Sub sonic velocities ?

[Gordon]

I wonder what is every ones target velocity to ensure subsonic loads ? Shooting for 1050 fps seems like the standard deviation and barrel length .would get you a few surprise sonic booms . I would imagine under 1000fps load data for .300 AAC with 220 grain bullets in 16" barrels would certainly be sub sonic in 8.5" barrels, but not inversely . Same in 147 9mm . Getting ready to set up Dillon for a run of 220 Sierra BTHP seconds at 2.25" OAL over 9.7 grains of H4227 in Starline brass with Rem Primers.
My son is rolling out 147 grain loads over AA9 that do just over 1000 fps in the Ruger PCC Charger 6" barrel so I would presume they will do less in his threaded pistols with shorter barrel.
The thing is he would like to be able to shoot a deer with a .300 BO subsonic load with a great hit that are in his garden at night , during hunting seasons with out waking neighbors (more than 1/4 mile away) with an errant sonic boom . A 220 grain sierra at 1000 fps has around 500 foot pounds of energy so should have enough penetration to get her done (and those long bullets are apt to tumble on impact) but dropping to 900fps or less is sketchy .
Any experience on developing such loadings ?

 

[JeffG]

I keep my .308 subs around 950fps, (estimated) I use 180 gr round nose Sierras, that I moly coat. No evidence of tumbling, shot into plastic jugs of water, but really no expansion, either. Accuracy is great.

 

[gotboostvr]

I keep my .308 subs around 950fps, (estimated) I use 180 gr round nose Sierras, that I moly coat. No evidence of tumbling, shot into plastic jugs of water, but really no expansion, either. Accuracy is great.

What load are you using?

 

[jmorris]

Depends on what my goal is. I have loaded subs slow enough that I could see the bullet going down range. Division PF was 125 and 230’s only had to be going 544 fps to make PF. The joke was “the rule book doesn’t say the bullet has to go all the way through the cardboard target to count…”

If I am using the ammunition for hunting, they are very close to super and about as heavy as I can get.

 

[mcb]

I have two loads I use in my 300 BO guns. I have a 16-inch, 9-inch, and 5-inch. Unfortunately I don't have chrono data for the 5-inch yet. I just got it running late last year.

220gr Barry Spitzer plated bullet
10.1 gr IMR 4227
16-inch: 1040 fps
9-inch: 983.8 fps

220gr Maker Rex all copper bullet
10.4gr Accurate 1680
16-inch: 1060 fps
9-inch: 972.2 fps

This summer I plan on bumping up those loads so they are closer to 1050 from the 9-inch gun and will live with what every they are from the 5-inch gun. I don't use the 16-inch gun much but I have good subs for it and will likely work up a good super load bases on the Barnes TAC-TX 110gr or 125 gr bullet.

 

[JeffG]

What load are you using?

To be clear, all reloading and firing of reloaded ammunition using this data is done at your own risk, This author assumes no liability for death, injuries, or damage due to the use of this, or any other load data.

Hornady Match brass; flash hole drilled out to 9/64". This brass is never used for anything else. One load I settled on was 9.0grs of Unique, after using a downward ladder from 13.1 grs Unique. I use CCI LRP. It crowds the sound barrier, just a bit.
My quietest load is 7.0grs of TiteGroup, on the modified brass as above. Bullets are 180gr Sierra round nose, tumbled with moly and steel BB's.
Bullets are loaded to standard length, without crimp.

 

[mavracer]

I have a 16" bolt and 10" and 8" ARs I load totally different loads that are right at 1050. The bolt gets Unique and 208 Amax or 200 Makers the ARs get 190 subx or Amax with aa5744

 

[Gordon]

I have two loads I use in my 300 BO guns. I have a 16-inch, 9-inch, and 5-inch. Unfortunately I don't have chrono data for the 5-inch yet. I just got it running late last year.

220gr Barry Spitzer plated bullet
10.1 gr IMR 4227
16-inch: 1040 fps
9-inch: 983.8 fps

220gr Maker Rex all copper bullet
10.4gr Accurate 1680
16-inch: 1060 fps
9-inch: 972.2 fps

This summer I plan on bumping up those loads so they are closer to 1050 from the 9-inch gun and will live with what every they are from the 5-inch gun. I don't use the 16-inch gun much but I have good subs for it and will likely work up a good super load bases on the Barnes TAC-TX 110gr or 125 gr bullet.

This really helps, thanks ! I was gonna set the Dillon at 10 grains of IMR 4227

 

[N555]

My subsonic 9mm do pretty close to 1,000fps for my 147gr load and about 1,050 for my 124gr load. And my 45acp loads are typical 230gr 45acp speed.

 

[Gordon]

In ear tests only , Hammer fired pistols SEEM slightly quieter than Striker fired , same ammo and same barrel length .

 

[FL-NC]

I used Hornady sub-x through a suppressed 16" barrel on deer with mixed results- 1 lost, 1 found, 25 yards(ish) distances, and poor to nonexistent blood trails in both cases. The gun used is very accurate inside of 50 yards (x bow archery ranges). In the future, the 300 BLK will only be used on doe days with neck shots.

 

[Gordon]

I used Hornady sub-x through a suppressed 16" barrel on deer with mixed results- 1 lost, 1 found, 25 yards(ish) distances, and poor to nonexistent blood trails in both cases. The gun used is very accurate inside of 50 yards (x bow archery ranges). In the future, the 300 BLK will only be used on doe days with neck shots.

I tend to agree! Not impressed with the anchoring power of a 220 grain hpbt at 1000 fps . At 100 yards it's 950 fps about like a .45 pistol off the muzzle . Some people sware by them on hogs