The 6UM

JQuaglino

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Jun 21, 2022
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I'm interested in your dtac experience.
I've been using 109 eld-m and they haven't let me down but those dtacs look mean
If someone has built one I would love to chat with them. I haven’t found one yet searching the internet.
I have found lots of info on the 6mm SAUM but not an improved version.


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What makes it improved? I’m assuming bullet angle and if so what is the difference?
 
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What makes it improved? I’m assuming bullet angle and if so what is the difference?

Generally "improved" means fireforming the brass to have more capacity than parent cartridge via 1 or more of the following:
  • Making case shoulder angle steeper
  • Blowing the shoulder further forward
  • Reducing the case body taper
More capacity = more powder = mo faster

Less body taper, steeper shoulders = Less case stretch

There are improved variants that push the shoulder back some too which makes the neck longer.
 

JQuaglino

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Jun 21, 2022
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Generally "improved" means fireforming the brass to have more capacity than parent cartridge via 1 or more of the following:
  • Making case shoulder angle steeper
  • Blowing the shoulder further forward
  • Reducing the case body taper
More capacity = more powder = mo faster

Less body taper, steeper shoulders = Less case stretch

There are improved variants that push the shoulder back some too which makes the neck longer.
Thanks. I was hoping to get the cartridge differences between the 6 um and a 6 SAUM.
 
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Ryan Avery

Ryan Avery

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Shoot2HuntU
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e2b2852f1ab8a45c588d591c3a949d17.jpg


She will fit in a short action.


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JQuaglino

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Jun 21, 2022
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Do you think the right bullet for it exist currently? That’s a screamer with some serious propulsion behind it. Just thinking about. Seems a big gap between the a 105 to 115 bullet to the 147s and 156s that 6.5 saum and prc shoots.
 
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Ryan Avery

Ryan Avery

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Do you think the right bullet for it exist currently? That’s a screamer with some serious propulsion behind it. Just thinking about. Seems a big gap between the a 105 to 115 bullet to the 147s and 156s that 6.5 saum and prc shoots.
The right 120-grain bullet would be nice but more bullet more recoil.
 

JQuaglino

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Jun 21, 2022
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The right 120-grain bullet would be nice but more bullet more recoil.
Very true. Would a 120 class bullet cut the wind better or worse or would it be a zero sun game because it’s a higher weight longer bullet yet slower speed. Compared to 105 to 115 bullet respectively?
 

amassi

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May 26, 2018
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Very true. Would a 120 class bullet cut the wind better or worse or would it be a zero sun game because it’s a higher weight longer bullet yet slower speed. Compared to 105 to 115 bullet respectively?
Not a lot of fat to trim with the 108-118 class 6mm, at 5,000 ft they're 9 mph wind # and drop less than 5 mils at 1000 at the velocity Ryan's getting with the 6um.
 

JQuaglino

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Jun 21, 2022
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Finally got some rounds loaded. Should have some speeds next weeks. I started with VV565 but I don’t think that will be “the powder”

The water capacity is 75g

6UM next to a 6CM

5816b4c3d384612497e7dbd600aac097.jpg



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What was the overall length on the bullet for the 6UM?
 
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