Subsonic 223 for AR rifle

[daschnoz]

Here is where I am:
I already have a working sub load - 62gr SS109 bullet over 4gr of Trail Boss (I have yet to chrono and tweak it, but it's definitely sub sonic).

I would like to do 2 things:

1. Increase the bullet weight to something around 70gr.
2. Have a bullet with more of a blunt nose. (blunt nose at sub sonic speeds produces more tissue disruption than a pointed bullet)

I was thinking about buying some 70gr FMJ bullets and loading it upside down, but the 70gr bullets are expensive (or I'm just too cheap). So I'll cast my own and powder coat the boolits.

Any thoughts on this mold for subsonic loads through an AR?
http://noebulletmolds.com/NV/product...puui75q542psj6

[Boolit_Head]

I'm betting the upside down bullets of any type won't feed or be very accurate so try a few before you invest in that method. IN fact I don't think subsonic 223 would provide much tissue damage.

[Lead Fred]

I went with 300BO for subsonic, the 224s where just too weenie at distance. I have two boxes of 60gr varminters and a bag of 75gr SMKs that will sit forever now that I switched to 300BO.

[daschnoz]

I'm betting the upside down bullets of any type won't feed or be very accurate so try a few before you invest in that method. IN fact I don't think subsonic 223 would provide much tissue damage.

Accuracy can actually increase by loading backwards for sub speeds - think rocks-in-socks aerodynamics. It pushes the center of gravity forward and the bullet is less likely to tumble. Even if it does tumble and keyhole, at sub speeds, it will still hit the target pretty much where you want it to.

Feeding is going to be manual anyway - there's not enough pressure to cycle the action.

Re: Tissue damage
A pointed nose will gently pierce and push tissue out of the way. A blunt nose will shove material out of the way - ripping and tearing as it does so.

I went with 300BO for subsonic, the 224s where just too weenie at distance. I have two boxes of 60gr varminters and a bag of 75gr SMKs that will sit forever now that I switched to 300BO.

That's what 7gr of Unique, the 247gr NOE mold, and the FAL are for (they don't cycle that either).

[Tackleberry41]

I messed with subsonic 223 but never could get very good results. Used the tried and true trailboss recipes. But over a chrony, they are all over the place, 200fps variation. And Im using a jewelers scale that goes to .01 gr. I get beautiful results out of my 30 cal weapons, w often 10fps ES variation or less, and plenty of accuracy.

I cant find a concensus on drilling the flash holes larger, some swear by, some dont do it. Never have with other weapons. Didnt know if it was simply the way trailboss is or some other issue. Kind of gave up as its hard to get good accuracy with such large swings in velocity. And had several close calls where the bullet barely made it out of the barrel. I use S1000 in all moy other subsonic, might try some of that. See if it makes a difference.

The bullet it seems to use would be one of the 'hornet' ones, they have a FN HP but its only 40gr. Seems a 70 or even 80gr would work pretty good. I cant get anything over 60gr flat base to stay stable in a 1-9 barrel. The shorter FN would give more weight.

[Scharfschuetze]

I played around with squib loads in my AR15 and the M16A2 for indoor range use years ago. Looking through my records, I found the following:

Winchester 55 grain Power Point (bulk pack)
LC 72 cases
CCI 400 primer

3.5 grains Bullseye
Velocity 924 fps, Sd 44

4.7 grains Bullseye
Velocity 1370 fps, Sd 16

4.0 grains ought to put your at the threshold for supersonic velocity with a flat base soft point bullet. Both the above loads were squirrel eye accurate in the indoor 50' range. Accuracy from a bench rest would have been better, but I'm an inveterate position shooter and the loads were developed for such practice. The photos reflect groups from the prone position with sling and the M16A2 iron sights.

Here are photos from my log book:

[Scharfschuetze]

With the 55 grain GI FMJ, velocities using Bullseye powder were about 150 fps faster than with the Winchester hunting bullet.

GI 55 grain FMJ
LC 72 Cases
CCI 400 primers
3.5 grains of Bullseye
Velocity 1091, Sd 32

I apparently didn't save the targets from this load, but my notes indicate that it was almost as accurate as the Winchester civilian bullet at subsonic velocity.

Drilling the flash holes on these squib loads will prevent the cases from shrinking in their headspace measurements and will decrease your extreme spreads in velocity depending on the primer you use.

Oh and by the way, reversed FMJ bullets over Bullseye pistol powder (pulled from 45 ACP ammo on deployments) thump small animals very well and accuracy is fine at small game range. Larry Gibson called such loads his Panama loads from using them in that country.

[Jupiter7]

I've also played around with the HM2 62grn NATO mold PC no GC

i used 700x being the bulkiest powder and fast burning I had on hand, 2.5grns was used, velocity around 1070fps and not too high ES. Accuracy wasn't great but not erratic either.

ETA: finding a subsonic load that cycles the action is a fools errand

[M-Tecs]

Drilling the flash holes on these squib loads will prevent the cases from shrinking in their headspace measurements

Never played with ultra low pressure loads a bottle neck case. I never thought about the primer pressure sizing the case. I have had to drill flash holes on blank and low pressure revolver loads.

[Tackleberry41]

I will drill a few cases and see what sort of results I get. I messed w subsonic 223 a while back in an AR, but no chrony at the time. So was simply guessing at velocity, no crack was best guess. I do not remember them being very accurate. Maybe I am just asking alot, I have gotten used to tuning a load and getting cloverleaf groups out of a subsonic weapon at 50yds. But I know without consistent velocities, your chasing your tail on accuracy. Might try some of the solo 1000 I have had so much success w in other subsonic from 30-30 to 45-70.