Subsonic Loads for 223

[tsmysak1]

Hi all,

Looking for information on subsonic loads for the 223. I would like to find a load for both the 55 FMJ and the 68 HPBT for about 1050 fps. This is to go through a can.

Twist is 1:7 and barrel length in 16".

I once saw a Thompson TC detonate with a reduced load of blue dot in a 17 fireball, and I am aware of other failures. Obviously I want to avoid at all cost. I would really like to know what some of the manufacturers are doing for these rounds (e.g. TTI). I realize these do not cycle a semi auto. I do not care about that. I just want a dead quiet round that can be used interchangeably in a setup that is ready to go with 223 standard ammo.

I see hodgden's site has listed a 3.1 grain of Titegroup load with a 55 FMJ. Has anyone tried this one?

 

[Disposable Heart]

I have done the Titegroup load out of a 16" 1/9 AR. They are VERY accurate and has harvested many a midnight raccoon invader at night.

25 yards looked like a dime group with iron sights, they hit same POA as M193 (what my sights were calibrated for, I wanted to see if they could be used as a low recoil and low sound 25M "zeroing" load).

They are exceptionally quiet, slightly louder than a CB cap. I am unsure, however, of their long range accuracy. I fired a few at 100 yards to see if they keyholed, I am remissed for not properly setting up an accuracy test, but they hit the target, no keyholes but at a lower POI.

 

[tsmysak1]

Will the heavier bullets keyhole in the 1:7 twist? i.e 68 grain?

 

[sloughfoot]

The 68/69 should be stable with the 1:7 twist. Stable as in ice pick. That should be the terminal ballistics of any jacketed 223 round impacting at low velocity.

Remember, the 223 is effective only because the bullet has a chance to tumble when driven at high velocity.

Of course since you are contemplating a rabbit hunting load instead of an anti-personnel load, many rabbits will fall with no noise to disturb the neighbors.

IMO, the soft lead 22LR is more effective with a can.

But this doesn't really answer your question does it?

You might find yourself drilling out the primer hole like with the 30 caliber reduced loads with pistol powders and lead bullets.

I hope someone comes on with a reduced load for this caliber, but I think a lead bullet would be better than jacketed if for no other reason than it would obturate better than a jacketed bullet.

 

[Disposable Heart]

Not sure about the 1/7 and 68/69. Accurate Powder has recipes for those weights! Because the bullet is not traveling as fast and it is heavy for the speed, you may want to make a small lot then fire them for keyholing, do what will work in YOUR gun, as opposed to "it should work". Just in case, bring a cleaning rod you dont care about and a hammer to potentially pound out any squibs.

Never tried a lead bullet for my subsonics, then again, the recipe that Hodgdon called for was a jacketed one. I also never drilled out my primer flashhole, never had a primer back out.

One note of advice: I got horrible variations in velocity when I just fired them. I suggest (and it worked for me, made the variations down to nothing) pointing the rifle slightly upwards, shake it (to get the powder in the cartridge towards the primer). It helped minimize the velocity variations.

 

[tsmysak1]

Range Report

Ok, this is through a piston gun with a YHM 5.56 can. 1:7 twist - Standard loads are not harsh on the ears, but you would not want to shoot a lot of rounds with some sort of ear plugs. Very sharp sonic wave.

I first tried 3.1 grains Titegroup behind a 55 grain FMJ. Perfect ignition, groups well at 25 yards. Sounds about like a 22 mag unsilenced. Very pleasant with the suppressor, but not real quiet. You can hear the bullet hit, but seemed to be a lot of sonic noise.

I was leary about these loads, so I called Hodgdon. They said there wasn't much demand for the loads, so they only developed the ones on their site. The boss doesn't want anymore testing. The person said that Titegroup is very easily ignited and therefore does not suffer from all the empty space in the case. He did not think there was any danger with the reduced load.

Next trip is with a chrono and loads at 2.8, 2.9, 3.0, and 3.1 grains...This is a 11 cent round...What does a sub 22 cost?

 

[tsmysak1]

Ok, posting here for the record. I could find very little info on the subject.

I was using military cases, which I think bumped up the speed due to the lower case volume. The 3.1 grain load of Titegroup was over 1100 fps. I got all the way down to 2.8 grains before the load dropped to subsonic. Chrono was working poorly and I got only one reading at 2.9 grains at 1080 fps. These loads are going to have a wide standard deviation. When you are on the borderline, some go super, some don't.

When it did drop to subsonic, the sound disappeared. I could hear the bullet clearly hit the target out 75 yards which was very cool. The can suppressed almost everything. It is very deceptive. Something that doesn't make sound can't be powerful right?

 

[Disposable Heart]

Now you have the ULTIMATE Coyote or Varmit set up!

 

[tsmysak1]

Now you have the ULTIMATE Coyote or Varmit set up!

Yeah.... but, not something I would want to argue with the pesky DNR about..

Ok, so we messed with this all weekend. We took the 55 grain load at 1050 fps and did some penetrating tests. We lost every bullet after going through 4 inches of wood (it was light wood, like pine) at 30 yards. It went through galvanized plate (1/16"). It went through bottles of water and the wood backstop. I would have thought that the low velocity would indicate that it would have no penetration.

I ran the ballistics and it shows that that subsonically the bullet does not shed energy as fast as it does supersonically. It makes up a little for starting out with 1/7th the muzzle energy.

Groups were very good, although Std Dev of the velocity was large. We stepped up to a 68 Grain HPBT match at about 1000 fps. It grouped amazing at 50 yards, will try it at 100 soon. Shoots like a rainbow. In the right light, you can actually see the bullet go through the hole in the target (in the scope) --- that's slow!! but the 68's had a tendency to be much more stable... - and almost completely silent.

 

[bm9mm]

sub sonic

I purchased some online a while back and It was aweful it tumbled out of the barrel and blew up in my suppressor. I can't remember the brand but becareful.

 

[tsmysak1]

We inspected all the shots first without the suppressor. There was no key-holing so we went ahead. I would suspect that it would show up within 50 to 100 yards, if the bullet was unstable.

I really don't have a slow twist rifle to try it out in. I imagine that a 1:12 would keyhole the 68 grain.

Can you give a few more details about the load you bought?

I have been thinking that a reduced capacity case for 223 could be made on a lathe out of a piece of brass bar stock and it would eliminate all the space (and variability)...