223 Sabot in 300BLK Anyone tried it?

[rjacobs]

The 110g Barnes black tips(designed for the 300 blackout) will expand down to around 1800fps according to Barnes.

I dont have a ballistics calculator to see what they would be doing out at say 200-300 yards to see if they would still reliably expand.

I have not heard to good of things of the VMax since its designed to fragment pretty good, but needs some speed to do it.

I think there will be some more bullets coming out geared towards the 300blk that will expand at much lower velocities. As of right now, we can only work with what we have, which aint much.

[rbthntr64]

I reckon a long/sleek, higher BC 80grain 300 ballistic-tip doing 2700fps would trump the 223.

A concerted effort by the members here could possibly convince Hornady, or possibly Sierra to do a small run of a specific bullet. If there is a big enough commitment, they would probably entertain the idea. I used to work at Sierra and saw this happen a couple times during my employment there for the US Palma Team. Small runs used to be 50-100k.

[300Blk]

The 110g Barnes black tips(designed for the 300 blackout) will expand down to around 1800fps according to Barnes.

I dont have a ballistics calculator to see what they would be doing out at say 200-300 yards to see if they would still reliably expand.

Barnes does not say 1800, they say 1300.

[jblomenberg16]

My 110 V-max load is leaving the muzzle around 2350FPS from a 16" bbl. Using Point Blank's software, it drops below 1800FPS at just past 200yds. I would guess the 110 Barnes to be pretty close as well.

Punchline is that the 110's may expand at 1800FPS, but that means they are probably going to be most effective inside of 200yds.

[rjacobs]

My 110 V-max load is leaving the muzzle around 2350FPS from a 16" bbl. Using Point Blank's software, it drops below 1800FPS at just past 200yds. I would guess the 110 Barnes to be pretty close as well.

Punchline is that the 110's may expand at 1800FPS, but that means they are probably going to be most effective inside of 200yds.

I have been doing tons of search's on the 110g barnes today trying to find a load for the non-black tips and I read a thread that said the black tip may actually be good down to 1500fps.

Can you see where it would drop below 1500fps?

[300Blk]

Light bullets in sabots don't make enough gas pressure for an AR. You could probably do ok with 90 grain Sierra 223 bullets though.

[Klem]

Light bullets in sabots don't make enough gas pressure for an AR. You could probably do ok with 90 grain Sierra 223 bullets though.

Yes it does. See earlier post this thread...13grains AP100 with a 55gn VMax cycles fine. No pressure signs and plenty more space in the case for work-up.

Anyone else have any actual experience using sabots?

[Klem]

The 110g Barnes black tips(designed for the 300 blackout) will expand down to around 1800fps according to Barnes.

I dont have a ballistics calculator to see what they would be doing out at say 200-300 yards to see if they would still reliably expand.

I look at the expansion petals of the black tip and see a pistol round on steroids. The wound mechanism is crush trail (not temp wound cavity and axial explosive fragmentation). I guess the engineers figure you can't make a slow projectile act like a fast one.

[300Blk]

Light bullets in sabots don't make enough gas pressure for an AR. You could probably do ok with 90 grain Sierra 223 bullets though.

Yes it does. See earlier post this thread...13grains AP100 with a 55gn VMax cycles fine. No pressure signs and plenty more space in the case for work-up.

Anyone else have any actual experience using sabots?

I am interested to see if you use a larger gas port than others:

What upper? If it was custom made, what gas system length and gas port size?
What buffer?
What action spring?
What cyclic rate? If you don't know - what bolt carrier velocity? If you don't know, did it lock back on an empty mag?

[Klem]

CMMG 16" upper with factory diameter gas port.
Carbine length gas system.
C buffer with normal spring.
M16 carrier
Locks back on empty mag and ejects the spent cases the same distance as normal supersonic.

You can mimick the test on Quickload.
Use 13gns AP100 (Australian Pistol)
Use a 308 bullet with a flat base like a Sierra 220 Pro Hunter, given the sabot is a flat base. Then change the weight to 61grains (55 for the VMax and 6 for the sabot).
Seating depth at least the diameter of the calibre.

Quickload estimates a MV of 2691fps, but more importantly you are looking for a chamber pressure of at least 4500psi when the projectile passes the gas port (7inches) to cycle an AR properly with a C buffer. The chamber pressure of this scenario is 7885psi...more than enough to cycle properly. I estimate you can go as high as 15-16grains before chamber pressure at its peak exceeds 62,000psi which is the SAAMI limit of 5.56NATO. At that pressure the 55Vmax exits the barrel at 3,000fps. I have yet to confrim this but will do so in the next few days. As I said, this has to be accompanied with accuracy otherwise it is all just playing around.

How we came about this cycling benchmark was when trying to find subsonics that cycled. At 4000 it went from short-stroking (ejecting but not picking up a round) to cycling, just. 4500 is peace of mind.

Our subsonic load is 12grains AR2207 which gives 1000fps for a 220gn Sierra and a chamber pressure of 6653 at the port. Quickload estimates slightly higher velocities than the chronograph but the chronograph is more accurate. Although we haven't tried it yet I figure you could go as low as 10grains, have a MV of 900fps and still cycle fully. As you know the quietest sound comes from a projectile travelling not just below the speed of sound but at least 92fps below it (Paulson, A. 1996. Silencer History and Performance Vol 1).