Hi everyone!

This might be more engineering than gunsmithing but this forum seemed the most appropriate for my question.

I like to fool around with Matlab and wrote some programs that calculate the dynamics of automatic firearms. As I'm an engineer and gunsmith, some of these programs are for actual design and some are just for fun. The newest one is for the HK G3/MP5 series.

All of these programs work fine and give realistic values but I still can't find values for the energy loss in the recoil springs and buffer. An old US Army design guide concerning automatic firearms uses values of 0.5 (half of the kinetic energy is lost during bolt travel) but this seems a bit high to me.

I could'nt find anything online, maybe because English is not my first language and I used the wrong search words. My engineering books also did'nt cover this subject.

So, does anyone have maybe empirical data concerning the internal friction of recoil springs and buffers or maybe some formulas? Search suggestions are also very welcome.

Thanks!

Thanks! Hysteresis might be exactly what I needed, could'nt come up with a good translation by myself. I have the dynamic friction allready in the model, this is a lot easier to find the right values for.

I guess the 0.5 value from the design guide was to include friction and hysteresis in one approximate value.