[HTR]

After about 12 different combinations, I finally have arrived at a subsonic load that is consistent, accurate, and uses a pretty inexpensive powder. I think Andy is also working on this load using a 135 grain bullet, so his will be slightly different.

Here is the load:

- SSA brass

- 7.2 grains of Trail Boss

- 130 grain Combined Technology ballistic Silvertip

- Wolf Primer

- COAL of 2.29"

This load has been under development for about two months. I am also still working on Unique, but this one shows more promise right out of the gate. After firing the strings of 7.5 and 7.2 grains, I saw that the 7.2 was once again very consistently subsonic. The chrono showed 1001 FPS from my 12.5" and 1047 FPS from my 16" CA barrels.

After firing a few round of the 7.2, I then shot a 3 shot group at a steel plate at 100 yards. I held the D-740 Mil-Dot reticle at the 12 o'clock position as if firing at a clock face, and the first bullet struck nearly in the center. I then fired two more at this POA and they hit about 1.75" apart.

Not bad......

More on this later. I will load about 100 of these and shoot them for more consistency testing.

I will also try this load with the Sierra 130 grain Game King, to see if I can get any expansion.

Don't even bother with cycling. They won't. I used an adjustable gas block turned all the way off, for ultimate in sound reduction, and these were stupid-quiet. Right up there with my Ruger integrally suppressed 44/77.

 

[zoomie]

What was the temp/elevation? Sea level? I really don't have a dog in the fight, but it's interesting to learn.

 

[marinesg1012]

Thanks for the update HTR, what about those hawks 150's..... thinking about putting an order in want to go 50/50 again?

 

[RoAus]

That's great news HTR! I really appreciate those of you who are working on the subsonic 68 loads. I'm trying to learn as much as I can and I'm almost to the point of helping out, if I can ever decide on which of the last few pieces of reloading equipment I want to foot the bill for.

Just curious HTR have you tried any of these loads that Constructor worked up? I believe I found these on AR15 some time ago and save them to a word document for future reference.

Subsonic Loads

Loader: constructor
Powder: 11.6gr RE7.
Bullet: 130gr Sierra SBT
Brass: SSA small primer
Primer: n/a
Crimp: none.
OAL: 2.26".
Gun: 16" Model 1 1:10 twist, carbine gas system
Chrony Data (@ 10'): 11.7gr =1200fps
Note: Cycles the action!

Loader: constructor
Powder: 16.1gr 748.
Bullet: 130gr Sierra SBT
Brass: SSA small primer
Primer: n/a
Crimp: none.
OAL: 2.26".
Gun: 16" Model 1 1:10 twist, carbine gas system
Chrony Data (@ 10'): 16.3gr=1250fps
Note: Cycles the action!

Loader: constructor
Powder: 20gr RE19
Bullet: 130gr Sierra SBT
Brass: SSA small primer
Primer: n/a
Crimp: none.
OAL: 2.26".
Gun: 16" Model 1 1:10 twist, carbine gas system
Chrony Data (@ 10'): RE19 20gr=1040fps
Note: Cycles the action!

Also were you using a standard spring and carbine buffer with this last test?

 

[rob_s]

Is there a potential that these rounds will still expand in soft tissue? Have you shot any soft targets with them yet?

I like where you're headed with the heavy projectile as I think it's always the answer when talking about subsonic rounds. Makes a lot of sense that if the velocity is fixed, the way to greater kinetic energy is a heavier projectile.

 

[HTR]

I tinkered with all sorts of powder for a while. the RE7 load had me interested because I thought I might be able to cycle the action, but I never was able to get reliable cycling. That will depend upon the bullet as much as anything else.

First, it will likely have to be a full-sized, full .277 caliber bullet, like the SMK. Some of these are .276. Second, I think Constructor was using a pistol gas gun.

After getting way too many supersonic cracks with the RE 7 loads, I then went back to the basic principles. Trail Boss and Unique. These are the powders that are the Gold-standard for the .308.

I doubt that we will get much expansion of any of these bullets. If we can get the 150 grain Hawks to stabilize, then ou might get just a little. I like the ballistic silvertip a lot because it is an accurate bullet, and with that sharp tip, it might just break off after penetrating.

 

[marinesg1012]

HTR check you pm's....

 

[QuicksilverJPR]

That's great news HTR! I really appreciate those of you who are working on the subsonic 68 loads. I'm trying to learn as much as I can and I'm almost to the point of helping out, if I can ever decide on which of the last few pieces of reloading equipment I want to foot the bill for.

Just curious HTR have you tried any of these loads that Constructor worked up? I believe I found these on AR15 some time ago and save them to a word document for future reference.

Subsonic Loads

Loader: constructor
Powder: 11.6gr RE7.
Bullet: 130gr Sierra SBT
Brass: SSA small primer
Primer: n/a
Crimp: none.
OAL: 2.26".
Gun: 16" Model 1 1:10 twist, carbine gas system
Chrony Data (@ 10'): 11.7gr =1200fps
Note: Cycles the action!

Loader: constructor
Powder: 16.1gr 748.
Bullet: 130gr Sierra SBT
Brass: SSA small primer
Primer: n/a
Crimp: none.
OAL: 2.26".
Gun: 16" Model 1 1:10 twist, carbine gas system
Chrony Data (@ 10'): 16.3gr=1250fps
Note: Cycles the action!

Loader: constructor
Powder: 20gr RE19
Bullet: 130gr Sierra SBT
Brass: SSA small primer
Primer: n/a
Crimp: none.
OAL: 2.26".
Gun: 16" Model 1 1:10 twist, carbine gas system
Chrony Data (@ 10'): RE19 20gr=1040fps
Note: Cycles the action!

Also were you using a standard spring and carbine buffer with this last test?

Only the last load there would be sub-sonic for me. My threshold is typically around 1116 fps where I live...

 

[Drof]

If your coal is 2.30" in pri mags what would be the longest bullet length you could use and have a decent chance of it still performing properly? For subsonics the heavier the better, so does anyone know if there are nay 150grs that will work? I email hawk to ask there bullet lenght on there 150gr RN and ask if they made one with a thin enough jacket that it would work at sub-s vel? No response so far. Guess there busy making bullets! I'm going to start with trail boss and the 135gr SMK like Andy so when my AAC gets here at least I'll have something to use, although I hope to find sbs rounds that cycle the action reliably. Looks like I need to order some of Constructor's components.

 

[marinesg1012]

Drof, I have also been in contact with Hawks and will be ordering some 140 grain (we decided on the 140's becuase we arent 100 percent sure the 150's will stabilize in a 1-11 or 1-12 barrel) bullets that Hawks has designed for the 6.8 subsonic.... it has an round exposed tip with a hollow point, Hawks says it should open a little, they cant say exatly how much... HTR and I are going to split the 4 box min order for these bullets and report back on how they do.

 

[RoAus]

marinesg1012, Are those Hawks boattails or flat ends?

Never mind found it on Hawks site, no boattails.

 

[marinesg1012]

they are flat based.

Hawks was closed yesterday so my order will go in on monday, they said they will be doing a run of .277 caliber bullets in about 2.5 weeks so we should get them in less then a month....

 

[RoAus]

The ones your ordering are not special order are they? I see them listed, so you shouldn't have to order a 4 box min. should you?

 

[marinesg1012]

The ones I am ordering I think are a custom run, I told him I wanted them made just for subsonic loads so I think the jacket is going to be thinner and the lea softer then normal also they are going to give it a hollow point.
here is how Hwaks described them to me

Hi Adam; We have made .277's that are a true round nose shape ahd added a nice looking hollow point for sub-sonic use. They are not listed on the website but we double anneal the jackets and use pure lead cores. With all that they are the best at sub-sonic in that caliber however they won't look like the larger caliber bullets we make as the larger the diameter the easier it is to get expansion.

He told me he needed a 4 box min to make them up, and that is only 200 bullets so after HTR and I split them that isnt a ton of them left for testing and killing, especially how HTR has such a target rich environment around him

I think the other 277 bullets are designed to be pushed out of a 270 so are made a little tougher... Since I am not home I hesitate to do a group buy but if these work out well for HTR and I then maybe The next order I will post up and we can do a group buy for those interested?

 

[RoAus]

That sounds real good to me if they work out you can surely count me in on the next order...if I can wait that long!

 

[marinesg1012]

SOunds good, I am sure HTR will let us know how his current sub load and these new ones when we get them work on game... hopefully i can load some up befoe I head down there in july (hopefully I can get down there) and shoot some stuff with them as well

HTR gets to kill more game in a month then most of us do in a year so I trust his opinion on bullet performance on pigs and deer, plus all the varmints he gets to kill off of his feeders.

 

[Andy]

If you guy's haven't already ordered the projectiles, I'd love to get in on your order for a box or two. Please let me know if I can sneak in.

 

[marinesg1012]

After I have tested them I will try to do larger purchase next time, it is hard as I am overseas for the majority of the time.

However if you guys are interested in the subsonic bullets then after we make sure they stabilize and everything I will try to put an order together....

 

[RoAus]

Andy,
HTR & marinesg1012 are placing a special order together to test out this bullet to see if it's usable. Which I bet it will be and I'm sure HTR we let us know his findings and not to exclude marinesg1012 but who knows where he's at in the sandbox or when he'll be through playing in the sand to come home for testing
Now what does concern me is if Hawk only does these special runs of bullets once or twice a year, then I would really like to jump on an order or get one up myself.

EDIT: Well marinesg1012 bet me to it...

 

[marinesg1012]

Talking to Hawks they said they are very busy, now they did say they were running .277 bullets in a few weeks so we should be able to get into that order, I am guessing if they werent doing that run we would be waiting a few months.

You are correct HTR will get the bullets to test before I do, I am acctually hoping he can get a load worked up before I get home so I dont have to do all the work

I am sure these bullets will work well compared to other .277 caliber sub loads.. Hawks said that since the bullet isnt very large we wont see the same expansion as compared to the larger diamiter bullets but I am convinced for what we want to do with it they will do the job... I personally only want them to shoot feral cats without the nieghbors coming over to see whats going on and to kill stuff at HTR's place