6 PRC or 6um?

[westcoasthunter]

So I have a .243 barrel being fluted and cut to 20” right now it’s a 7.5T.
I was wondering what your thoughts are. I smith has the 6prc reamer already I would have to buy the 6um reamer and gauge if I went that route.
I’m hoping to run the 108 eldm or the new 116 TMK . what’s everybody’s thoughts between the two and which one would you go with? Also, if you have any real world experience on velocity comparison with the 20 inch. Thank you

 

[JohnsIsl]

I think there are two inputs into the equation and the output is performance. Two inputs are: amount of work you want to put in and brass availability. I really like 25PRC because it is an easy one-pass neck down to 257. I think 6PRC may require two passes? But high quality 6.5PRC brass is a dime a dozen.

A 6UM-30 is pretty great if you can get brass. A 6UM-40 is probably more work (fire forming) than I would want - but if you want to eke out every last drop of performance.... then that is probably your huckleberry.

I think there is also a 6PRC from Primal Rights that has a 40 degree shoulder.

 

[TradLife406]

The 6 UM 40 is pretty legit. I love mine.
Fire forming was actually a lot of fun. An excuse to shoot 100 rounds from my new rifle. Buying dies and brass last year wasn't too bad.

Went ahead and bought two of the LS Wild group buy barrels last December. I'm about halfway through the barrel I bought from Avery.

It was pretty awesome shooting my bull at 905 last fall. Then the next morning my buddy came in with horses. He was surprised at the shot and how it only took one impact (I did give the bull a warning shot to be sporting).

Though I'll admit I'd probably be fine with a short barreled 22 Creed for 90% of what I do in Montana. The UM-40 is a beast of a round. But yet I can shoot it and not blink during recoil.

 

[westcoasthunter]

So the 6 prc and the 6uM-30 are probably pretty close and the 6um-40 is a little above that but with more work.

 

[WeiserBucks]

So the 6 prc and the 6uM-30 are probably pretty close and the 6um-40 is a little above that but with more work.

Sort of. PRC and UM-30 can use off the shelf bushing dies and don't require FF. Similar velocity. UM-40 will require custom dies and FF, highest velocity of the three.

 

[PathFinder]

If the goal is absolute max velocity: 6 UM-40
If a balance of performance, barrel life, and availability is more important: 6 PRC

The UM-40 is going to be faster when burning N570, no question about that. But the PRC has some attractive attributes. Lapua brass, easy dies, utilize H1000 for better barrel life, there's a -3 quick drop at 3100 fps in meters... The one thing I haven't found readily available are reamers with proper (~.180") freebore. But if your smith already has one, that's not an issue. 6 UM-40 reamers are currently out of stock, though brass has good availability.