Hi all, Calibros did not try to regulate the barrels on his 45-70. He did try to adjust his loads to get them to regulate, but didn't have much sucess with it. He has the sights set for the right barrel and gives a little windage for the left one. He says after recutting the sear engagement that he hasn't had any more doubleing mishaps. I don't have a current picture of his " Pondoro", but he says that he has finished the ends of the barrels.

On my site I have pics of my 70cal pinfire Howdah. The recoil is not that bad.

The 470NE being built on the Belgian Antique 12ga may not look pretty, but it does shoot and has not come off face yet. It did pass with 2 heavy proof loads and several box's full power loads since then. I have been slow on finishing it. I have one barrel soldered in place and just need to get back to the range to finish adjusting the left one. With the barrel sleeves turned to the shotgun dimensions then the barrels didn't even come close to regulateing. The right would shoot left and the left would shoot right about 18" at 25yds. I then turned down the barrels tapering them back but leaving a full diameter for abit at the muzzle end, then I went to the range, filed down one side of the barrel, shimmed it over and shot. Repeat. I got it shooting fairly good at 50yds, but ran out of ammo. My next trip to the range should be able to get the left barrel adjusted and soldered in place.

I informed Calibros of my regulating idea. I don't know if he will try it on his 45-70 or not.

Reading the ATF code, it seems that it should be legal to build a Howdah from an anitque double shotgun. I wrote a couple of letters and several email to the ATF. They responded saying that a cut down shotgun would be a sawed off shotgun and would need to be liscenced. They did not address the issue of starting with an antique as the CGA and NFA do not apply to anitques.
If you have different rules in Australia then I wouldn't see any reason that you couldn't do it. I would start with a shotgun that has the 3rd fastener on it. A dolls head or the greener cross bolt. I would think that a 50-70 would make a very nice Howdah caliber. A quick run through Quickload shows that a 10" 50-70 with 500gn cast should be able to do 1200fps+ and stay under 27ksi with 26gns of 2400. That should be pleanty of performance out of any pistol.

If you don't like the looks of a sleeved 12ga, then you could always cut the barrels off around 3" and make a monoblock out of it. Thread the monoblock, then screw your barrels into it, solder in place then finish and regulate like a normal double. I may try that on my next one after I get this one done.