remington managed recoil slugs are very tame, I use them to practice with my pistol gripped maverick 88. I'm geussing your first time was with the heaviest slug or buckshot load your buddies could find for you? Anyways standard velocity 2 3/4" slugs and buckshot arent too bad either. As some suggested, start with some light target loads, like the winchester 100 rd. value packs from walmart or canadian tire, or top gun from most places that sell ammo. The maverick 88 is the same basic shotgun as the mossberg 500, and I can say to a certainty that mine has no problems cycling the cheap winchester stuff. Buy a couple boxes of standard 2 3/4" slugs and buckshot of your choice to try after you blast off the target loads. Limbsaver also makes a recoil pad for the m-4 stock that comes on your SPX, I put a slip-on limbsaver on my Benelli and couldnt believe the difference it made. I had some 3" Federal classic slugs (1 1/4 oz. @1750 fps, insane recoil) and would always flinch horribly and couldnt hit a damn thing with them, then I slapped on the recoil pad and fired 10 rounds in a row and found myself simply resting the buttpad on my shoulder and gently squeezing the trigger, feeling very little recoil.