subsonic .223 load

[ethan95]

subsonic .223 load? found some data 55 gr fmj and 4 gr of powder

[Unclenick]

Use Trail Boss powder for the few-grain loads to get the bulk. It may be easier to get a heavy bullet to fly sub-sonic. It depends on bore condition and friction. 4 or 5 grains of Trail Boss with the 55 cast bullet may do OK.

[Jim243]

Unclenick, just how does this work? I think of 2,400 fps to 3,400 fps when someone mentions 223, wouldn't you more likely stick the bullet in the barrel and have a squib with a subsonic 223? Seems it would just be better to just use a sound suppressor.

Jim

[Unclenick]

Supressors only act on the muzzle blast noise. They don't do anything about the supersonic crack due to the bullet breaking the sound barrier. You need to use sub-sonic loads in conjunction with a suppressor to get reduction of all the noise sources involved. You see suppressors used with supersonic rounds because just cutting muzzle blast reduces sound significantly at the shooter's end, and for military snipers it makes it difficult to tell where a shot was fired from. It just fails to prevent a missed target from realizing he's being shot at, because the supersonic bullet sounds about like a .22 rimfire going off as it passes by.

Subsonic loads fired using small quantities of fast powders, like we are discussing, will lack the supersonic crack, and, because the total gas volume generated isn't large, the muzzle blast, though not suppressed, will be a lot more like the aforementioned .22 rimfire loads than a full power .223 load.

If you can fire a jacketed pistol bullet at subsonic velocities, there is no reason you can't fire a rifle bullet at those velocities. It's just ratios of pressures and bore diameters and barrel lengths and gas volumes. Barrel friction becomes a more significant actor as loads get lower in pressure, so it sometimes takes a bit more powder than you expect. I would not try to load one down very much below the speed of sound in a rifle barrel, just because you don't want a stuck bullet. For that reason, subsonic loads are usually worked down rather than up. You take a load like IMR's recommended minimum charge of Trail Boss, which is 70% fill of the space under the bullet for jacketed rifle bullets. Measure the velocity, then work down to just below the sound barrier if it isn't there already.

[Raven Armament]

One can use a charge of TrailBoss powder to get subsonic.

The trouble is Hodgdon's 55gr data is next to useless in the subsonic role.

You need a heavy bullet to perform better than a simple rock.

68 to 77gr bullets work better. Achieve 1040fps or there abouts and you will have a better load than a .22 rimfire.

That is where the subsonic heavy bullet .223 loads shine.

This is our practice load 77gr SMK subsonic .223 Remington ammunition loaded to 1040fps. Our duty load is with nickel plated brass. The practice load will not cycle a semi-auto or full-auto, but the duty load will cycle the action suppressed.

[PA-Joe]

You can also use James Calhoons Gopher loads using 800x or Blue Dot.

[D.Nix]

I have used trail boss with 55 grain fmj. im not sure how many fps they move since i dont have a chronograph (yet). they act like a .22 rimfire, but a little louder. i was sceptical about this load at first but the wife sure likes shooting my .223 now. After the first shot i looked down the barrel to make sure the round wasent stuck.

[ethan95]

Thanks for all the suggestions looks like trail boss is the way to go

[Jim243]

Intresting, I have a Savage Mod 11 in 223 with a 20 inch bull LE sniper barrel. The only thing I use is Hornady 75 grain bullets in it. Trail Boss you say, sounds like a good project.

Thanks
Jim

[44 AMP]

Just remember what you are dealing with. A .22 bullet at less than 1100fps (subsonic) doesn't pack a lot of wallop. The .25 acp is a 50gr @850fps, and we all know the power of that one.

A very specialized load, for certain applications, if it shoots well. Trail Boss is probably the best powder, allowing more bulk in the case, something fast pistol powders lack.

Using just a few grains of pistol powder will get the same results, for speeds, but leaves a huge amount of room, even in the .223 case. Some kind of filler ought to be used, for best results.

Don't expect a subsonic .223 load to cycle a gas operated action, unless you have one that is adjustable, and you can dial it up to suit the ammo. Can't think of any of those, off the top of my head, though.