New To Loading Sub Sonic

[Possum564]

I have a .308 Winchester 16” barrel with a 1:10 twist. Bolt Action Mossburg Scout.
I would like to use the Hornady SubX projectiles in either 175 or 190 grains. Are those viable or should I go heavier in weight? Would like to use Tight Group and Federal Large Rifle caps. Do any of y’all have any thoughts? I can read the printed load data but just not sure on which bullet weight to start with in a 16” barrel. Load data was created with a 24” . Looking to load subsonic.

 

[BigDaddy0381]

I use the below Bullets with fed 210 primers and trail boss powder and lapua brass.
I have a 26inch 1-10 twist.

Maker bullets: 200 Grain .308 Expanding Subsonic Blackout Bullets (Box Qty - 50), Projectiles, 308200SBLK

 

[roostercogburn98]

I ran some 220 grain Hornady interlocks over titegroup in my 1-11:25 308. Running 3 shot average of 944 fps. Pretty sure that was 10 grains even on the powder load

 

[FuhQ]

I have a .308 Winchester 16” barrel with a 1:10 twist. Bolt Action Mossburg Scout.
I would like to use the Hornady SubX projectiles in either 175 or 190 grains. Are those viable or should I go heavier in weight? Would like to use Tight Group and Federal Large Rifle caps. Do any of y’all have any thoughts? I can read the printed load data but just not sure on which bullet weight to start with in a 16” barrel. Load data was created with a 24” . Looking to load subsonic.

You will want the 190's, and ideally, you will want to use Trail Boss, but it's pretty much non-existent since the Obama ban (nearly a decade now). Luckily I have plenty of it on-hand for my .308 Win subs. However, Tite-Group would work, so would Alliant Power Pro 300-MP and Hodgdon H110. The only problems with the pistol powders, is you will have SO much extra room in the case, that you can get hangfires or FTF's. I would recommend using regular LRP brass with CCI or Federal LRP's to make sure you get a good ignition. I use cheap Federal "FC" brass I pickup at the range, since it's not good for anything else (too soft for high-pressure loads). I recommend using Trail Boss, if you can find some, it takes up more case room because it's a donut powder and has much larger donut-shaped kernels.

 

[redbullitt]

I'd start with the load data listed and work your way down with a chronograph until 1000 or so fps. Do all this work without a suppressor mounted!

If you're planning to hunt, the expanding subsonic bullets are your friends! Otherwise, I've had good luck using 180 sierra round noses and sierra 220 round noses and similar. The flat nosed sierra 170g bullets designed for 3030 also have shot well.

I'd use large rifle primers, maybe magnums. Sometimes it does help. Even changing brands can be a factor on subs.

Sometimes it can be helpful to enlarge the primer hole a bit, BUT YOU MUST KEEP THAT BRASS FOR SUBSONIC ONLY AFTER THAT IS DONE.

A fast fluffy pistol powder will be your best bet. I've had good luck with red dot, titegroup etc. Tipping barrel up, slowly lowering can help consistency, but that's annoying for sure... and I try to find a loading that does ok without that.

Trail boss is best, but so is unicorn dust. Be aware that even though you're loading subs, you will be using high pressure loadings with the fast powders.

Have realistic expectations for subs out of a 308. Under 2 inches at 100yd CONSISTENTLY is doing well. If you get closer to 1 moa then you are really doing a great job loading and shooting.

Driving the rifle right and loading very good ammo and working up a great loading are much more important than with typical full power stuff. It can be done, but you gotta send the best if you want good results!

 

[smoooth1]

Great advice in the posts above!

TiteGroup works great for 308 subs. If yoh haven’t already, check out the “Subsonic” topic in the reloading section, good information there.

Some barrels are much more forgiving than
others when shooting subs and what bullet works great in one rifle may keyhole in yours (why you test unsuppressed, as mentioned above).

Here’s a couple videos that may be helpful??

Good luck!