steel gas tube

[Frederick303]

I seem to recall when working on figuring out changes, there is a instruction to replace these tubes when the rifles come in for inspection or rework, but I forget the echelon maintenance level where that update was to occur.

In that same instruction was the order to change out the old buffer, with the heavier one, to replace the firing pin if it was the old pattern and replace the rear butt screw with one that had a drain hole. I seem to recall the heavy firing pin was expected to be found in M16 only, not M16E1 or M16A1 rifles.