SeniorSpaz87

Ok, and what should I call it? If that ask

I usually put toy or sporting goods when shipping a rif. Anything with firearm, weapon or rifle could bring some extra attention to the package

Declare it for what it is - an airsoft replica. It's perfectly OK to send using RM/PF so listing it as something other than what it is will be MORE likely to cause problems when they scan it.

Read the Ts&Cs on the Royal mail site regarding posting restricted items (do a search for airsoft). You have to use a minimum level of service and insure it correctly too.