HD Tactical

Don't see load data for 10.5 inch barrels 300BO

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  • Rebel_Rider1969

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    My Hornady book only has loads for 16 inch (1:7.5 twist.) How do you convert the load data to match the 10.5 inch barrel? To get the same results.
     

    kendive

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    You better get you a chrono and maybe a few of them. I had three at one time down to two now. Go out and test your loads and get the results you want.

    You loading subs? I have a 10.5" barrel SBR 300 BO and only shoot subs out of it suppressed. I also played around with drilling out the gas port on the barrel to get the gun to cycle without the suppressor. You can make that work...

    Not sure what you mean get same results from a 16" barrel to a 10.5"??? Is that really achievable? There is only so much room for powder in a 300 BO Case.

    Maybe use rocket assist?

    Took me about a year to perfect two subsonic loads .308 for an 180gr and 220gr bullet with my rem 700. I use no books to get there just trial and error.

    Good luck.

    Here is some of my data for 300BO Subsonics.

    1098 ft/s 10gr 5744 220gr Black Power Coated
    1093 ft/s 10gr 5744 220gr Black Power Coated
    1097 ft/s 10gr 5744 220gr Black Power Coated
    1134 ft/s 10gr 5744 220gr Black Power Coated








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    Daezee

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    A short Blackout bbl will never be as fast as a 16” Blackout bbl using the same load data. Just use regular load data until you get the accuracy and velocity without high pressure signs that fits your needs.
     

    Rebel_Rider1969

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    Thanks. I'm just going to have to slow down. It's just strange to me that with so many short barrels out there nobody has put together a load book for short barrel weapons. Interested in Subs and supers.

    Gyrojet projectiles?(joke)
     
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    Baddog 0302

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    A general SWAG on Bbl. length to FPS is 50 FPS + or - to know data, so you are about 250 fps (+ -) slower that what H says for their 16" bbl.
    That being said, you are not going to get the muzzle Vel. out of a 10.5" bbl that even the lawyer/ law suit inspired load data says one can get form a 16" Bbl.
    With out way to check your MV HOW do you know what your little Bbl. is producing ??

    A 300 BO,300 Whisper, 300/221, are all the same and have , depending on the powder about .5 to .75 grains more powder capacity that the .30 Carbine, 30-20 {32-20} and the 30 Reece [.30/38 Spl.} .

    I may still have a load data sheet from the three cases above. IF I do I'll pm you.

    NOT trying to be a smart ass , but why would you invest $$$ in an AR upper in 300 BO and not have any load data other that what a book says ???
    Suggest you google load data for the three others and specify pistol data to match your 10.5" bbl.
     
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    Rebel_Rider1969

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    My limited knowledge, needs to be greatly improved on this. I did think of something I learned reading on the 45 colt. Crimps. Tighter makes more or in most cases too much pressure. I would never try it.
     

    Daezee

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    Thanks. I'm just going to have to slow down. It's just strange to me that with so many short barrels out there nobody has put together a load book for short barrel weapons. Interested in Subs and supers.

    Gyrojet projectiles?(joke)

    Sometimes folks assume that loading for a short bbl rifle caliber AR is way different than a longer bbl AR. After all, why not use a faster burning powder in order to consume more of it in the short bbl? Kinda makes sense. A factor that people can forget is that it takes a minimum amount of pressure/gas to function the AR action, no matter what the bbl length is. In other words, the AR action (buffer spring, buffer weight, BCG weigh, cam pin movement, bolt unlocking, gas ring fit, etc) needs a proper gas port pressure, volume of gas, and dwell time of the gas pressure in order to function the action. Go outside those parameters, and something will not work (in a few cases, that is fine, as I'll illustrate below). Use too fast a burning powder, and while the gas port pressure might be high enough, the faster burning powder didn't generate enough gas volume to work all the moving action parts. Increase the amount of fast burning powder to make more gas and the chamber pressure would exceed the design limits of the firearm (gun can't handle the pressure with a resulting ka-boom) before enough gas volume or dwell time of the gas volume on the action is produced.

    I have a thermal equipped suppressed 300 Blackout AR used for night hunting hogs. I use a proper supersonic load for that. It functions the AR, as fast repeat shots may be needed. I also use it for armadillos. For that I make subsonic 108gr frangible bullet loads using light loads of Bullseye (a fast burning pistol type) powder. Because Bullseye is way outside the norm for use in the Blackout, it doesn't generate the proper parameters of port pressure, gas volume, and gas dwell time to function the AR semi-auto. HOWEVER, that's fine for MY use, as I use the AR as a manually operated rifle, simply pulling back the charging handle and letting go to eject the empty and reload the chamber. Dillos don't travel in herds, don't attack, and the distance is close. Because of the small charge of Bullseye and resulting low pressure, that there is no action opening to release noisy gas out the ejection port, no semi-automatic action noise, and the bullet is going subsonic, it is very quiet. Neighbors don't hear it (they don't care anyway), dogs don't hear it, wife doesn't hear it. In this case, I've went outside the normal operating parameters with the result that the AR doesn't function semi-auto, but that's OK for my use. Another use is with the grand kids...collapse stock to fit them and they fire one shot; can't accidentally fire another shot if they forget and swing the muzzle or another child starts to run forward to reset the target in their excitement. Note: That doesn't happen due to repeating safety instructions, but the manually operated action is yet another safety tool used.

    To further make the situation muddy, I'll toss this in. If one has a SBR/pistol/rifle in Blackout and the firearm is a single shot or bolt action (such as the Remington Chassis Pistol with it's 10.5" bbl), since there is no semi-auto action to be concerned with, it is possible to carefully, thoughtfully go outside the "norm". "Norm" is defined us using the Blackout in an AR or other semi-auto action with loads designed to function the action. Friends and I use fast burning pistol powders with light weight bullets in the Blackout in Thompson Center TC, Handi-rifle, and bolt action rifles for plinking at mild velocities. These are not "full power" loads such as one would use for hog or deer hunting or for hitting targets 100's of yards away. But going outside the norm also means the powder is too fast to generate a "full power" load without exceeding specs for max chamber pressure and perhaps destroying the gun or person in the ka-boom.

    Makers of load data don't know what one will be shooting the cartridge in, so they need to publish data that will work in all guns.
     
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    Zeroed in

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    I'm not in the 300bo club (yet), but I do have a 10.5 in .223. I use regular factory loads which work fine plus there's the added breathing dragon fireballs. :flame:
     
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