I don't know a load that will cycle a normal gun and is subsonic.
If you want to make a subsonic round, it can be done with trailboss powder.
But honestly, I don't think it is worth it. Buy a 22LR kit for semi-auto fire. If you need 1 round of subsonic and then regular ammo, they make sigle round conversions.
The Suppressor guy at my gun shop recommended Engel Balistic Research. I have not ordered any of these because I don't have my .223 can yet but as soon as I get it I plan on placing an order for the EBR ammo.
I have looked into that EBR ammo, that is the reason I wanted to try some handloads because EBR is around $30-$40 per 20 rounds. At that rate I could shoot all of one hour before I broke the bank
On a side note I did look around here and found some good handloads.
starr2233 wrote:I have looked into that EBR ammo, that is the reason I wanted to try some handloads because EBR is around $30-$40 per 20 rounds. At that rate I could shoot all of one hour before I broke the bank
Good god man.. What are you hunting where you are going through that much ammo???
I just ordered 2 boxes of EBR ammo today. If my Form 4 ever comes back I'll go out and shoot it with my M42K on my gas piston AR.
He's done a lot of work with .223 (amongst other calibers) and subsonic loads and has a fair amount of different weight bullets using Blue Dot. I've tried a few myself and they are very accurate and very quiet.