Quote Originally Posted by Guesty View Post
N133 is great for 50+gn bullets.
Your loads sound a little low perhaps, I use 24.5gn under a 52/53gn bullet to give 3300fps (@ 30c) from thick Lapua brass. Lower temps and more skimpy brass (with greater capacity), such as the US brands will give much lower velocities. A buddy uses a full grain more with Federal brass to give the same velocity.
I have no experience of IMI though.
N133 is a bit slow for 40gn bullets, but it should work OK until you run out of case capacity.
Packing out scope mounts works, but a neater solution is to use Burris Signature rings. They will allow you to align your scope with the bore without stressing the scope tube.
I have great results with n133 and 40 gr vmax/ blitzkings.... Mostly all I shoot now. .5" groups @100yds are the norm.

Rich