Have a 43 Spanish roller carbine, it chamber casts a super long neck. I have 2.250 formed brass which is at least .4 short to fill the neck area. The cases will headspace correct on rim at this point so stretching fresh case heads is not an issue on first firing. The .4 jump to the throat is the issue.
Anybody else encounter this? I just cant believe they (arsenal) would cut a chamber with a neck that long! Planning on shooting this week to fireform my tiny necked brass. Aside from expected horrible accuracy, sending the lyman 385gr bullet jumping that far with BP, any issues? Its so long I couldn't even make a breech seater to help. Id still have .25 inch of airspace above the case mouth.

And of course the bore is exceptional not warranting more drastic rework.

Thanks in advance

I shot an Argentine extensively.  I did a chamber cast, and my recollection is that the correct case length was at least 2.55".  I purchased stretched basic .44 brass from Buffalo Arms and formed it.  Worked well, and looked like either a long-neck .44-77 or short body .44-90.  Shot well, too.

FYI, all these rifles have a rim recess of ~0.090".  The basic brass I purchased had 0.060" (IIRC) rims, so I experienced stretching and separation within the first 2 firings.  I send them back to BA and they bumped the rim to ~0.088", solving that problem.  Not sure whether they could still supply the basic brass or the thick rims-they show .44-90 cases with various rim thicknesses, but none that thick.  In any case, measure your rim recess before calling them to make certain what you need.

If you can't find the correct rims, you can make a spacer that slides over the cartridge and provides the additional thickness.  You just need the proper thickness of stock.

Clarence

I used the Lyman, but with the long neck to match the chamber, it was seated just short of the rifling.

So loaded, I believe it would have shot into 1-1/2 MOA if I had put target sights on the rifle.  I could get 3 or 4 of 5 into that size group.

Clarence