The 6UM

[Formidilosus]

That’s a sexy sumbitch on the rifle!

1,210 yards, 8” rock.

 

[SNelson]

Good

1,210 yards, 8” rock.

Good spotter too…

 

[Ryan Avery]

Having just come from a 300 WSM to a 6 UM build, you're right on both accounts. It does everything the 300 WSM will in the field with near negligible recoil. And if you're like me, you will go broke buying parts for it too.

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If I run my 20” 300WSM with 185 Juggs against the 20” 6UM is not even close and like you stated very little recoil with the 6UM

6UM


300 WSM

 

[PathFinder]

If I run my 20” 300WSM with 185 Juggs against the 20” 6UM is not even close and like you stated very little recoil with the 6UM

6UM
View attachment 561933View attachment 561934

300 WSM

View attachment 561935View attachment 561936

Exactly, my numbers are very similar. Considering wound channels in place of bullet diameter/mass/energy leads to a much more effective setup overall. Watching impacts, even in less than ideal positions, is a big advantage.
Picture is 300 WSM w/208 ELD-M at 3.020 COAL next to a 6 UM. 6 UM has the same MER or slightly more, and better external ballistics.
My 300 WSM has been very effective, but I'm not convinced it does anything terminally that a 6mm/6.5mm doesn't, at significant cost in recoil and shootability.

 

[OneSkinnyHunter]

Thinking of rebarreling a Tikka 270wsm to 6UM…anyone see any problems I think it would be straightforward

 

[amassi]

Thinking of rebarreling a Tikka 270wsm to 6UM…anyone see any problems I think it would be straightforward

None, swap your barrel and blaze


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[Procision Arms]

Thinking of rebarreling a Tikka 270wsm to 6UM…anyone see any problems I think it would be straightforward

We’ve started an almost identical swap for a client, don’t anticipate any major issues.

It may need a different magazine, but expecting everything else to be straightforward.

 

[Ryan Avery]

I shot the 115 DTAC NR Deep Cuts that were HBN coated over the AB Doppler. It was also the first time shooting the HBN coated bullets in this rifle the velocity dropped 75 FPS which is interesting. But the BC is very consistent.

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[Tullis94]

I shot the 115 DTAC NR Deep Cuts that were HBN coated over the AB Doppler. It was also the first time shooting the HBN coated bullets in this rifle the velocity dropped 75 FPS which is interesting. But the BC is very consistent.

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I have read other places that the HBN coating reduces pressure which reduces the speed.

 

[Clarktar]

I shot the 115 DTAC NR Deep Cuts that were HBN coated over the AB Doppler. It was also the first time shooting the HBN coated bullets in this rifle the velocity dropped 75 FPS which is interesting. But the BC is very consistent.

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How do you sleep at night with that ES!!

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[Ryan Avery]

I have read other places that the HBN coating reduces pressure which reduces the speed.

I figured It would, but not that much.

Now I need to +p and HBN…. YES

 

[Ryan Avery]

How do you sleep at night with that ES!!

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I’m guessing it was the HBN. Not to worried

 

[PathFinder]

Thanks for posting up the doppler data, that will be really useful here shortly.
Dies showed up last week, and a SAC .271 bushing on Monday. Chronograph may show up Friday or Saturday. Once it does I'll do a workup with H1000 and N568 to see what they're capable of. I'll also post an actual velocity from the current N570 load.
My sizing die is set up to bump shoulders .002-.003, and fireform loads with 55gr of 7828 SSC and 105 Berger Hybrids are pushing the shoulders out to exactly that same dimension. That's working well but I'm going to give fill-less fireforming a shot today, I'll post results from that attempt.
Ryan, any estimate of barrel life from current throat erosion yet?

 

[hdc77]

Thanks for posting up the doppler data, that will be really useful here shortly.
Dies showed up last week, and a SAC .271 bushing on Monday. Chronograph may show up Friday or Saturday. Once it does I'll do a workup with H1000 and N568 to see what they're capable of. I'll also post an actual velocity from the current N570 load.
My sizing die is set up to bump shoulders .002-.003, and fireform loads with 55gr of 7828 SSC and 105 Berger Hybrids are pushing the shoulders out to exactly that same dimension. That's working well but I'm going to give fill-less fireforming a shot today, I'll post results from that attempt.
Ryan, any estimate of barrel life from current throat erosion yet?

Im so looking forward to your results, I have everything ordered so I figure in a couple months I should Be up and running with my 6 UM. Never thought I’d buy a 6 mm x hunting but here we are.

 

[khuber84]

I figured It would, but not that much.

Now I need to +p and HBN…. YES

Do you have enough spare case capacity to get the pressure/velocity back up with the additional +p/hbn? Those two together are probably gonna drop 100-120fps from prior load. That's gonna need another 2gr +- N570 to get back the lost velocity.

 

[Ryan Avery]

Yes, @PathFinder is running a 6UM +p and HBN now

 

[PathFinder]

Yes, definitely. The case will hold ~72 grains of N570 and still seat a bullet without unreasonable powder compression. I hit pretty high pressure at 69 grains and stopped there.

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[BjornF16]

Exactly, my numbers are very similar. Considering wound channels in place of bullet diameter/mass/energy leads to a much more effective setup overall. Watching impacts, even in less than ideal positions, is a big advantage.
Picture is 300 WSM w/208 ELD-M at 3.020 COAL next to a 6 UM. 6 UM has the same MER or slightly more, and better external ballistics.
My 300 WSM has been very effective, but I'm not convinced it does anything terminally that a 6mm/6.5mm doesn't, at significant cost in recoil and shootability.
View attachment 561987

Need to get brass headstamped with 6UM so I can take to Africa

 

[PathFinder]

I'm starting a 6 UM reloading thread in the Reloading forum. Fire forming results will be first and then I'll have data for workups with 4 different powders, including velocities, tonight or tomorrow.

 

[amassi]

Need to get brass headstamped with 6UM so I can take to Africa

I’ve never traveled with firearms in Africa but do they measure the projectiles? Just stamp your barrel 6.5 saum and your gtg


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