blk as a supersonic round makes alot of sense. I've taken deer with it often and it works well. And muzzle blast is very mild.... without a can. Not hearing safe but nothing close to other calibers concussion or blast/volume. May not amount to much but I prefer to hunt with as low concussion as I can for multiple reasons...my hearing being a big one. May not be hearing safe but the damage done by a 300 blk and a 7mm mag are worlds apart.

I'd like to see what that little case would do out of a 22-24 inch barrel with a slower power...you'd have to find one that has a high energy density and med fast to medium burn...maybe a 125-140 grain bullet.

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Daekar
03-17-2022, 06:51 PM
Yes I've been fascinated with the idea of a long long barrel in 300 blk for a while. Loads of internet ballisticians will say it isn't much good after 10 inches of barely but....357 mag/357 max have similar case volumes....30 herret has similar case volume....all can and are found in 20+ inch barrels often. Depending on load and powder you'd see an appreciable velocity bump that makes sense.

300 blk as a supersonic round makes alot of sense. I've taken deer with it often and it works well. And muzzle blast is very mild.... without a can. Not hearing safe but nothing close to other calibers concussion or blast/volume. May not amount to much but I prefer to hunt with as low concussion as I can for multiple reasons...my hearing being a big one. May not be hearing safe but the damage done by a 300 blk and a 7mm mag are worlds apart.

I'd like to see what that little case would do out of a 22-24 inch barrel with a slower power...you'd have to find one that has a high energy density and med fast to medium burn...maybe a 125-140 grain bullet.

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Lil'Gun works well in 357mag rifles and can push impressive velocities. Might work in 300bo... although it likes heavy bullets.

John McCorkle
03-17-2022, 07:36 PM
Lil'Gun works well in 357mag rifles and can push impressive velocities. Might work in 300bo... although it likes heavy bullets.Playing with 1680 in quick load gives some interesting results in long barrels too....now granted that is pure software model and real results are likely to differ but I don't think it will differ so much that it's completely off base

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greywuuf
03-19-2022, 09:01 PM
I may just give it a go. Having lots of issues with a smokeless mil surp rolling block I have.....it is a carbine at only 21" but a very handy little rifle. I have this 1:8 blank sitting here, and I have a ton of brass and small rifle primers....might be an I teresting project.

chubcobear
03-22-2022, 08:20 AM
I shoot a Rem 700 Blackout with a 16" barrel for subsonic and I'm trying to find some subsonic date for lead bullets, specifically a 185 grain by Matts Bullets in Arkansas. Kinda need some help. Never shot lead before in this gun.

Moderator, if this is the wrong place, please move me to the right one.

John McCorkle
03-22-2022, 09:42 AM
I may just give it a go. Having lots of issues with a smokeless mil surp rolling block I have.....it is a carbine at only 21" but a very handy little rifle. I have this 1:8 blank sitting here, and I have a ton of brass and small rifle primers....might be an I teresting project.I think you'd have the only rolling block 300 blk in the world....which is super cool

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ulav8r
03-23-2022, 12:35 AM
I shoot a Rem 700 Blackout with a 16" barrel for subsonic and I'm trying to find some subsonic date for lead bullets, specifically a 185 grain by Matts Bullets in Arkansas. Kinda need some help. Never shot lead before in this gun.

Moderator, if this is the wrong place, please move me to the right one.

Right sub forum, wrong thread. You will get a better response if you start your own thread. I can't help answer your question.

chubcobear
03-30-2022, 08:03 AM
Thanks. Arkansas, too. Bryant.

rockrat
03-30-2022, 07:34 PM
I had a 24" 300 B/O on a Remington bolt action. Ended up rechambering it to 30 Apache (223 full length). Liked it a lot better

reddog81
03-31-2022, 01:44 PM
I shoot a Rem 700 Blackout with a 16" barrel for subsonic and I'm trying to find some subsonic date for lead bullets, specifically a 185 grain by Matts Bullets in Arkansas. Kinda need some help. Never shot lead before in this gun.

Moderator, if this is the wrong place, please move me to the right one.

With a single shot or a bolt action your powder options are much greater than when using an AR. For my 185 to 200 grain bullets I use 5.5 grain Unique for a velocity right around 1050 FPS in a 16" Ruger American Ranch. VV N340 got similar results but it's a less common powder.

Nobade
03-31-2022, 04:20 PM
My CZ527 carbine in 7.62x39 is kind of similar. It has a 1:7 or so twist rate and will accurately shoot the NOE 250 at 950 fps with Trailboss. It's not particularly quiet, but low enough to not need ear plugs. And it hits pretty hard out to 200M on the steel. Another fun one is a TC Contender in 32 H&R mag with a .308" 1:10 barrel 21 inches long. It shoots 220gr quite well and doesn't have much choice about being subsonic, with that tiny case.