Have you ever tried to form 30-40 brass from brittish 303 brass? Just wonderin how they worked?

To borrow a quote "That is some scary stuff" most of the advise on the Internet is repeated, in the beginning there were stronger rifles that were chambered for the 30/40 Krag ammo, many of the rifles were shipped to Africa and Canada, those that found themselves out of the country with a Krag chambered rifle found themselves out of ammo (eventually?), so they used 303 British,, a case that is shorter by as much as .091 thousands and a shoulder that is forward of the Krag by .065 thousands. If there is an advantage it is with the 303 Shoulder, it is ahead of the Krag shoulder by as much as .065 thousands meaning when sizing/forming a 303 to 30/40 Krag the reloader can put the shoulder of the case at the shoulder of the chamber (if the reloader knows when to quit sizing). We all know both cases are rimmed and head space on the rim and the thickness of the rim determines head space (in the perfect chamber), placing the shoulder of the case at the shoulder of the chamber cuts down on a lot of case traveling, this method could be called form first then fire instead of fire to form, fire forming is is major trauma on the 303 and 30/40 cases.

And the case body expands .009 thousands + or - a few, I am not a fan of the Krag rifle with one lug. Ackley developed an improved version of the 30/40 Krag chamber, not for the one lug chamber, he developed the improved chamber for the other rifles, the ones with a different lock up system, and his version was an improvement.

How do they work? I do not like a big gap between the end of the case and the beginning of the throat and I am not in need of something to shoot. except for the one lug bolt I like the way the pieces go together, like an old wood plane that is refereed to as being transitional, had Springfield learned anything going from a single shot builder to a builder of repeater they would not have made so many mistakes on the 03, we know the Mauser was the better rifle, when we returned from Cuba we knew we had to catch up, so Springfield and Rock Island built 1,000,000 ++ rifles that were suspect, and I am thankful the British provided us with the equipment and design to build the M1917, as a P 14 the rifle was a very fine 303 British chambered rifle, and it makes a very fine 308 Norma Mag..

Then there is the primer, most 303 British cases have Berdan primers.
F. Guffey

Just run a few .303's into your 30-40 dies, put in 10 grns of unique, some cormeal and a wax or toiletpaper stopper and fire it. Pressure is enough to form the case but is no way going to do anything to the rifle. See how they look then.

Most people do it the other way, uses 30-40K in a 303 as the brass is 0.002" thicker in the neck. Useing 303 brass you will end up with a neck that is .004" smaller.

Why would anyone use 30-40 brass that is not easily found for 303 brass which is everywhere? Perhaps you know a source for 30-40 brass?