Currently shooting a rhino .670 and nitro H518 4/5/7 blend out of a sx3. I have too many H518 to justify going to another shell and would like suggestions on which choke to move to next. Been shooting this rhino for several years and am getting around 255 in 10" @40 yards. It's not the 280+ that Nitro is advertising with that choke so I'm hoping a choke change could get me a little higher numbers.