Saddle slipping- breastplate??

[PonyGirlAsh]

Hey guys! So I've noticed that everytime I get off Eddie after a good long ride, his saddle has slipped back a good 4 inches or so, maybe more, but I'm just guessing. Could this be easily solved with a breastplate? Are some horses just more prone to this than others, or do you think it could be a fitting problem? As far as I know about it, his former trainer had this saddle fitted for him, but I don't if his saddle is the problem or not. I'm looking at breastplates, and it seems that the stretchy ones look best, but I don't have the first clue about it!!

Basically I need to know if a breastplate will solve this, and if so, which are the best kind (that I can get hold of on ebay or somewhere like that for not too much $$). Thanks!!!

[Showjumper]

If he's muscled up/changed shape since the saddle was fitted, it could now not be fitting as well as it did. My first port of call would be to get the fit checked. Unless you're riding up particularly steep hills the saddle shouldn't slip backwards, especially not that far!

[PonyGirlAsh]

Thanks showjumper! Forgot to mention, his owner uses a riser under his saddle...I look at it and see it raising the saddle completely off his back for the most part. I'm definitely not an expert on this, but do you think I could try using a beval or just a plain saddle pad and see if this helps?

[Showjumper]

If the riser is making the saddle too narrow, a thin pad might help but it does depend on the fit of the saddle to the horse :)