reloading Sub-Sonic 308 Win. with light bullets

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Oldhandloader

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To begin, I am almost 68 and started reloading when I was 20 something so I'm not new to reloading but I know when to ask for information.
I am trying to develop a safe load with a pistol powder (Bullseye) pushing a 125 grain hollow point in a .308 Winchester bolt action gun and a 25" barrel.
I have established that 7.2 grains of Bullseye with a 168 gr. Moly coated Sierra MK and modified cases (flash hole drilled out) work very well and run about 1000 fps.
So, I am guessing that something around 5.4 grains of Bullseye with the 125 grain H.P. might be close.
If any of you guys have a recommendation let me please hear from you.
 
We should never guess on powder charges because pressures are unpredictable. What sounds safe could be dangerous because pressures do not build linearly.

Hodgdon supplies data for reduced loads for many rifle cartridges using H4895 and all are pressure tested and safe. You should look there if you can't find published data with pistol powders. The older loads were made with SR 4759 and it worked very well. Trail Boss is supposed to be it's substitute.

Edit: Here is the link for data on reduced H4895 loads.
http://www.hodgdon.com/wp-content/uploads/2016/11/h4895-reduced-rifle-loads.pdf
 
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We should never guess on powder charges because pressures are unpredictable. What sounds safe could be dangerous because pressures do not build linearly.

Hodgdon supplies data for reduced loads for many rifle cartridges using H4895 and all are pressure tested and safe. You should look there if you can't find published data with pistol powders. The older loads were made with SR 4759 and it worked very well. Trail Boss is supposed to be it's substitute.

Hodgdon will have 2 subsonic charges on its reloading website for 168 gr SMK one is definitely with trail boss, Bullseye is an Alliant powder they may have that data as well. I wouldn't guess either and would look at both powder manufacturers websites for this data.
Dom
 
Hodgdon will have 2 subsonic charges on its reloading website for 168 gr SMK one is definitely with trail boss, Bullseye is an Alliant powder they may have that data as well. I wouldn't guess either and would look at both powder manufacturers websites for this data.
Dom

Brother Dom
Thanks for the info....and believe me, I wasn't going to cobble something together without good published data. Been around too long for that. I was hoping that someone out there would have had some specific and legitimate source for that 125 grain Speer varmint bullet. I am running a suppressor on this rifle so that is the reason I am going subsonic---coyotes, etc.
Thanks
The Oldhandloader
 
Brother Dom
Thanks for the info....and believe me, I wasn't going to cobble something together without good published data. Been around too long for that. I was hoping that someone out there would have had some specific and legitimate source for that 125 grain Speer varmint bullet. I am running a suppressor on this rifle so that is the reason I am going subsonic---coyotes, etc.
Thanks
The Oldhandloader
No subsonic load data posted for a 125 gr projectile on either alliant or Hodgdon's websites. Might be too small of a projectile/too much case capacity to push a projectile that small subsonic. I am traveling so dont have the speer manual in front of me. Do you have a speer manual?
Dom
 
Why do you want subsonic loads?

Light bullets in a big case at subsonic speeds all work against each other. I've tried 6.5g Red Dot in .308 and with a 200g bullet, I get 1000 fps. With a 113g bullet, I get 1310fps. They all shoot well at 50 yards, but you just can't go that slow with a light bullet.

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You might be able to do this if you got down to handgun charges with a smaller case like a 30 carbine if you seated the bullet very deeply or even up against a couple grains of powder, but to get enough pressure to burn cleanly (9-10,000 psi) you will launch that light bullet past the speed of sound. A heavy bullet will work much better if you want to stay subsonic and will not give you very much recoil.
 
I have had good results with Trailboss (11.0 grains) and 150 grain cast/coated bullets.
 
Why do you want subsonic loads?
I would have phrased the question, "Why do you want lightweight bullets?" If you are going to keep the speed down around 1000 fps, why not a heavier bullet? What's the twist rate of your barrel?
 
I would have phrased the question, "Why do you want lightweight bullets?" If you are going to keep the speed down around 1000 fps, why not a heavier bullet? What's the twist rate of your barrel?

You are right, I thought that with the OP citing his age he might be wanting low recoil rather than subsonic for quiet shooting. Mind you that even with uber-light loads or subsonic loads, if you don't use a supressor, the blast from the end of the muzzle is still pretty loud.
 
Why do you want subsonic loads?

Light bullets in a big case at subsonic speeds all work against each other. I've tried 6.5g Red Dot in .308 and with a 200g bullet, I get 1000 fps. With a 113g bullet, I get 1310fps. They all shoot well at 50 yards, but you just can't go that slow with a light bullet.

View attachment 786024
View attachment 786025

You might be able to do this if you got down to handgun charges with a smaller case like a 30 carbine if you seated the bullet very deeply or even up against a couple grains of powder, but to get enough pressure to burn cleanly (9-10,000 psi) you will launch that light bullet past the speed of sound. A heavy bullet will work much better if you want to stay subsonic and will not give you very much recoil.
Why do you want subsonic loads?

Light bullets in a big case at subsonic speeds all work against each other. I've tried 6.5g Red Dot in .308 and with a 200g bullet, I get 1000 fps. With a 113g bullet, I get 1310fps. They all shoot well at 50 yards, but you just can't go that slow with a light bullet.

View attachment 786024
View attachment 786025

You might be able to do this if you got down to handgun charges with a smaller case like a 30 carbine if you seated the bullet very deeply or even up against a couple grains of powder, but to get enough pressure to burn cleanly (9-10,000 psi) you will launch that light bullet past the speed of sound. A heavy bullet will work much better if you want to stay subsonic and will not give you very much recoil.


Just wanted to see how unobtrusive the report is from a 125 grain bullet, at subsonic velocity, and how accurate it is for close varmint shooting.
At my age what else is there to do?
 
I would have phrased the question, "Why do you want lightweight bullets?" If you are going to keep the speed down around 1000 fps, why not a heavier bullet? What's the twist rate of your barrel?

Twist rate is 1/11.5. All I'm trying to do is to see if anyone else has had the same quest and what the answer is.
Thanks.
Old Handloader
 
The biggest problem with a light bullet in a .308 case is that you have a really tough time shooting it that slow unless you use something like compressed air :)
In reality, shooting 10g of fast pistol powder for a 1300 fps MV with a 100g bullet is about as loud as a 22 magnum if you don't have a suppressor. Even at supersonic speeds, you won't hear the crack of the bullet any more than you'd here the blast of the bullet leaving the muzzle. The supersonic crack is heard along the path of the bullet, not behind it. Of course you'll hear the crack as it echoes along it's way just like with 22LR's going through a rifle.
 
Twist rate is 1/11.5. All I'm trying to do is to see if anyone else has had the same quest and what the answer is.
Thanks.
Old Handloader
Right. That rate of twist will make it hard to stabilize heavy bullets at subsonic velocities. Probably need a 1:10 for anything over 175 grains.
 
... The supersonic crack is heard along the path of the bullet, not behind it. ...

Part of of my army training was to go into a deep trench while 5.56 rounds were fired over our heads at night.
We had to peek over the ridge to see the flash which gave a good location of the shooter.
Then after hearing the supersonic crack
Start counting really fast one mississippi ,two mississippi.....
When you heard the pop of the weapon gave you the yardage.
This only works if the bullet missed you...
 
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