Topic: HOW TO HANDLOAD SUBSONIC RIFLE CARTRIDGES

[J Mack]

I’m doing some research for a project and thought I would share this information.
 
Part 0ne Link: http://guns.connect.fi/gow/arcane1.html

Part Two Link: http://guns.connect.fi/gow/arcane2.html

Part Three Link: http://guns.connect.fi/gow/arcane3.html

[Lefty_OMorrow]

I've been doing some similar research. Have you investigated TrailBoss powder in a .308?

http://www.benchrest.com/forums/showthread.php?t=63450

http://www.eotacforum.com/viewtopic.php?f=15&t=60221

I'm still waiting to finish a couple more projects before getting a Savage .308 to start playing with that.

Would love to hear your plans.

[RGinIdaho]

Round lead balls and a couple of grains of bullseye in the 30-30 and you are good to go...

Paco Kelly used to write about these.

Put some together years ago. Well, I better quit while I'm ahead...

[J Mack]

I've been doing some similar research. Have you investigated TrailBoss powder in a .308?

http://www.benchrest.com/forums/showthread.php?t=63450

http://www.eotacforum.com/viewtopic.php?f=15&t=60221

I'm still waiting to finish a couple more projects before getting a Savage .308 to start playing with that.

Would love to hear your plans.

Lefty

Great minds think alike!
Trail Boss looks like the hot setup for the .308 subsonic loads.
I’m still working out some details for the rifle but it looks like I will probably build an 18” barreled .308 in a billet folding stock for an ultra compact quiet package.

[TrooperBrian]

I was going to wait to make this thread until I picked up a suppressor, so thanks for the thread Jim!

[J Mack]

I was going to wait to make this thread until I picked up a suppressor, so thanks for the thread Jim!

I listed the sites above more as a fun read loaded with cool facts.
Please before you try to load a modern rifle cartridge with pistol powder do your homework.
Some things to look at, Secondary Explosive Effect (SEE) and bullets sticking in the bore.
http://members.shaw.ca/cronhelm/DevelopSubsonic.html

http://members.shaw.ca/cronhelm/762ProjectRifle.html

[technique]

8.5gr. Trailboss
LC brass
30-30 cal. .308dia 170gr Sierra FN
CCI primers

= 885fps

The sweet spot for me was around 9.5gr. going just over 1000fps., same materials.
Once I got into 10-11gr. I was around or above 1100fps and no longer subsonic.

[technique]

.....also, it's recommended you do not crimp these subsonic loads. I did a light crimp for an auto loader and all was well.

[TrooperBrian]

8.5gr. Trailboss
LC brass
30-30 cal. .308dia 170gr Sierra FN
CCI primers

= 885fps

The sweet spot for me was around 9.5gr. going just over 1000fps., same materials.
Once I got into 10-11gr. I was around or above 1100fps and no longer subsonic.

I'll keep that in mind! I hope to be handling some suppressed goodness here pretty soon.

[TrooperBrian]

Thanks Jim for the great info on SEE too..

I'll probably be starting with some Bullseye, I have tons of it.

[TrooperBrian]

Has anyone tried the Bullseye load? It would seem to me that 7.0gr fills a dangerously small amount of the case.

[zona5101]

i have successfully loaded 168g bthp using titegroup. iirc it was in the 8 g area. it was fairly accurate at 100y (3' group), some evidence of keyholeing. Fun to dink with but not enough accuracy for precision marmot work.

[sheepdog1]

there are susonic loads on just about every powders website. just make sure you see bullet inpact . no they arent accurate bullet weight will be a factor and will not operate a gas gun no matter how many times you see it in the movies

[TrooperBrian]

i have successfully loaded 168g bthp using titegroup. iirc it was in the 8 g area. it was fairly accurate at 100y (3' group), some evidence of keyholeing. Fun to dink with but not enough accuracy for precision marmot work.

I read not to use Titegroup because the nature of that double base powder makes SEE much more likely. 

[technique]

I read not to use Titegroup because the nature of that double base powder makes SEE much more likely. 

That's why I like the TB...it's fluffy, a lot of powder weighing very little. Fills 'em up.
Worth the $16...works for .223 also.

[J Mack]

Ok I just picked up some bullets and I’m impatient and don’t want to wait until I finish my 1-10 twist barrel and decided to do some testing today but it’s too cloudy to use the crono so I’ll have to wait for a better day to resume.

Bullet: 220 GR Hornady round nose
Laupa Brass
14 GR of Trail Boss powder
Win Mag primer
.308 /18” tight bore barrel 1-11.5 twist

I started with a higher start load of 14gr’s of TB with the intent of working down as recommended but stopped here until a better day. This load exceeded my expectations and shot two groups under an inch @ 100 and seemed reasonably quiet even shooting from inside my shop.