western saddle fitting question

Yesterday I rode Sonny in a western to see what type of saddle I should get. The saddle I put on was has a full quarter horse bar or a wide bar (whatever you want to call it).
I placed it on Sonny with no pad and I could get 4 fingers inbetween his withers and the saddle (don't know the correct name of it in a western saddle). Since I thought it looked like it fit, I put a saddle pad, and then saddled him up. It seemed to fit, but the one thing I noticed was that it did slip a bit. Not on the withers...but on the back.

Is it normal for a western saddle to be fairly loose in the back? No I didn't use a back sintch for the saddle didn't come with one and I don't know how Sonny would react to it.

When you cinched it up did the back end of the saddle rise up a bit? If so, its because the tree has too much slope in it and its is round on his back causing the rear end to flip up. The gullet may be too wide too. It may sit the proper four fingers above but if the gullet is too wide the saddle will tip down in front, creating a loose back and adding excess stress on the horses withers.

Also the farther forward the front rigging the more apt the saddle is to slide back. I kind of prefer center-fire rigging. Center-fire rigged saddles must have the right amount of curve in the saddle tree for your horses back, if not, your saddle will rock back and forth and damage your horses spine. 7/8th is by far my preferred over 3/4 rigging. I feel like 3/4 actually pulls the rear end up when you cinch it.

the back end did not appear to rise up like one western saddle I tried on.
What I did to see if the gullet was about right was to put the saddle on bareback, and put it in the right place where it should be...then I putmy hands where his withers are and felt how tight it was across there. For english I know you want it where the gullet sits flat on the withers but not tight, so that's how I had it...or thought I had it.

It didn't slip backwards or forwards...but it just moved side to side fairly easy...mainly it did that if I made it move or if I was dismounting (not mounting thought for some reason).

I'll try to get some pictures if I go up and ride today...hopefully I'll be able to

I'm not sure, my saddle sits just fine on Solomons back but my moms saddle's rear end kind of moves around a little while mounting or dismounting.

Back cinches are nice but wont help eliminate that really because you are supposed to keep the back cinch loose unless your cutting or roping or something like that.

Here are some pictures of me in the western saddle that I put on Sonny the other day







I know you can't see too much of how the saddle fits....but it might, who knows[/img]

It looks like your stirrups are too short but I have no idea why the rear end is slipping around. It seems to fit him fine, although I couldn't really tell from the pictures.