.223 subsonic

[tackb]

I was using a 180g round nose and unique powder , I've got some trailboss but I've yet to try it ?

[phaedra1106]

It's a nice powder for subsonic loads but a bugger to meter in some dispensers.

Do you know what OAL you used?, placing the round nose 20thou" off the lands gave me an OAL of 2.576" in my Steyr.

[Mattnall]

Looking forward to hearing all you're thoughts

You want to take a 223 cartridge and reduce it's performance to that of a heavy 22LR round for many times the cost per bang.
It might be better to get a 22LR and use that instead, unless there is some reason why it has to be 223, but since you said it's to reduce costs and only for plinking then the rimfire seems to have all you need.

What rifle are you intending to use them in?

Using 60gn 22LR sub-sonic rounds out of a 1:8 AR barrel with conversion kit, I've had some excellent accuracy and the rabbits don't know what's hit them.
Per 100 they were cheaper than a box of 100 55gn Sierra gamekings before adding powder, primers, etc.
These bullets don't stabilise very well in my 10/22 but then the twist is all wrong.
The 40gn subs are even cheaper.

[dodgyrog]

I was grouping under 2" at 100m without too much trouble with my 308 subsonic load

What bullets are you using?, I ended up with some 162gr lead round nose from Dodgyrog to try as the Hornady A-Max and Nosler CC 168s weren't stable and I had a few keyhole at 100m. I was using 8gr of Titegroup but found 10gr of Trail Boss better.

I use 25gr of Accurate 5744 (now Lovex D060) to get 2000fps - not quite subsonic though!!!