Gunsmithing 6x47 Reamer Question

[BLopina]

I'm going to start my first 6x47 build and I got some good reamer advice from an experienced gunsmith but I still have one question...

What freebore puts the 105 Hybrid just in front of the neck shoulder junction as to avoid potential donuts from necking down? Ultimately I want to shoot a 110 sierra with a 50-80 thou jump but there isn't a lot of info on this bullet yet. I figure if I get some info on the Berger Hybrid I can get a rough idea of where I need to be with the freebore. Right now my initial thought is around .120 freebore. I know the 110 has a very small bearing surface but with that freebore I should be able to jump it .050 and still be ahead of the neck shoulder junction. And if they don't shoot I'm hoping that will still work with the hybrid.

I searched and didn't find any specific info on this topic. Thanks for any replies!

 

[Citius7]

We shoot a 115 JLK. Similar in bearing surface to the 110 if I 'member. We run a 120 freebore. But we're jumping only .020.

 

[BLopina]

We shoot a 115 JLK. Similar in bearing surface to the 110 if I 'member. We run a 120 freebore. But we're jumping only .020.

Where does that put the boat tail bearing surface junction in the neck?

with a .050 jump are they in the donut area?

 

[MTyotehunter]

If you were dedicated to running dtacs around .020 jump(where most run them) you be looking for .170ish FB. also if you don't want to turn necks get at least a .273 . the .272 is to tight, I ended up turning necks and running dtacs from a .093fb but I'd love to run it out to .170

 

[steve123]

I've got a .208 freebore reamer. Back before I knew any better this was what I ended up with from the GS who ordered it that way.

Originally I settled on 115 DTACS, they shot great and I was able to reach the lands while still running from a AI mag. Probably 2/3's of the bullet's bearing surface in the neck.

Then when they dried up during the shortage I started using the 105 hybrids which have a huge jump but they shoot just as good if not better. No doubt in my mind that the hybrids are the jump king.