I loaded a bunch of Fiocchi shells trimmed down to 67mm. That is slightly longer than 2 1/2”. It is 2.6378”. 2.5” is 66.04mm. So less than a mm longer. Why you may ask? 65 and 67mm CIP shells are approved for use in 2 1/2” chambered guns in proof. I was able to load with standard wads, common powder and Fiocchi primers. And I can load them on my progressive loaders.
I have sent several strings of test loads off for testing pressures and velocity. Until I get those results I’m just waiting. But I used Unique powder in a 1 and a 1/16 ounce loads with loads which would have been very modest with 1 1/8 ounce. For what I shoot 1 1/8 ounce is overkill. Unless I get extreme velocity variations I will be very happy. Everything fits, I can get more of what I need and don’t need to stock yet another special use wads.
You can roll crimp a 2 3/4 “ load in a 2 1/2” hull. But Fiocchi are not that long to begin with and there is a lot of internal volume in that straight wall case. Trim few down and try loading them at 67mm. Have them tested for pressure and velocity. Being able to just use a normal star crimp speeds up loading from a box now and then to loading hundreds an hour. And I had two 8 pound jugs of unique powder on hand.
I trimmed the Fiocchi hulls down to about 2.53" and used 20.5 grs of Clays, a 1 oz load and the CS12S Comp Special Short 12 g. That made the load column way too short so I tried adding 2 .125 card under the wad and roll crimped the hull. Loads felt very light (6.8 lb gun), left a lot of un-burnt powder and given how far behind I was on the skeet birds, was probably at 1100 FPS or slower.
I certainly appreciate everyone's input so far, but it probably going to be a moot point within the next month or so.
I'm buying a used Mec 600 JR and with the MEC adapter for 2.5" hulls I should be able to use star crimps which I suspect will solve many of my problems and if I don't already have a fully adjustable bar for the MEC, I'll buy one. As a long time cartridge reloader I'm used to a fully adjustable powder dispenser so relying on the bushing system is very frustrating for me due to the relative lack of precision of the powder charge. I didn't start loading smokeless shotguns until about a year or so ago .
