Your post is a bit imprecise, but I suppose you mean that you returned while carrying a shotgun and an AK47? (one carried on 47’s back and other in hands, or one weapon on 47’s back and one inside an attaché case). SMG depends on which SMG as some are one-handed.
Returning with two large weapons should not cause a crash, but carrying more than your capacity limit (shown in upper left corner of screen, such as “Gear Capacity: 11/10”) has been reported by other players as possibly causing a crash.
Try Diana47’s advice in this post.
Best regards.