6UM alternative

[rifletuner]

The 6-284, 6-6.5 PRC, 6-06, 240 Wby all have pretty much the same case capacity right around 66-67gr H2O depending on brand of brass and if you measure it new unfired or after its been fired. The 6-06AI has a little more then those others and is real close to the same as a 6 RSAUM they hold about 71-72gr H2O. The 6UM and 6-6.8 Western are near twins at about 75gr H2O then the 6 WSM has a little more boiler room at 78-79gr H2O.

The SAUM, UM, WSM, and Western will all need a mag bolt face while those others use a standard bolt face size. Most of them will work in a short or Tikka size action but except the 240 Wby or anything based off the 06 case, those two need a long action.

Generally, more case capacity means more velocity but once you get to a certain point of overbore, unless you plan to run exceptionally long barrels, there is a point where you start seeing little increase in velocity for the amount of powder being used.

IMO, the 243Win/6 CM size cases which is right around 51-53gr H2O is kind of the "easy button". They do everything pretty well, are easy to load for, and have pretty decent throat/barrel life. If you want more velocity then either of those the 6-284 and 6-6.5 PRC are also pretty easy peasy. That's not to say that any of the others are difficult per say but like most things it's all about trade offs.

With ADG making quality brass for the 6.8 Western I can see that becoming a very popular case to build 6mm, .257 and .264 wildcats off of.

Why wont a 240WBY or 6-06 fit in a Tikka action? Or are you just saying it will limit the seating depth of the bullet in these actions?

 

[B23]

Why wont a 240WBY or 6-06 fit in a Tikka action? Or are you just saying it will limit the seating depth of the bullet in these actions?

You can certainly use a Tikka you'll just have to seat the long heavy for caliber bullets deeper in the case.

 

[Formidilosus]

You can certainly use a Tikka you'll just have to seat the long heavy for caliber bullets deeper in the case.

What’s the coal of a 6-06 with a 115gr DTAC, 108gr ELD-M, etc. seated with the boattail at the neck/shoulder junction?

 

[eLightfoot]

I think the sweet spot is 6rem. But the brass situation sucks. The most over looked opportunity is a wildcat off 6.5x55 lapua brass. Widely available and just a tad over $1 a piece. 22 and 6mm improved versions would haul ass. If you’ve got a tikka or LA donor