Originally Posted by
petroid
The .243 WSSM IS technically legal in a HANDGUN but not a rifle. The rules for rifles give a minimum caliber of .357 and min and max case length of 1.16"-1.8". This allows the shortened 35 Rem and 358 Win in addition to the wildcat 358 WSSM which is a 25 WSSM necked up. In a handgun the case length restrictions is only a minimum of 1.16" and the minimum caliber is .243 and 4" barrel which allows basically any contender chambered in a rifle cartridge of .243 caliber or larger, including .243 Win, .308, 30-30, 35 Rem, the list goes on. You could technically build an AR-10 pistol in .308 if you wanted. I actually built a 300 AAC Blackout AR15 Pistol for this reason, along with the fact that I can put a <16" barrel on it without an SBR tax stamp.
Unfortunately, the OP is too young to carry a handgun by himself. However, if he was hunting with an adult, he could use one.