I just bought a 300 WSM.I chose a Hornady 165gr flat base bullet to work up a load for it.The COL shows to be 2.840-2.900.This bullet touches the lands @ 2.820,so I seated it @ 2.810.The deep seating of the bullet also has me reducing the powder charge.I worked up a couple of loads using IMR-4350 and Winchester WXR.I took it up to 66.5gr with the IMR-4350 before I started getting a sticky bolt and backed down to 65.0grs as my load for it.With the Win.WXR,I went up to 71.0grs and backed down to 69.0grs as my choice load.I haven't had a chance to get back to the range to chronograph my velocities yet to see what I came up with,but it seems like it's either the bullet I chose or this rifle has an awfully short throat.It does however seem to shoot quite well.

sounds like your rifle does have a short throat. YOu should be able to seat 180 gr boat tails without problems in a wsm, but If it shoots great... whats the problem?

Finally got back out to the range this morning and set up my chronograph to test my loads.The 69.0grs of Winchester WXR tested out to be the same as Reloader-22.69.0grs of each powder gave me 3023-3016fps velocities.The 65.0sgr of IMR-4350 gave me nearly the same velocities @ 3003-2989fps.All loads were using a 165gr Hornady Interlock solid base bullet.All loads seemed to group well but the 4350 loads shot 2" higher and 2" to the left of the WXR and Reloader-22 loads.I think if I could have seated the bullet out another .050,I may have been able to get a little more powder and maybe 50-100 fps more out of it,but I can live with what I got.