Im using H110 in my midlength with no issues. Im running a standard .223 carbine spring and buffer with a MagPul UBR stock. I also shoot some 300 gr FPRN gas checked cast bullets I got in Martinsville before they jacked their prices up. They shoot really well. I use those for the new shooters who want to shoot my .458 and for just shooting at the range. Remington 300 gr. JHPs shoot really well for a cheap bulk bullet. I will do some looking and see how much "extra" brass I have. I know of the 50 that are primed and sized... those were part of the last 250 new pieces I latched on to. I will PM you with quantities and pricing when I go through the rest of my boxes.