50 BMG Primer Popper the safe way

I have about 75 rounds of primed 50BMG brass that I am going to make dummy rounds from. The brass was all FL sized and primed before it was found it would not chamber in my gun. It was fired in a friends 50 rifle. His rifle has a sloppy chamber that allows the brass to expand about .005 right at the head. That bulge cannot be taken out by my dies as that portion of brass is too low to be sized.
I have pushed out a few of the primers with my sizing die, but chickened out after a while. If you have ever heard one of these go off in the open it would scare the heck outta' you.
I designed this 3/4" pipe popper. With the help of my gunsmith, he drilled the pipe cap and machined a firing pin from a bolt to mount in it.
Put the brass in the pipe, screw on the cap, drop the whole thing onto a 3/8" steel rod that is stuck in the ground, then whack it with a hammer. Most of the primer is blown out under the cap and the gasses are vented down, mostly on the outside of the brass and out the bottom. The outside of the brass is blackened with primer residue, but that will clean up.
I also droop an old T shirt over the whole thing before popping it. The explosion is "surpressed" and made into a mouse pop.

RGT have you got pictures? I'd like to see your rig.
I have about 15 live primers that I pushed out and will probably get rid of them by the fire pit method. Rather noisy and dangerous if you are too close. A shame as these cost me on the order of 45 cents each when new.
Oh well, as the Gunny sez: "It's only money."

I make dummy rounds of it. Sent some to the Gunny as wall decor.

A dandy device RG1. Yours is really designed to de-cap while my was planned to fire the cap. Mine vents the primer gas around the outside of the brass as the unsupported primer blows out the rear, then down and around. Mine is surprisingly quiet. So far no shrapnel exits around the supporting 3/8" support rod. (but I always wrap an old rage around same to make sure.) Thanks for the picture and answer!