Anybody here put one together? I've almost got all my parts and was wondering what others have done.
Let's hear about and see yours if you got one.

how does it differ from Warren Pages old Mashburn Magnum???

Its basiclly a blown out/ re-necked 300 H&H i think. Im pretty sure its parent cartridge is 300 H & H . I knew a guy in a hunting club in the 90s that had 1. It pushed 168 at around 3200 fps. When it shot -out he re-reamed it to 7mm mag.

It's still the same as Warren Pages Mashburn. In today's time more people are just useing 300 win mag brass and bumping the shoulder back and necking down to .284. It's as simple as running your 300 win mag brass thru your full length 7mm Mashburn die until you get a light crush fit when you close the bolt. Then load it up with around 65gr. Imr4350 and a cheap 140gr. bullet to fire form.

I'm also working with a old pre prefix Rem 700 in 7mm Rem mag. I wasn't happy with the factory configuration so I tore into it.
New stock is a Mcmillian Classic with the molded in Rhino camo. The barrel is coming from Brux. SS 1 in 9 twist #4 contour fluted, finished at 25.5". Trigger will be a Jewell set at 1#.
I'm still up in the air on the bottom metal. The stock is cut for Remington's standard BDL floor plate.
I can run up to 180gr with that twist but I'll most likely stick to the Hornady 162gr. AMax at around 3200 fps. It should be a great long range hammer.

I have never had a Brux barrel. I have had = Kreiger, Bartlein, Shilen, Broughton, Lijia, Rock, and Pac-Nor. But I have heard Brux is coming on in the benchrest world? Sound like a good rifle your building though. I would like to try a Brux some day myself.

Wait time is a killer with Brux. But like you, I've heard good things about there barrels. I ordered back mid August and was told 8 months. It should be soon. Mcmillian is getting better on there delivery dates. The first one I ordered was a 9 month wait. The newest came in at 5 months