The 6UM

[Clownbuster]

I ordered the dies back in August from UM, I don't think ordering them from Whidden directly would get them to me faster. However, I've pretty much decided to bail on the 6UM and go 6 SAUM.

I started the project trying to get a DTAC going over 3200 since I couldn't get there in my .243 AI. Looks like the 6 SAUM will easily do what I want and I can use the same dies with a different neck bushing if I decide to do another SAUM down the road (I think 25 SAUM would be fun and I already have a 6.5).

As far as brass I thought the 6 UM brass was just a 6.5 SAUM necked down to 6mm, I'd bet that's the case as that's a relatively simple change to the process compared to a whole new set of case dimensions. A run through the sizing die would fix it anyway.

The whole idea of the 6UM was great when it first came out, buy the reamer (which was not proprietary at first) and take it to your local gunsmith and have them cut a barrel. Now that it's all proprietary it's a tougher proposition.

There have been some changes to the first released reamer. Clickers were developing in fired brass past the .200" line of the chamber, so they widened the reamer .002" to solve the problem.

 

[Elkster23]

I ordered the dies back in August from UM, I don't think ordering them from Whidden directly would get them to me faster. However, I've pretty much decided to bail on the 6UM and go 6 SAUM.

I started the project trying to get a DTAC going over 3200 since I couldn't get there in my .243 AI. Looks like the 6 SAUM will easily do what I want and I can use the same dies with a different neck bushing if I decide to do another SAUM down the road (I think 25 SAUM would be fun and I already have a 6.5).

As far as brass I thought the 6 UM brass was just a 6.5 SAUM necked down to 6mm, I'd bet that's the case as that's a relatively simple change to the process compared to a whole new set of case dimensions. A run through the sizing die would fix it anyway.

The whole idea of the 6UM was great when it first came out, buy the reamer (which was not proprietary at first) and take it to your local gunsmith and have them cut a barrel. Now that it's all proprietary it's a tougher proposition.

I jumped on the wagon bought the dies ordered a reamer. I have the rifle finished but didn't have brass. I ended up going with 6.5 saum adg brass. I'm still waiting on my "6um" brass I was told would be here in October, then first part of December. Still waiting. While I have shot the rifle and got a load worked up. It's shooting the dtac at 3250 in an 18in 1-7.5 twist. If I had to do it all again I'd go the 6 max from sherman wildcats. They have everything in stock, dies, brass, and reamer. Since I bought the reamer I'll stay with the 6um for now.

 

[khuber84]

There have been some changes to the first released reamer. Clickers were developing in fired brass past the .200" line of the chamber, so they widened the reamer .002" to solve the problem.

0.552 is the best dimension for Saum chambers at the 200 line, and a good tight sizing die like the micron, or matchmaster FL bushing die. The other option, buy Cortinas small base mandrel die, which is cheap, and use that to size the base tighter after or before FL sizing.

 

[omicron1792]

Anyone loaded or shot the 80gr eld-vt?

 

[andarch]

Anyone loaded or shot the 80gr eld-vt?

Yeah, in my 6 ARC. 6 CM has load data getting 3350 fps, I bet the 6 UM would vaporize the thing.

 

[The Fish Box]

The 6UM might at well be a unicorn at this point, I have been waiting for my rifle since February almost starting to get impatient. Hope to at least have the whiden dies when the gun shows up and then neck down the 6.5 sauna brass until my 6UM brass shows up.

 

[andarch]

Amazing grouping with the 80g ELD-VT in the 6 ARC though, my gas gun was shooting cloverleafs at 100 meters.

 

[Andrew31]

Has anyone reached a reload limit on brass? Current count on reloads?

 

[andarch]

Any beta testers have a piece of unfired 30° 6um brass that I could borrow to get a shoulder datum measurement on? I'll pay shipping both ways.

I requested info from UM on the shoulder datum line of the 6um 30° chamber print, so I could compare it to my 6/6.5/7/300 Saum prints. They all use the same exact 0.460 datum line, all the same Saum go gauge. All in wanting to know is how much deeper I need to set a standard Saum chamber to fit the 6um 30 brass. Here's UM's response:

"The reamer specs are still in flux. So I can't comment on that at this time. Having said that, those details will likely remain private unless you buy a 6UM reamer.

The 6UM 30 is not just a 6 SAUM. 6UM 30 brass will not fit in a 6 SAUM chamber.

The reamer is now and the dies will be available shortly! We sincerely appreciate your interest.

Thank you"

So from sounds of it, nobody will know the actual difference in headspace between Saum and um30 unless you buy from UM.

So it the reamer is available now "the reamer is now and dies will be available" how are they still in flux "the reamer specs are still in flux"?

 

[khuber84]

So it the reamer is available now "the reamer is now and dies will be available" how are they still in flux "the reamer specs are still in flux"?

You can order and pay for something that likely doesn't yet exist. Sounds very rokstok. However jgs will not have the hangups stockys has. 3 months is pretty much the golden rule with them.