9mm case lengths highly variable?

[WarPig1976]

Nobody is saying fireing .380 in a .9mm is a good idea. What the OP is concerned with is his average case length for his .9mm cases .745 which is .009 under trim to length for .9mm. Will he see some blow by? Probably, does it matter? No it does not, Nobody is arguing your point Villiers,,he has already learned too lite of a charge can cause blow by and malfuction,, in the reloading world it simply is not common practice to concern oneself with straight walled pistol case length. What we do worry about is "c.o.a.l" cartridge overall length and charge weight, seating the bullet too deep can cause pressure spikes and blow the firearm up in your hand but that's off subject.
I don't want to confuse the OP, I can remember being in his shoes.