sea hornet Rhino

Yeah, unfortunately different manufacturers use different ways to designate their guns and sometimes the numbers are misleading. For example, the most popular Sea Hornet is the 42 model, which actually measures 45 inches from muzzel to butt. However the standard shaft is 42 inches, and the barrel ahead of the trigger is about 38 inches. If you bought that gun from a dealer and you think is too large for your needs, you can ask for it to be exchanged for a shorter one. Or you can just saw off a few inches from the barrel, although then you will have to reseal the wood and also probably shorten the rubber bands and buy a shorter shaft. Dive Sports sells the Rhinos and they are your best source for advice. You can find their 800 number in this link:
http://www.divesports.com/IndexPages_Brand/SFS_sub_rhinoclassic.htm
Good luck.

i think they measure length of gun from muzzle to trigger mech, the bit sticking out of the back is pretty much only for loading, and maybe asthetics