I got my detachable mag bottom metal from Stockade in. It is quite simple in design. But perfect!!!
At first I was worried about how it would look with the bottom metal hanging out the bottom. I actually really like the way it looks. So far it functions perfectly and allows for a OAL of 3.85". I started with a Savage RUM action with a CRF bolt head and a 338 lapua mag from Accurate mags. I tweaked the Mag to take the RUM case (pain in the butt) then sent the action and mag to Kevin at Stockade and he made me the bottom metal. He said it was the first one he had built with the OAL of 3.85" (I think he had worked with some 3.75" mags before). The bottom metal only weights about 4 oz. The mag is quite heavy when filled with 5 rounds of 338 edge and 300SMKs. The rifle is not near done but will be sweet when finished. I will be getting a 28" barrel (I think a pac-nor 3 groove).
[img width=600 height=400]http://i16.photobucket.com/albums/b23/tule-man/IMG_1325.jpg[/img]
[img width=600 height=400]http://i16.photobucket.com/albums/b23/tule-man/IMG_1329.jpg[/img]
[img width=300 height=450]http://i16.photobucket.com/albums/b23/tule-man/IMG_1330.jpg[/img]
I already have
savage rum action
Lone Wolf Palma Master carbon fiber stock. (was on my300WSM and I had to re inlet it for a long action.)
Stockade bottom metal
Stockade Recoil lug
Target Accu trigger (on the way.)
1.25" Carbon fiber tension tube
1.25" Holland style muzzle brake
SSS bolt handle
EGW 20moa base
Burris extreme rings
Bushnell 6500 elite 4-30X50

I still need
A barrel
flush mount sling swivels
Paint

All said and done I think I will come in at 10.5-11lb with the scope without the Bipod.