Can't help ya with the 223 fluted Ultra, mine is a 22-250, but very few folks get the 1:9 or 1:12" twist .223 barrels to shoot anything heavier than 60grs, with the 40-55gr bullets shooting the best. A few 1:9" twist barrels will shoot 68-70gr bullets with the right loads, but good reports on those weight bullets are few and far between.
Lock time is the same as any other H&R, not as fast as a bolt gun, but it doesn't seem to be a detriment as good shooters can make them perform very well. The transfer bar system will cause a new shooter some issues if they don't follow thru with the trigger pull, read the Handi Basics 101 sticky for more on shooting an H&R.
The Choate Varmint forend is idea for bipod shooting, most find it to work very well, mine still shoots better rested under the hinge, but I think it's the exception, or many of those that say it shoots real good from a bipod just aren't as discriminating as I am.
Tim
