There are some lessons that a guy learns the hard way. I built a 6 mm Creedmoor Match rifle using an Origin action, Proof Research heavy competition SS barrel, triggertech diamond trigger sitting in a MDT ACC chassis. The gunsmith chambered it using a PT+G minimum Sammi spec match reamer and it was shooting great groups using factory Hornady 108 eld-m but when trying to extract a live round (factory or reload) from the chamber you have to pull the bolt back fairly hard to extract it. The factory rounds or my reloads aren't seated long enough to hit the lands, it's contacting 1/3 two 1/2 of the bullets side in the freebore area. It has .00025 clearance between the bullet and the freebore diameter. In testing when cycling my handloads I had a bullet stick in the chamber when trying to extract it. Since the neck area of the chamber has about .004 clearance on the factory round we figured we would try and open up the freebore by
.0005. that turned out to be a terrible decision, it went from shooting one hole groups under an 1/8" to averaging 5/8". So now I'm going to scrap that set up and I'm wondering what chamber reamer specs I should be using?
3 rounds of factory ammo before opening up freebore.
Factory ammo groups after opening up freebore
.0005. that turned out to be a terrible decision, it went from shooting one hole groups under an 1/8" to averaging 5/8". So now I'm going to scrap that set up and I'm wondering what chamber reamer specs I should be using?
3 rounds of factory ammo before opening up freebore.
Factory ammo groups after opening up freebore
