I used Hodgdon's data for .223 subsonic loads using TiteGroup. I used a Berger 52gr bullet instead though. I was impressed with the accuracy in the 1:9 barrel (all holes touching except for an occasional flyer). I only had time to shoot about 20 rounds at 50 yards, but will be going back to the range with the remaining 30 and taking notes on accuracy and velocity. I will also remember to take the chronograph. I believe they will be about 1150-1200fps. The bullets were free, the powder is for cast .357 loads (and will last a long time), so I figured why not. I may end up attempting to use them on raccoon and rabbit later this season instead of the LR just for something different. Even if I had to purchase bullets, this could make a very economical sub 100 yard plinking round with pulled 55gr bulk bullets.