A sling on most rifles does more for you than just a carry strap. Once learned, the Hasty Sling aids accuracy.
But, pumps are very hard to work once in the Hasty Sling mode. One small downside.
Uncle Mike's makes adapters for most pumps, probably there's one for the 1300.
On these I like a cobra style sling with the wide end towards the butt since I favor African carry.
On a GP shotgun, sling capability is nigh mandatory. I keep the sling off in the house, CQB needs snag proof stuff.