.243win sub sonic

[rhino519]

I would like to come up with a subsonic round for .243win
what are the rules when working on a load like that? pick a heavier gr bullet or lighter? will a rifle with 1:10/ 1:9 twist have any success in stabilizing a round?
I know the question about subsonic rounds was asked here before and it got me thinking about working one out for my yote gun.

 

[skypilot]

A heavier(longer) bullet wont stabilize at 1000 fps in a 10 twist.
More like a 75-80 gr or less, you can run the stability calcs and come close to what will work.
Pistol powders are worth looking at.

I'd be skeered, like real scared of reduced load stick and medium or slower powders.
You gonna use jacketed or cast?

I would want a hot primer.

Developing subs can get one easily hurt but can be done, i think there is even load data published nowdays for some loads/cal.
Bootlegging subsonics is test pilot chit. A mistake won't be kind and likely debilitating, so do lots of research and keep your wits about you more so than normal reloading.

Sorry, that's about all I'm willing to say. Just be careful.

 

[rhino519]

thanks sky
maybe ill put it on my future projects list, for now, im brind new to reloading

 

[hometownhero]

Trailboss and any bullet you want. I have some 165gr 30-06 loads at 1200 fps. Can load them lighter as well. Also loaded some in the 223 and was getting around 1000-1100 fps with trailboss

 

[battered]

just do not compress trailboss. As old mate above says but heavier pills wont work. its pretty easy to have a quick check if it will on a bullet stabilization calculator on google search

 

[Northman999]

I use trail boss in several cases for reduced recoil loads and small game loads.

Works great.

Never compress it.

You can reduce your velocities WAY down if you want to.

I have some TB loads for knocking over grouse and rabbits that loaf along at just over 500 fps, and shoot cloverleaf sized groups at 25 meters.

 

[rhino519]

thanks guys,
played around with the bullet stability calculator (thanks battered) it seems that with a 1:9 twist rate lighter bullets will stabilize better and give better BC, i can go as far as 1200fps mv with a 65gr pill, just above sonic boom, however just double checked my rifle specs and it is 1:12 twist rate and i have to hit 1800fps and only marginally stabilized dont think its worth it

 

[WeakKnee]

I use trail boss in several cases for reduced recoil loads and small game loads.

Works great.

Never compress it.

You can reduce your velocities WAY down if you want to.

I have some TB loads for knocking over grouse and rabbits that loaf along at just over 500 fps, and shoot cloverleaf sized groups at 25 meters.

I have been interested in developing a light Trailboss Jacketed Bullet load for grouse while hunting big game, do the loads make much noise? Would it be comparable to a sub-sonic .22lr round? Thanks, WK

 

[hometownhero]

I have been interested in developing a light Trailboss Jacketed Bullet load for grouse while hunting big game, do the loads make much noise? Would it be comparable to a sub-sonic .22lr round? Thanks, WK

I have some loads for my 30-06 that are 1200fps. I can load them lighter then that as well. This is with a 165gr bullet as well. Recoil is nothing at all and very quiet. I think the 1200fps ones I have loaded are quieter then a 22lr

 

[Suputin]

I've done a lot of work with subsonics and I discovered that a subsonic requires a much higher stabilization factor than a supersonic. Even then it highly depends on the weight distribution of the bullet. For example a 30 cal 168gr HPBT bullet is really difficult to stabilize because all the weight is at the back end.

Also, BC's at less than sonic velocity are way higher than the typical BC posted for the same bullet at supersonic velocity.

When it comes to flight noise, anything over the speed of sound will produce the same sound level. Once the bullet has exceeded the speed of sound, the noise does not increase with velocity.

Trailboss is an excellent powder choice as it is very fluffy and will help fill the case. Regardless you should NEVER load any powder to less than about 30% of case volume.

I'd be cautious about loading subsonic 6mm in a long barrelled rifle. The 6mm bullet will have proportionally much larger surface area to weight, which will vastly increase the potential for getting the bullet stuck in the bore. A long barrel will also increase the chances of sticking a bullet. You would for sure need to lube the bullets and make sure you have a clean bore. Otherwise ......

This is one I did.

 

[Northman999]

I have been interested in developing a light Trailboss Jacketed Bullet load for grouse while hunting big game, do the loads make much noise? Would it be comparable to a sub-sonic .22lr round? Thanks, WK

Depends on lots of things.

I have subsonic 9mm and 45 acp loadings for carbines that shoot with no more noise than a .22 subsonic, but are sledgehammers on small game.

I have bigger cartridges that are a bit louder, but not too much.

I just developed a 9.3 x 62 load using 285 grain cast, Trail Boss and some Dacron filler, and it makes less noise than regular .22 lr, but a bit more than subsonic. That one is particularly accurate, and shoots close to cloverleafs at 25 meters.

I've never looked at twist calculators or whatever; I do up about ten rounds of something and just go try it. Technically, I'm not sure if my 9.3 x 62 should stabilize a 285 grain bullet at only about 600 fps, but it does...