308 Subsonic Loads

[85t5mcss]

I have been loading 308 with about 46gr of BL-C(2). Recently a friend asked me about subsonic loads for it. So I checked out Hodgdons site and they list 8.0 gr (max) Titegroup or Clays for 308, using 168 gr Sierra HPBT and OAL of 2.800" That leaves a LOT of space in the case that is filled by nothing but air. Raising the barrel to tap the powder back every time is out of the question. Has anybody used fillers and had luck? Pressure signs? Issues with mixing or burning? I researched it all I could and it seems like that is the way to go for black powder but not smokeless. 8.0 gr in a 308 case is near nothing. I know TG burns fast, but just seems extremely light.

Suggestions or ideas? Atomic and Lapua make 308 subs, but I haven't gotten my hands on any yet to see what is inside.

 

[451_Detonics]

I would suggest trying Trail Boss http://www.loaddata.com/articles/PDF/LD-36 Haviland LR.pdf

Here is my Ruger using Trail Boss loaded for sub sonic velocity

[video=youtube;_LF4QpZMeVU]https://www.youtube.com/watch?v=_LF4QpZMeVU&list=UUdeBvJY9-Yy4sUPeLXQcOaQ[/video]

 

[Yeah]

Lapua's subsonic rounds are full of a blended powder from Vhitavouri, but it doesn't match anything they sell to the public. Don't know Atomic's.

EBR-INC sells 308 Win subs over the counter, and they are using Trail Boss. Setpoint does as well and though I've never handled any of them those who have have told me Trail Boss there as well. All the ranchers I know back home in South Africa who use cans during cull hunts and VV's N32C is popular with them in a variety of chamberings.

The only filler I've ever used was kapok. No complaints with it other than slows down the reloading process, and picking the right powder obviates the need for it.

 

[85t5mcss]

Hmm. Trail Boss is loaded at 10.0 grains but 75% fill due to it's shape. I think I better find some Trail Boss to try out.

 

[451_Detonics]

I did try some reduced capacity .308 brass at one point...total pain in the butt to load

 

[j706]

I really like 10.0 Grns of Trail Boss with 175 grn SMK's. It is not only quite but also very accurate.

 

[85t5mcss]

I really like 10.0 Grns of Trail Boss with 175 grn SMK's. It is not only quite but also very accurate.

Probably will be using 168gr SMK HPBT or Hornady 168gr HPBT just because I have so many.

I think these are going to be used for 100yard feral hog hunting at night.

How accurate were your 175gr SMK? At what distance? Did you chrono any of them?

 

[451_Detonics]

I load mostly 190 or 220 SMK but my Ruger is an original 77 with the 1-10 twist barrel and seems to stabilize the heavier bullets quite nicely. I know some 1-12 barrels can keyhole those heavier bullets. Accuracy is excellent at about 1050FPS. Using 13.5 of Trail Boss with a magnum primer to consistently ignite the powder.

 

[j706]

Probably will be using 168gr SMK HPBT or Hornady 168gr HPBT just because I have so many.

I think these are going to be used for 100yard feral hog hunting at night.

How accurate were your 175gr SMK? At what distance? Did you chrono any of them?

At my limited home range of 88 yards with a 18" 1/10 twist Rem.700 surpressed they shoot into one jagged hole. I have not run the speeds. From my Black Hills 175 match zero the subsonic load takes 7 moa of elevation and 1.5 moa left. Sizable difference but very consistent.

 

[85t5mcss]

Ran just a few through an AR-10. Of course it didn't cycle but I didn't expect it to, either. Definitely quieter and near zero recoil. This was with 8.0gr Titegroup and 168gr HPBT. Tapped powder back to primer before firing and for award towards bullet and fired both ways. Did not go through a chrony yet. Just testing for function. Maybe a lighter spring and buffer and I could get them to cycle. Not much sense though. They'll be shot through a couple 700s, a savage and the AR.