Out of interest, what were the reasons for refusal on the mods?Not really, I applied for X2 .22RF, X2 .38/357, .44, .223, S1 shotgun and mods for all of them. Was granted everything albeit the .223 and a mod for my .44 for some insane reason.
As long as you have good reason for each gun/calibre then there should be no limit on the number you initially apply for.