Vihtavuori N133
This power is ideal for 50-55 grain bullets. 


Vihtavuori N133
This is an extruded stick powder, like all the VV powders we have.   It is perhaps, the best powder you can buy for 50 grain bullets?  Or maybe 55 too.  Its simply highly accurate and very high velocity as well.  Its top ranked at both those things.  It meters like most other stick powders, but the stick is not too large/long so it never got stuck for us.  So its consistent.  Of course all these loads are triple checked, hand loaded, not metered, which is why they are all so low SD.

We submit to you folks, that N133 combined with a 50 grain bullet in around ~25 grains is going to be one of the best loads for under ~300 yards you can do in an AR15.  In our Rifle N133 averages around ~.7 MOA.  Thats just fine.   
Brass
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Some pressure signs, minor, started to show in some loads.  Nothing major.  I could shoot these loads all day, and I would be comfortable.  No burs sticking up on anything, just imprints...swipes...especially in the 25 grains of SBK50
Vihtavuori N133
Good groups across many loads.  We did increments of .1 for 50 grain bullets on purpose to demonstrate that 24.9 is a very good choice using this powder in 50 grain bullets.  That is Sierra's accuracy load, we think, as well.  Look how the point of impact is the same at 24.8, 24.9 and 25.0.  That is very important if you want consistency.

Some of the Loads we tried
Load at your own risk.   Good velocities.  Very good Standard Deviation.  Really good powder for 50 grain bullets, one of the best perhaps.  3350 FPS?  That is an effective number for 300 yards and under, with a good combination of power and velocity.