problem with certain garand enbloc clips

[PaulN]

....... PPU commercial which we are talking about at 885 mps is 164 fps faster than recommended M1 load.

I could (easily) be wrong but suspect that slight variations in bullet muzzle velocity isn't as big a consideration (for the gas operated Garand) as is the pressure curve of the powder burn.

(in the 'food-for-thought' category)

If we took a M1 Garand and removed the gas plug, so that all the gases exited out-the-front and did not actuate the piston, then we would have temporarily converted the rifle to a manually operated bolt action. In this situation significantly higher bullet muzzle velocity would likely eventually lead to reduced barrel life but I think that's all. 164 fps is less than 10 percent greater than typical military loading so I would not expect there to be a significant difference.

Now the matter of the gas pressure curve ..... that is something that I don't believe we have any way of actually measuring short of instrumenting a barrel with a bank of piezo-electric stress transducers (I just checked and nope - don't have any in my junk box).

I think (boy I'm really going-out-on-a-limb a lot in this conversation) that it would be relatively safe to equip a Garand with one of the 'variable-leakage' (my name for 'em) plugs that are available on-the-market and adjust it so that there is just enough pressure to allow the rifle to cycle properly (eject the spent cartridge and load the next).

Hmmm .....I wonder if it would be feasable to put a small magnet on the operating rod within the Garand and have a small coil to sense the induced Voltage as the mechanism cycles ? We could compare the Voltage curve (I believe proportional to ds/dt but I'd better think about this) of a 'reference round' (try to get a 'real-GI round') and then measure the curve generated when firing a Prvi Partizen round (and an American Eagle for good-measure). As long as the curves were roughly the same as that produced by the 'reference round' then we could feel confident that the Garand's mechanism wasn't being unduely-exercised by the PPU rounds.

- Paul