Aqizithiuda wrote:United states of brazilian nations wrote:so people, turns out i really had screwed up with calculations. i made some other quick calculations, some rough estimates on compressed powder etc. and reached a result, i guess.
so, as this thing uses compressed powder, hot loads, i'll sure have to make its walls ticker, but whatsoever. i managed to get some good estimates while basing it around the 6.8 SPC that would be a very close counterpart to mine.
the result is here.i'm a ballistics illiterate so i really don't know how to "read" these numbers. for a STANAG-compatible, 5.56x45mm NATO based cartridge, is this performance good, acceptable, meh, sub-par or utter crap?
It's pretty decent round. What are the dimensions of the case and the projectile?
well, that's where it gets complicated: all my attempts to accurately calculate its case capacity have failed, and as such i had to take a shot in the dark and estimate it based in other rounds. then i decided to use compressed-powder hot loads in order to achieve decent muzzle velocity. again, i estimated this. i do know i'll have to make the walls ticker in order to stand the higher pressures, though.
here are the dimensions: (you'll notice that the case diameter is 0.4 mm bigger than the 5.56mm NATO's case, but it is such a small difference that i think it will still be able to be fed through STANAG magazines)
base and rim diameter: 10mm
rim tickness: 1mm
"straight" case part lenght (from the extractor groove to the shoulder base): 30mm
shoulder case part lenght: 5mm
shoulder base diameter: 10mm
shoulder top diameter: 8mm
neck lenght: 5mm
neck diameter: 8mm
overall case lenght: 41mm
bullet diameter: 7mm
bullet lenght: 25mm
moar info on boolit (WARNING: not-metric to avoid bugs with calculator)moar info on boolit, metrici decided to go with a lead core, yeah.
overall cartridge lenght: 57.40mm