Originally Posted by LostintheOzone

Eventually the M4 will be phased out of inventory just like all other US military weapons. Having been in the military I can tell you that sooner or later a better mousetrap comes along and once tested and deemed better it will be adopted throughout the military.

Too many examples exist as proof. Once the M9 was determined superior to the 1911, it didn't take long for the Army to mothball all 1911's. I have one that set in a crate in warehouse for maybe 40 years. It wasn't issued to anyone after it was rebuilt, just stored in a crate with 80,000 other 1911's. The reason was logistical and economical. The military had a new cartridge just like they do now with their new rifle. They will not support two rifles using different cartridges any more than they will support two pistols.The math just doesn't work for the bean counters. Does anyone see any M9's in the military inventory these days? Nope. Even though it uses the same cartridge. Other factors determine the longevity, like parts and replacement. My understanding is the SIG costs the military less than $200 per pistol.

I went to boot camp in the Navy in 67. We didn't have any M-16's to train with, but we were probably the last few companies who didn't. Every service had those by 69, four years after the Army got them.

My guess is the M4 isn't long for this world for any military training or issue. I'll say 5 years and it will be gone, just like the M9.

Don't look for any barrels full of mil surp M4's for cheap either. They will all go into the recycle bin just like the M-14's.