My favorite example of this comes from an old story I heard from a retired state trooper.

The entire state police force was being issued new revolvers. The new wheel guns were the same model, just going from .38 special to .357 magnum. His boss met him and gave him the new revolver and some ammo. Said trooper immediately went to switch out with his old sidearm. The boss asked him to test it first. Out to the "range" on a deserted road for "practice" and the mainspring broke on the second shot. This was effectively a one shot weapon. The maker replaced the weapon, but it was good the lesson was learned in practice not in a shootout.

I have since seen several .38 revolvers that were issued in pilot survival vests that would not fire. Makes me wonder how many years those revolvers went flying in such shape.