.223 Subsonic

[BattleChimp Potemkin]

Hey Gang!

I have been loading my .223 subsonic stuff for a while now (usually 3.1gr Titegroup, nice, clean, consistent). I love it! More accurate than a .22 conversion kit (55gr. Stabilizes well), I can cover a 5 shot group at 50 yards with a quarter if I do my part.

My question is: If I wanted to use a lighter, oh, lets say, 35-45gr V-max on top instead of a reversed 55gr FMJBT, would the velocity still be about the 1000fps I am getting now? I heard that if charge is the same, but lighter bullet, the velocity will be the same but pressure lower (yeah, yeah, thats me huffing from the Lee book). I think that a lighter bullet like the 35gr. Vmax would maybe lose a little velocity perhaps?

I am also considering molycoating them (or getting them already moly coated) to keep them from lodging in the barrel.

Also, in my 1/9" AR, would these stabilize? The 55gr. do, but I am concerned about losing a little accuracy because these would have the same velocity as the .22LR and weight as well. My .22 conversion kit stinks in accuracy (for my squirrel needs) and would like to phase it out for these rounds. I know this is a situation of "go and get some to try it" but wanted to know if anyone else has tried this yet.

Last question, I swear! The lighter V-maxes: Would anyone care to speculate the velocity at which these puppies begin to fragment/expand? I would like them to begin at least expansion at 1000fps for heavier critters at shorter ranges (like groundhogs and the ilk). I have taken a bunch of rabit so far with the 55grainers but would be interested in a lighter bullet to take the range out to maybe 75 yards or so.

What do you think?

The Chimp!

 

[AgentAdam]

The 69-77grain tumble and fragment better at slower speeds. They where designed for 10" short barreled m4 carbines. Im sure the lighter bullets would stabilize fine at that distance, maybe even over spin them but that would give u better expansion.

 

[ants]

Chimp, with 3.1 grains Titegroup does your AR actually cycle the bolt carrier? I've never seen an AR cycle with such little gas. Or do you pull the bolt manually?

 

[CBS220]

Thread hijack- whats the word on that Winchester ammo for training?

You use a different bolt for it that IIRC runs on blow-back principles. Perhaps something like that is available commercially?

 

[BattleChimp Potemkin]

Ants: Its a manual repeater with those loads, which I dont mind. Its like having my old Remington 7615 back .

Adam: Not sure about that. Arfcom guys say the exact reverse of that. The 75gr Mk262 was designed for improved lethality in all 1/7" rifles, not just the M4s. Also, spin doesnt help with expansion (potentially fragmentation, not expansion).

 

[jmorris]

The 69-77grain tumble and fragment better at slower speeds. They where designed for 10" short barreled m4 carbines. Im sure the lighter bullets would stabilize fine at that distance, maybe even over spin them but that would give u better expansion.

If a bullet won’t come apart from the centrifugal force of 3000+ fps and 1-7 through 1-9 twist rates you shouldn’t count on it expanding at all when it’s only moving 1000 fps.

 

[BattleChimp Potemkin]

The original question is the 35gr Vmaxes potentially expanding at 1000 fps, not super heavy rounds that REQUIRE velocity to do anything.

 

[jmorris]

If you are looking for something that might have a chance to deform at such low speeds look for bullets that must be shot from 1-14 twist barrels. I remember there was a Speer bullet that would disintegrate out of 1-9 barrels as it was designed for slower twist barrels. If the bullet you have can be used for full power loads along with fast twist barrels, its construction will in turn limit any chance of expansion at low speeds.