300 Blk subsonic query

[Robert H]

Evening all.

I have just acquired a Ruger American in 300 Blk (16.1" barrel, 1:7 twist) with a .308" wildcat Evolution moderator. I have also got some 190gr Hornady sub-x bullets (Can't find factory rounds) and Viht N32C and N110 powders. I have a Chrony F1 chronograph which appears accurate when tested with other calibres, but I can't seem to get the rifle 'quiet'.

I started at 9gr of N110 for 1061fps and I'm now down to 7.4 gr and getting 510 fps but there is still one heck of a crack. It's a loud as an unmodded 22lr firing subs. Just for background I use Winchester 42gr 22lr subs in a CZ455 and Logun moderator which are pretty quiet and CCI quiet segmented (710 fps) rounds which are super quiet. (quieter than my rapid 7) And I know I'll never replicate that level of quiet.

But, a shooting friend brought a box of the 190 sub-x's and his 26" barrelled 300win mag round last summer so we could develop a subsonic load for him. (I know, I know) and it was on the basis of the load developed using N32C doing just under 900fps, which was firing pin quiet, that made me put in for a 300blk. I'll quickly say here N32C is no quieter in the Blk and also produces heavily externally sooted cases. So what's going on? Am I expecting too much or is the Moderator unsuitable? (I have an EVO on my .223 which is great but when transferred to the 22lr is actually louder than the Logun) Am I using too fast a powder or what? I am at a loss and would very much appreciate your thoughts.

Thanking you in advance.

 

[phaedra]

I have the same rifle, not great quality out of the box, badly machined bolt and a flexible stock

Also the supplied magazine is a 223 not 300BLK, swapping that to a proper mag (improved internals) improved feeding with the larger .30 bullets.

I fitted mine into a Trybe chassis, big improvement in handling and accuracy.

I shoot mine using both sub and super sonic loads.

For supersonic I use 17gr of Viht N120 with a Lapua 167gr Scenar

For Subsonic I use 3.8gr of Viht N310 and a Shellhouse 170gr cast, runs around 920fps

Never bothered with the moderator, I shoot the subs indoors at 25yds and it's not as noisy as a 22LR anyway.

 

[Andy RV]

If you’re still getting a crack perhaps your chronograph is reading off at these low velocities and you’re still supersonic?.. although the saying that you’ve very low at 7.4gr of N110…

In other words, I don’t know!

My 308 with a Ase Jet Z is very quiet with Lapua 200gr subsonic bullets and a sprinkle of unique.

 

[Robert H]

I have the same rifle, not great quality out of the box, badly machined bolt and a flexible stock

Also the supplied magazine is a 223 not 300BLK, swapping that to a proper mag (improved internals) improved feeding with the larger .30 bullets.

I fitted mine into a Trybe chassis, big improvement in handling and accuracy.

I shoot mine using both sub and super sonic loads.

For supersonic I use 17gr of Viht N120 with a Lapua 167gr Scenar

For Subsonic I use 3.8gr of Viht N310 and a Shellhouse 170gr cast, runs around 920fps

Never bothered with the moderator, I shoot the subs indoors at 25yds and it's not as noisy as a 22LR anyway.

Yes indeed, the rifle is rough out of the box. A fine file on the bolt burrs, a good degrease to get rid of whatever gunk they ship them in, and a liberal squirt of Ballistol Guncer oil on the bolt and Guncer grease on the lugs has completely transformed it. I was tempted to blame the Magpul magazine at first for the awful sticky action, but the fettling and lubrication proved the mag is fine although I did buy an extra Lancer mag in 300blk.

Apart from the short length of pull it's a handy rifle.

 

[Robert H]

If you’re still getting a crack perhaps your chronograph is reading off at these low velocities and you’re still supersonic?.. although the saying that you’ve very low at 7.4gr of N110…

In other words, I don’t know!

My 308 with a Ase Jet Z is very quiet with Lapua 200gr subsonic bullets and a sprinkle of unique.

I know opinions differ on the Crony F1 but mine seems to check out with my other rifles. I might go lower but I'm concerned about a bullet sticking in the barrel.

'Tis most perplexing.

 

[xavierdoc]

I found Trail Boss produced quieter subsonic 300Blk loads than DO63. I don't know the reason as both were subsonic. Presumably something to do with gas velocity (ahead of bullet) or unburnt/still burning powder at the muzzle. I haven't compared Tin Star side by side but don't think it was as quiet as TB.




Trail Boss has been banned in UK and TinStar is being phased-out so I'm on the look out for Reload Swiss RS14: low bulk density for similar applications to TB and Tin Star. How it fares in comparison of noise remains to be seen.

 

[ashray]

i think it a case of a short barrel <16.1 " and the evo mod ,try a heavier mod and if you can >buy any some trail boss

 

[Robert H]

I found Trail Boss produced quieter subsonic 300Blk loads than DO63. I don't know the reason as both were subsonic. Presumably something to do with gas velocity (ahead of bullet) or unburnt/still burning powder at the muzzle. I haven't compared Tin Star side by side but don't think it was as quiet as TB.




Trail Boss has been banned in UK and TinStar is being phased-out so I'm on the look out for Reload Swiss RS14: low bulk density for similar applications to TB and Tin Star. How it fares in comparison of noise remains to be seen.

Interesting information and video. Thanks for posting it. I thought about trying to record my rifle with my phone to demonstrate, but the inbuilt compression renders the final results pointless.

 

[Robert H]

i think it a case of a short barrel <16.1 " and the evo mod ,try a heavier mod and if you can >buy any some trail boss

I think you may be right, and I'll look out for some trail boss, but it sure is a disappointment!

 

[Robert H]

What I have noticed in my very short foray in firearms (and I bow to far more experienced users than me) is that perceived noise levels are not only subjective, but are obviously situational. By that I mean using the same combination of rifle and cartridge can sound (to the shooter) totally different when shot from prone, from a high seat, in woodland or off a hillside with little to reflect the report.

Perhaps I am on a hiding to nothing.

 

[Bigboab29]

I’m currently using 220gr nosler subsonics with 9gr of hodgdons h110 and it’s really quiet, majority of the noise comes from the massive bullet thumping the target, running low on the noslers, couldn’t get any more so bought a load of 190gr sub x, hopefully I’ll get similar results

 

[Robert H]

I’m currently using 220gr nosler subsonics with 9gr of hodgdons h110 and it’s really quiet, majority of the noise comes from the massive bullet thumping the target, running low on the noslers, couldn’t get any more so bought a load of 190gr sub x, hopefully I’ll get similar results

Hopefully you will. I wanted H110 but can’t find it for love nor money.

 

[Bigboab29]

Henry krank usually has it in stock, my local rfd has an account with them and I just got him to order it in for me, I think you can get it delivered but there’s a hefty delivery charge on it!!

 

[Robert H]

Henry krank usually has it in stock, my local rfd has an account with them and I just got him to order it in for me, I think you can get it delivered but there’s a hefty delivery charge on it!!

I’ll check that out, thanks!

 

[Muir]

I use 8 grains of Lil Gun. ~Muir

 

[pjkaz]

I'm using Viht N110 7.9 gr with a hornady 225 ELD match bullet 16 inch barrel 1.8 twist . VERY QUIET

 

[hunta]

I started at 9gr of N110 for 1061fps and I'm now down to 7.4 gr and getting 510 fps but there is still one heck of a crack

I'm using 9g of H110 and 8g of Lilgun behind Nosler 220g bullets for about 1040fps. These are pretty quiet in my Rem 700 with 16" barrel. When l was developing a subsonic load there was a very big difference between supersonic and subsonic.

 

[Robert H]

Resurrecting this thread of last year by reporting that my 300blk subsonic problems lay in the moderator. A change from the appalling factory stock of the Ruger American Ranch to a Magpul Hunter stock forced me to swap the Wildcat Evolution for a Ase Ultra Jet-Z and hey presto, I now have a lovely quiet rifle, and a low shot count Wildcat Evolution in .308 for sale.

 

[phaedra]

Good news

Mine is currently only getting used with supersonic ammo as ShellHouse no longer supply the bullets I want "as cast"
They only supply them with a gas check and lube which has doubled the price

ShellHouse do make a coated 175gr BTHP profile cast bulet but it's not as accurate as my usual choice.

175 Grn 30 CAL POLYMER COATED HEAD — ShellHouse Castings

This is a Polymer Coated head that can be used as a replacement for our Gas Checked product, and compliments our growing range of Polymer Coated Rifle bullets.

shellhousecastings.com

I can get some very nice polymer coated from the EU but I'd have to fly over to collect as they won't ship outside the EU.

Taking it out Sunday to re-Zero it at 100yds, hopefully not raining!