The 6UM

Spoonbill

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Could you tell if the bullet actually tumbled ?


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I wasn’t there when any of the animals were gutted and I unfortunately deleted the pictures of the entry and exit wounds so I can’t say for certain. If any of them use fort scott ammo this year when we go deer hnting I can try and take some autopsy pics.
 

Formidilosus

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I kind of asked, had to back track.

Still curious what to look for in a bullet that tumbles compared to expands In the manner I think of traditionally

Not a bullet engineer, however all bullets will yaw (tumble) inside tissue IF they don’t upset from the front. The problem is getting them to do it consistently and early in the wound channel, and the bullet to be large enough (long) to cause good wound size. If I remember correctly, 3 plus caliber length long bullets is where they start doing it well. There are some other design considerations (nose profile, boattail length and sharp, etc) that can help, but it’s mainly long for caliber bullets and none “expanding”. I think, the DTAC nose breaking off helps at lower impact speeds to destabilize the bullet and cause it to yaw more consistently.
 
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Fort Scott has a lead free bullet designed to tumble upon impact. I’d like to try them out for lead free California if they would better than the lrx


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I’ve been wondering about their ammo as well. Bomgaars started carrying them I believe in .308, .233, and maybe 9mm? I’d never heard of them and was suspicious about their “TUI” technology.
 
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Ryan Avery

Ryan Avery

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fecafd61fd6d44be0f624594f95fc90c.jpg

d2b36d10500fbea9f33a75bdae2bf4d2.jpg


She’s headed down to kill a cow elk tomorrow.


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@mullmann

Gun shoots great, no recoil, quiet, great package. When it came to the cow there was little time to get a great shot and my position was garbage, clean miss, cows only.

Did go back in the evening and looked in a couple other spots for more and no more opportunities for shots.

Was very impressed with the splash of that 115 dtac even at 1200 yards taking some shots prior to the hunt.20230827_193458.jpg
 
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Kurt

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Oct 10, 2012
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I have had this rifle for a few weeks now, it is a 6 UM put together by Jake at UM. Below are the specifics on the rifle.
IMG_4636.jpg
Tikka T3 Lite 300 WSM Action
Proof Research 24” Sendero
MDT HNT 26 Folding stock
NF NX8 2.5-20 F1 Mil
CGS Hyperion K Suppressor

Weight is 9.1 pounds. I have had it in another config without the can, one of Ryan’s brakes, non-folding stock, and a NF 2-10 NXS. While I was able to reduce weight by approximately 1.2 pounds in this set up, I have found I shoot it much better in the current configuration. I know you could also save weight with a lighter/shorter barrel if that was a priority.

Load development was fairly quick, I started with Ryan’s data using N570 powder and Dtac 115 HBN. I worked loads from 64 up through 67.5, settling on 66 grn at 2.95 coal. Velocity is 3430 as validated at range and Lab Radar. Jake at UM was kind enough to set me up with fire formed brass to get me going, and dies are on order expected any day. So far there is 170 rounds though the barrel. For those interested in the specifics of the load development, I will make a post on the 6 UM reloading page as well.

While there may be more options for mags, I have been using several MDT styles. The 7 round short action magnum mag was a little longer than I preferred in a hunting situation, so I have a couple of the 3 round mags with 2 round extenders on them. The spring has shown to be slightly weak with the 4th and 5th rounds not feeding consistently. I took them apart and stretched the spring a bit, now they feed well. I then modified a 10 round 308 MDT mag to fit, which was very easy by simply opening the top jaws slightly with a set of pliers. It does not take much, open approximately .035 using a caliper and needle nose pliers, it is a couple minute operation. They become a 6 round mag for the 6 UM. Given this is the same size mag I use on a 6 and 6.5 CM, I am leaning towards these mags for hunting. Both mags are approximately 1 oz per round.

Using the short magnum magazines, you are limited to 2.95 coal for a clean feed. This puts me .060 off the lands, it has proven to shoot very well with this jump.

Let me know if there are any questions. Overall I am very pleased with the rifle and greatly appreciate Jake at UM for putting the rifle together for me, and Ryan for his expertise on the loading and parts side.
 

NSI

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I have had this rifle for a few weeks now, it is a 6 UM put together by Jake at UM. Below are the specifics on the rifle.
View attachment 596378
Tikka T3 Lite 300 WSM Action
Proof Research 24” Sendero
MDT HNT 26 Folding stock
NF NX8 2.5-20 F1 Mil
CGS Hyperion K Suppressor

This is such a well thought-out setup. Nicely done. I'll be stealing your MDT mag hacks.

-J
 
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Ryan Avery

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@mullmann

Gun shoots great, no recoil, quiet, great package. When it came to the cow there was little time to get a great shot and my position was garbage, clean miss, cows only.

Did go back in the evening and looked in a couple other spots for more and no more opportunities for shots.

Was very impressed with the splash of that 115 dtac even at 1200 yards taking some shots prior to the hunt.View attachment 596023
It looks like 6UM country.
 

9.3koolaid

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Feb 2, 2017
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136
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Alaska
Let me know if there are any questions. Overall I am very pleased with the rifle and greatly appreciate Jake at UM for putting the rifle together for me, and Ryan for his expertise on the loading and parts side.
When does the suppressor wrap come out?
 

Kurt

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Ryan,
It performed very well on elk, one shot at 505 yds, it was over quickly. Bullet did exit, both entrance and exit were through the ribs right behind the shoulder. Based on the exit hole, the bullet appeared to keep a substantial amount of mass. Neither entrance or exit showed the amount of blood shot that I have seen with the 108 ELDM, for whatever that is worth based off one shot.

9.3koolaid,
Still working on the suppressor cover, that fabric is a little bit tough to work with on finishing edges, I need to figure that out. Will keep you posted though.
 
Joined
Sep 8, 2014
Messages
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Location
Front Range, Colorado
I have had this rifle for a few weeks now, it is a 6 UM put together by Jake at UM. Below are the specifics on the rifle.
View attachment 596378
Tikka T3 Lite 300 WSM Action
Proof Research 24” Sendero
MDT HNT 26 Folding stock
NF NX8 2.5-20 F1 Mil
CGS Hyperion K Suppressor

Weight is 9.1 pounds. I have had it in another config without the can, one of Ryan’s brakes, non-folding stock, and a NF 2-10 NXS. While I was able to reduce weight by approximately 1.2 pounds in this set up, I have found I shoot it much better in the current configuration. I know you could also save weight with a lighter/shorter barrel if that was a priority.

Load development was fairly quick, I started with Ryan’s data using N570 powder and Dtac 115 HBN. I worked loads from 64 up through 67.5, settling on 66 grn at 2.95 coal. Velocity is 3430 as validated at range and Lab Radar. Jake at UM was kind enough to set me up with fire formed brass to get me going, and dies are on order expected any day. So far there is 170 rounds though the barrel. For those interested in the specifics of the load development, I will make a post on the 6 UM reloading page as well.

While there may be more options for mags, I have been using several MDT styles. The 7 round short action magnum mag was a little longer than I preferred in a hunting situation, so I have a couple of the 3 round mags with 2 round extenders on them. The spring has shown to be slightly weak with the 4th and 5th rounds not feeding consistently. I took them apart and stretched the spring a bit, now they feed well. I then modified a 10 round 308 MDT mag to fit, which was very easy by simply opening the top jaws slightly with a set of pliers. It does not take much, open approximately .035 using a caliper and needle nose pliers, it is a couple minute operation. They become a 6 round mag for the 6 UM. Given this is the same size mag I use on a 6 and 6.5 CM, I am leaning towards these mags for hunting. Both mags are approximately 1 oz per round.

Using the short magnum magazines, you are limited to 2.95 coal for a clean feed. This puts me .060 off the lands, it has proven to shoot very well with this jump.

Let me know if there are any questions. Overall I am very pleased with the rifle and greatly appreciate Jake at UM for putting the rifle together for me, and Ryan for his expertise on the loading and parts side.
Very solid work, I like that configuration. It's good to see a few rifles now that are very near the same powder charge and velocity. Appreciate the terminal update as well.
 

Wapiti1

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Sep 18, 2017
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Couple of questions. What would make you choose 1:8 or 1:7 twist? For the non-suppressor hold outs (I know, I know) what barrel length would one choose?

I've got a little different thought on cartridge because there is a Howa .270 sitting in the shop needing a new life. It's whispering 6mm-06 AI. Should be very comparable to the UM.

Jeremy
 
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Ryan Avery

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Couple of questions. What would make you choose 1:8 or 1:7 twist? For the non-suppressor hold outs (I know, I know) what barrel length would one choose?

I've got a little different thought on cartridge because there is a Howa .270 sitting in the shop needing a new life. It's whispering 6mm-06 AI. Should be very comparable to the UM.

Jeremy

I would highly recommend a 7.5 or 8 twist if you're planning to shoot ELD-Ms or NR Dtacs. If you're shooting without a can, a barrel length of 22 to 24 inches will be more than sufficient. If you want 3500+ go 26 inches or longer.
 
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I went with a 24" 7.75tw hawkhill........will run suppressed if I can spot my own impacts past 400y, if I can't, it'll have a brake.
You shouldn't have any issue spotting those. Shot Ryan's this last weekend for a few shots and when steady could get right back on them 16.75" +can.

If I wasn't in a good position then obvious results.
 
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