I finally got my 3 Romys and a Tantal done last week. One Romy was easy - used a hand sledge and 1/4 in pin punch. One horrible, one slightly less horrible, and the Tantal an absolute @#$%!
I bought a standard 6 inch industrial duty vise from Harbor Freight ($44 after discount coupon). Made a series of drive pins from old 1/4 inch drills, starting at about 1/3 inch. Ground a cheap 3/8 inch socket to fit the left side of the trunnion to leave space to drive the barrel pin into.
Then I stuck the socket and shortest drive pin on with contact cement (not having 4 arms to hold it all together) put it in the vise, drive pin on the right side (looking from the breech) and used a piece of pipe on the vise handle to crank it down until the drive pin almost began to buckle. then I whacked the handle jaw of the vise with the hand sledge.
It moved the pin a bit, did it again until the vise was up against the trunion, opened it and put in the next longer pin, repeated until the barrel pin was out.
One popped, and driving the pin out got easier. The other one didn't, just fought me most of the way, and the Tantal was worst of all.
If your drive pins buckle or barrel out too much so they dont drive out the barrel pin, just cut shorter and more pieces to prevent it. I had to use 5 pieces on the Tantal as the vise just squashed the longer ones I used before. As it got to near the end and I had to take my slightly too short socket off the trunnion the pins were finally loose enough to drive out with punch and hand sledge.
As there have been reports of pin driving jigs coming apart in the presses without moving Romy pins and old drill bits are free, I feel that this is the most effective and cheapest way to remove those stubborn barrel pins.