The 6UM

[khuber84]

What do you like for min neck clearance hunting? That's part of where I screwed up on my one custom reamer order. Shouldn't have listened to the bench guys!

4-5 thou for cartridges, under 60gr, 5 though for case larger. I turned some Norma improved for 6thou clearance, and it works great. 5 is kinda the gold standard. Anything under 4 and it's tight getting a bullet into a fired case, and I don't like that. Tight necks are for the benchrest/F-class bois.

 

[BHenderson]

Does a 6 UM feed reliably out of any of the factory Tikka magazines?

 

[Ryan Avery]

Does a 6 UM feed reliably out of any of the factory Tikka magazines?

Yes, I use a LA Mag and the 6.5 PRC mag. No issues with either

 

[UpNorth89]

Has anyone had issues with a 7 twist yet?

 

[Sjacskson]

Any insight on when FF 40degree brass will ship???

 

[gtriple]

Can somebody please check my math on the below?
I've heard Ryan and Jake say that the 6UM kicks "like a 6.5CM". Both are with an 8lb rifle, which is my planned lightweight Tikka build. Using this website as the calculator: https://shooterscalculator.com/recoil-calculator.php

6UM: 108gr ELD-M, 66gr charge weight, 3200fps MV (18" barrel). This is about 18.1ft-lbs of recoil.

6.5CM: 143gr ELD-X, 46gr charge weight, 2850fps MV (24" barrel). About 16.1ft-lbs of recoil.

Edited for maximum charge weights. Looks much closer now.

 

[khuber84]

Standard 65cm loads are 41-42gr powder. But the 6um does have a bit more push to the shoulder than a 65cm.

 

[gtriple]

Standard 65cm loads are 41-42gr powder. But the 6um does have a bit more push to the shoulder than a 65cm.

Thank you, that gets it much closer.

 

[khuber84]

Thank you, that gets it much closer.

66gr N570 is pouring the coals with crack powder to the UM.

46gr rl26 is pouring the coals to the 65cm with crack powder. They're even closer in that comparison. Mv of a 140ish bullet with the 46gr rl26 charge would be 2850. This would be the most comparable apples to oranges data.