Barrel length sweet spot for suppressed 308?

[snod85]

I have a little used Remington 700 in my safe. I’m converting it to a dedicated 308 subsonic rig. Have a 1:7” blank ordered.

Hope to shoot Berry 220s and trail boss powder. While searching found the accurate reloader blog had done similar with promising results.

Using a Banish 30 can.

Just looking for input on noise levels vs barrel length on big suppressed subsonic 308 bullets.

Considering from 16” to 20”.

Anybody done this drill before and have advice? Specifically, will the 20” be noticeably quieter than the 16”

Thanks.. it’s the kind of thing I’ll only do once but would like to do it right.

 

[GetReal]

I think all that is the point of 300BLK... a subsonic 30 cal bullet.

A heavy bullet with reduced powder in a relatively small case. Typical 308 case with the minimal powder youd need to use risks turning the case into a mini bomb..

Not sure I ever seen an efficient sub 308.

 

[Sniper338]

I have a 20. I dont think there will be any difference in noise with barrel length.

I can tell you though I'd go to 16 because 20 is too long with a can still for me at least. I have a 9 inch thunder beast though.

 

[longrangehunterII]

18.5” 1:9 twist. The threaded portion is buried in the suppressor, so it’s basically like an 18” inch barrel. I get 2625 with the 169 SMK’s behind H4895.

 

[1shot]

Mine is a 16.5" bbl. 1-8 twist and works well.

 

[kelbro]

If you are going subsonic, 300BK is the answer. Loading down 308 would be much less efficient. I have a lot of TrailBoss but it was very hard to find for quite a while.

My 16" 300BK barrel is very quiet.

 

[mattri]

Ran a 16" 308 subsonic for a while with good results

Trailboss is a good powder but I had success with others as well. I was concerned about case fill etc but never had any issues, even when intentionally tipping the rifle one way or another trying to unsettle powder and/or at various temps. You'll have to do your own load work up like normal but it is certainly doable.

If you do decide to ever run it super be mindful of the blast that short barrel will create

 

[GetReal]

If you are going subsonic, 300BK is the answer. Loading down 308 would be much less efficient. I have a lot of TrailBoss but it was very hard to find for quite a while.

My 16" 300BK barrel is very quiet.

Before I started using BP, I loaded my 45-70 with TB. I havent seen TB in years.

 

[kelbro]

Before I started using BP, I loaded my 45-70 with TB. I havent seen TB in years.

I just read that it's back available after a long drought.

 

[snod85]

Thanks guys.

I have a ton of Trail Boss and 308 brass and the barrel blank is on order. Trail boss should be fine in getting a complete burn in a 16" barrel but if there was real life experiences out there that indicated 20" was significantly quieter I was prepared to go up to 20". The only reason (to me) to do this is to maximize noise reduction.

Have read about velocity drop offs on strings between cleanings with jacketed bullets but it seems cast bullets may mitigate this somewhat. Will be a fun load development experiment. I've used Berry's before and been pleased so I'll start there. If I'm going slow might as well go big.

What I'm hearing from the board thus far is the shorter barrel will be as quiet as the 20" provided I use the fast/pistol powders around trail boss to get complete powder burn in barrel.

Still interested if someone has had a different experience.

 

[mattri]

Thread 'Subsonic 308 without trail boss'

Sep 14, 2023

Looks like Trail Boss is history, but then I also heard tb is not very accurate in subsonic 308 anyway. I found a load of 150's with Titegroup, but it's so compact I doubt it will ignite reliably. So that leaves bulky flake powders like Clays and Blue Dot. Does anyone have advice for 168 Eldms? (R700, 24 inch 5R barrel, no can)

• ScottMcc
• Replies: 111
• Forum: Big Stuff--7mm, 30 Cal, .338+

• 

 

[k260]

Typical 308 case with the minimal powder youd need to use risks turning the case into a mini bomb..

That's the purpose of using Trail Boss powder, it's bulky so it doesn't require a case filler and doesn't cause pressure issues like a typical small charge of rifle powder.

 

[GetReal]

That's the purpose of using Trail Boss powder, it's bulky so it doesn't require a case filler and doesn't cause pressure issues like a typical small charge of rifle powder.

TB has been unobtanium for years. Others said the same above, claiming its coming back around. Im not seeing it ANYWHERE. I Wouldn't wanna build a whole gun contingent on using only one powder , And then having availability of that powder disappear ... while also having that one powder not necessarily produce accurate groups for me. I'd Rather , have three or four powders readily available to choose from.

But thats just me.

Besides , this concept already exists in 300BLK.

Buy hey... people are absolutely free to build whatever they want.

 

[k260]

TB has been unobtanium for years. Others said the same above, claiming its coming back around. Im not seeing it ANYWHERE. I Wouldn't wanna build a whole gun contingent on using only one powder , And then having availability of that powder disappear ... while also having that one powder not necessarily produce accurate groups for me. I'd Rather , have three or four powders readily available to choose from.

But thats just me.

Besides , this concept already exists in 300BLK.

Buy hey... people are absolutely free to build whatever they want.

It's possible he has a supply, I have an 8# jug that'll probably last me forever. I have a 330 Blk and a 308 set up for subsonic, they both have a specific purpose so the 300 Blk isn't always the answer. But, even if he has to use a different powder all he has to do is use a case filler, everything isn't a bomb.

 

[GetReal]

It's possible he has a supply, I have an 8# jug that'll probably last me forever. I have a 330 Blk and a 308 set up for subsonic, they both have a specific purpose so the 300 Blk isn't always the answer. But, even if he has to use a different powder all he has to do is use a case filler, everything isn't a bomb.

So you re just gonna argue with every single thing I say.

Lifes too short. Im moving on.

Have a nice nite.

 

[snod85]

Appreciate the replies. I do have a bunch of trail boss and I don’t shoot my 45c pistols much anymore. It’s a fun powder to play with but this subsonic experiment will be only the second thing I could possibly use it in. Also have more starline 308 brass than I’ll ever use. With having a little used rem 700 it just seems to be a fun little project. I bet I learn something even if it does not work out perfect.

I mainly just wanted to be reassured I wasn’t bumping the noise too much by staying just over 16” on the barrel.

Will put an lpvo or an old night vision scope on it and maybe police the coyotes around the house with it. Already lost one jack russell to them and the current one is just as hardheaded. I have stuff for daytime and for the pastures, but around the house in the woods it might work after dark and not startle the neighbors.

Thanks

 

[k260]

So you re just gonna argue with every single thing I say.

Lifes too short. Im moving on.

Have a nice nite.

If you said anything that made sense I wouldn't, I did notice you didn't disprove anything I said....

 

[GetReal]

If you said anything that made sense I wouldn't, I did notice you didn't disprove anything I said....

IM sent.

 

[LPToes]

I've used Red Dot in .308 reduced loads, can't remember the charge. My 700 is a 1:11.25 / 20", and won't shoot anything above 165/168 weight at those low speeds. Would only be worth the trouble if the .308 was sole rifle.

Agree the .300 AAC is better for subs with heavy bullets in .30 cal. And I use Win. 748, which is available.

Suppressor makes bolt cycling loudest thing in my .300 AR. Tin cans and paper targets never hear the thing coming, which is good, because the sound would get to the target first.