Reloading Subsonic .308

EXCRider

EXCRider

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I am thinking about trying some 220 RN Ballistic Tips ( 30181 ) loaded sub sonic in my 308.

Does anyone have relevant experience that would help get me started?

Specific questions:

1) Without any Trail Boss available, case fill will be low. One internet solution is to use a case filler to hold the charge against the flash hole. Some say that this is inconsistent and I have seen some reports of fillers causing chamber damage. Thoughts?
2) I have seen some references to using magnum primers and/or enlarging the flash hole. the theory being that a magnum primer will have enough reach to ignite all the powder, regardless of where it happens to be in the case. Thoughts?
3) Should I just abandon this silly notion and get something more suitable to sub sonic loading and has available factory options, like a 44 magnum, 300 blackout, or 45-70?
 
Trail Boss was a "late comer" on the market for the loads you want to build.

One powder that should fill your case sufficiently and seems to be available in most shops, is H50BMG.

It's a very slow powder, and IMHO, you should use a magnum primer for best ignition.

Lyman manuals show loads with faster, available powders, and velocities around 1050fps, which would be safe.
 
I dabbled with .308 subsonic using Trailboss and even with 215 cast bullets I had to use cotton balls to fill the case and ensure the powder was up against the primer. I used regular primers and left the flash holes the same. I had no issues. Even with a 1:10 twist they were stable. I think the bullet shape of a cast engaged the rifling more than a traditional pointed bullet would.

Don't waste your time and get a cartridge more suitable for subsonic. I switched to 300 Blackout and never looked back. I use H110 for super and sub sonic loads.

I would also consider 44 Mag and 9mm with heavier bullets (147 grain).
 
EXCRider said:
I am thinking about trying some 220 RN Ballistic Tips ( 30181 ) loaded sub sonic in my 308.

Does anyone have relevant experience that would help get me started?

Specific questions:

1) Without any Trail Boss available, case fill will be low. One internet solution is to use a case filler to hold the charge against the flash hole. Some say that this is inconsistent and I have seen some reports of fillers causing chamber damage. Thoughts?
2) I have seen some references to using magnum primers and/or enlarging the flash hole. the theory being that a magnum primer will have enough reach to ignite all the powder, regardless of where it happens to be in the case. Thoughts?
3) Should I just abandon this silly notion and get something more suitable to sub sonic loading and has available factory options, like a 44 magnum, 300 blackout, or 45-70?
Click to expand...
I started loading subsonic 25 years ago before the 300 BLK revolution.

There is no need to use very heavy bullets. Mil surplus 150gr bullets work just fine and are cheap and easy to find.

How would it be possible for fillers to damage the chamber when the cartridge case completely fills the chamber? Cotton or toilet paper can make good fillers. Do not try to use corn meal or something similar. It just mixes with the powder and causes misfires. Just don't use anything plastic as a filler.

Magnum primers are a good idea and I used to enlarge the flash holes when I was using small amounts of fast burning pistol powders. The helps to properly ignite the powder and avoid flash-over of a small powder charge. Modified cases should be marked with a coloured marker to avoid them being used with a full power charge.

The other problem with subsonic loads in a full sized rifle is that it's easy to stick a bullet in the bore. A dirty bore and a longer barrel can easily cause the bullet to get stuck in the bore.

300 Blk is def a better choice. I went that route and never looked back. I've still got subsonic 308 ammo and modified cases but no reason to use them.
 
I had great success with titegroup.
Hodgens has the reloading info online.
It was around 8 or 9 grains. Doesn't seem right but it worked amazing. In winter and summer. Shooting uphill and down.
I was shooting 210 grain, srp brass, pretty sure I even tried small pistol primers and it still worked great.
I also didn't use any fillers.
I see everyone's point about using a 300 blk, but I had such good luck with this load. Pretty sure I shot close to 1000 rounds of it.
And then you still have a rifle with great supersonic performance!
15" barrel, 1 in 8" twist.
Joe
 
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Thanks, guys!

You've certainly gave me some more to think about. Ultimately, I think I will end up buying a different gun just for subsonic. I noticed there isn't many bolt actions (my preference) around that fill the niche. So, a guy would probably have to decide between a tacticool 300 blackout or a lever gun. Or build one.... SO many things to think about.




And to clarify a couple points:
saskgunowner101 said:
Bullet stability in a 308/1 in 10? twist starting at a subsonic velocity is the first thing you need to ask and answer before considering the others.
Click to expand...
I contacted Nosler a while back, they said it is fine in a 10 twist, just to keep the speeds down or else "expansion will be dramatic and excessive." LOL


I Dont Care About You said:
......How would it be possible for fillers to damage the chamber when the cartridge case completely fills the chamber? Cotton or toilet paper can make good fillers. Do not try to use corn meal or something similar. It just mixes with the powder and causes misfires. Just don't use anything plastic as a filler......
Click to expand...
Here are a few threads that mention it: https://forum.nosler.com/threads/case-filling-fiber.7577/ https://www.shootingtimes.com/editorial/fillers-for-reduced-rifle-loads/316610
 
EXCRider said:
I think I will end up buying a different gun just for subsonic. I noticed there isn't many bolt actions (my preference) around that fill the niche.
Click to expand...
There are several options for factory 300 Blackout bolt action rifles.

CZ 600 Trail
Ruger American
Mossberg MVP Patrol
MRA Renegade
Remington 700 - not sure if they still produce this rifle
 
I’ve tried trail boss & tite group, fun to plink around with, magnum primers maybe help keep it consistent? I don’t know. I’ve a couple boxes of Hornady sub x 190’s I haven’t got around to testing yet. Haven’t ever got stellar accuracy yet… under 2 moa but never under 1 moa yet.

I have never used fillers or drilled out the flash holes
 
I been looking at Sub sonic as well, have a Ruger Predator in 308 16 inch 1/10 barrel and I have some trail boss.

Will have to see if it’s worth it to play with or if I should also just go .300 black.
 
Subsonic 308 is very old ground that has been covered for about 60 years. No need to drill flash holes, employ magnum primers, nor use filler, and you certainly don't have to rely on Trail Boss. Use a small amount of very fast pistol powder (e.g. Bullseye, Red Dot, Titegroup or Unique) under the bullet of your choice, being careful to not use bullets heavier than your barrel twist rate can stabilize.

To suppress the sound as much as possible (since the supersonic element is only part of it), use as little powder as possible, i.e. lean towards a small amount of a fast powder. Muzzle blast is the product of muzzle pressure and the volume of gas being expelled.
 
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joehunt said:
I see everyone's point about using a 300 blk, but I had such good luck with this load. Pretty sure I shot close to 1000 rounds of it.
And then you still have a rifle with great supersonic performance!
15" barrel, 1 in 8" twist.
Click to expand...
which 308 rifle Joe? w/1-8" twist?
 
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