Gents,

I'm in the process of working up my hunting load and I'm having trouble finding the correct starting charge for this projectile.  My accuracy load is a 168gr SMK over 43.5 gr of 4064.  For that reason, i'd like to use 4064 for this as well.  I have talked to Hogdgon and Hornady with no luck.

Below is the information:
Caliber: .308 winchester

Projectile: Hornady GMX, 165 gr.
Case length: 2.012
COAL: 2.800
Primer: CCI 200 Large Rifle
Powder: IMR 4064


The Barnes TTSX is also an all copper projectile and I was told the following from Barnes:
Projectile: 168gr ttsx
Powder: IMR 4064
min - 42 gr.
max - 46 gr.

Should I use the same starting point for the GMX as i am for the TTSX?

I'm curious what you mean by having no luck with Hodgdon and Hornady? Hornady advertises the GMX as being compatible with conventional reloading data, and Hodgdon does have data for IMR 4064 with a 165 grain bullet.

I called Hornady and they didn't have any testing information with 4064 and suggested i call Hodgdon.  Hodgdon said they also did not have any testing data for that projectile and 4064 but suggested using the starting point of another slower burning powder (such as 4895).  He did mention that the grooves in the projectiles will have an impact on pressure...

Hodgdon doesn't have data for that particular bullet, but they do for the Hornady 165 gr. SP bullet. So it just comes down to whether Hornady is serious about the GMX being "compatible with conventional reloading data" (that's kind of a big deal because that's one of it's selling points, and different from the Barnes bullets which do use different data than conventional bullets). If so, then the Hodgdon data should be correct for the GMX as well. Catch 22 I guess, but I'd be comfortable with the Hodgdon data.