bikemutt
Member
I recently installed a new Odin Works 6.5 Grendel barrel in an AR15 upper receiver. After break in using Hornady 123 gr AMAX factory ammo and thoroughly cleaning everything I set about measuring up for some hand loading. With a Hornady OAL gauge and 120 AMAX bullets, I measured 2.237" OAL with the bullet fully engaged with the rifling. I did this several times to check my work and confirmed I can see where the bullet clearly contacted the rifling.
The Hornady 10th edition load book recommends a COL of 2.245 for a 120 gr AMAX, 6.5 Grendel.
So, in theory, if I load this cartridge to book at COL 2.245", either the bolt won't close, or it'll perform final seating with a jump of 0". Or maybe something else I don't know about, yet.
The other side is maybe I measured something wrong, or I assembled the barrel to the upper receiver wrong. Empirically the rifle experienced a remarkable number of jams with the factory 123 AMAX rounds, stovepipes in all cases. Granted this barrel came with an adjustable gas block which I used SOP to adjust but, this isn't my first adjustable gas block rodeo. And, I was using metal 7.62x39 magazines. I mention these factors in order to paint a more complete picture of the experience.
I'm mostly concerned about the apparent shortness of the chamber if in fact that is the case. Thoughts on the matter greatly appreciated.
The Hornady 10th edition load book recommends a COL of 2.245 for a 120 gr AMAX, 6.5 Grendel.
So, in theory, if I load this cartridge to book at COL 2.245", either the bolt won't close, or it'll perform final seating with a jump of 0". Or maybe something else I don't know about, yet.
The other side is maybe I measured something wrong, or I assembled the barrel to the upper receiver wrong. Empirically the rifle experienced a remarkable number of jams with the factory 123 AMAX rounds, stovepipes in all cases. Granted this barrel came with an adjustable gas block which I used SOP to adjust but, this isn't my first adjustable gas block rodeo. And, I was using metal 7.62x39 magazines. I mention these factors in order to paint a more complete picture of the experience.
I'm mostly concerned about the apparent shortness of the chamber if in fact that is the case. Thoughts on the matter greatly appreciated.