Used to have TC Contender with a 10" barrel and wondering is info is out there on how it performs from a 16" tube.

About 38 fps per inch of barrel, Sierra SSP 130 gr. H4895 29.4 gr. link Had one, but i dont even remember the barrel length now. Never run it over the timers.

SAAMI has this listed for rifles.

Interesting question. Mine is also a 10 inch Contender but maybe someone with an unlimited gun can chime in. With a longer barrel you may be able to achieve some increase in velocity but of course the powder capacity is limited. For the record mine shot 140's at 1750fps but I wasn't trying to make them go any faster than what was needed to knock down rams.