This past summer I built 2, 20BR's, one for me and one for a buddy. They are built on Savage Target actions, mine a left port/right bolt, and my buddies is a duel port/right bolt. Both have Pac-Nor S/S 26", 3 groove, 1:12 twist, #7 contour, super match barrels. Both have Richards stocks.
Since I had several hundred pieces of brand new 7mm BR Remington brass left over from a 22BR build several years ago, we decided to use that brass, in leu of new 6mm BR Lapua brass. We started working loads with 40gr Hornady V-Maxs and since I have 24 pounds of BLC2 powder on the shelf, we started of with that powder. We started at 29.0gr of BLC2 and worked up to 35.0gr. To our suprise and delight, both rifles loved 34.5gr of BLC2 and the 40gr V-Maxs. Both rifles shoot that combo into high .100 to low .200 groups at 100yds and around .8" to 1.2" at 300yds, depending on wind. Both loads for each rifle are interchangeable, which is a plus since we shoot and hunt alot together. Velocties are pretty close as well, just 14FPS apart average, at 4,128 and 4,142 FPS. This load is fast, as it almost an instantaneous "ding" when shooting 6" square hanging steel plates at 400yds and I like not having to make any "click come ups" or take the cross hairs off the plates at 400yds.
Longest shot so far is a 462yd kill on a groundhog. Out to 300yds, it desinagrates a groundhog's head. I have shot crows and foxes as well and it does the job real well on them also. I love to see the pooooof of feathers when I explode a crow. To sum it up, anything under 400yds is a dead critter, if I get the crosshairs on it. The 20BR is a varmit hunters dream rifle.
I use Wilson 22BR in-line dies, with a .231" neck size bushing. I had to make a new 20 cal decapping rod for it and a 20 cal bullet seater rod. My buddy uses Redding 20BR dies, with a .231" neck sizer bushing.