Rabbit magnums

Not sure what a smooth twist barrel in .22 is, but my Benji M-Rod would get like 4 or 5 inch groups at 30yrds with 27grn Rabbit Magnums II. 
The JSB Monsters in 25.39grn did a 2-3inch group.
The Enjin 28.5 did a decent 1-2inch group. But would only single feed in a M-Rod magazine. 
Maybe I have to take them out further than 30yrds? If I get a chance I will try 40-50yrds Monday or Tuesday. 
 
"1kshooter"thanks for the info NorthLand43, I am using the JSB 18.13 grain as my dedicated pellet as it seams to hit the hardest and is very accurate out of my Indy .22 I have tried close range 20 yards with some Gamo TS22 22 grain and it shot very well also, have to try them at longer range next time!
Jonathan
Glad to be of help.
I use the JSB 18.13 as my go to pellet too. If I want a little more energy or less wind effect at distance, I will use the H&N 21.grn.