Superalloy barrels

[lysander]

As I posted in the quoted link, the benefit of nitriding a barrel is removed if the nitrided layer of the bore must be removed to allow chrome plating (not uncluding the benefit of the outside of the barrel being nitrided).

My curiosity comes from whether the nitrided layer within the bore must be removed to allow chrome plating to begin with, or if something can be changed in either procedure to allow the to barrel finishes to be applied and have thier effects remain inact to additively applied.

You say that a barrel can be nitrided and then chrome plated, assuming the nitrided layer within the bore remains intact and the chrome plating applied over it, why, exactly, are the effects not cumulative or additive?

Your second pargraph in the post I quoted does not help me understand. I am not trying to be obtuse, but I do admit to having not read up on the subject in some time and being not as interested in the topic as I once was.


And no, I do not subscribe to the line of thinking that just because it's not being done that way that it means that it's already been tried, tested and found wanting. I need a bit more than that.

Well, the M256 is a smooth bore tube, so it is of no particular problem to machine them oversized to accommodate the additional thickness of chromium. Since nitriding adds no additional thickness, there is no reason to remove the nitrided surface in order to plate it.

As to why they don't use it I cannot give an answer, other than to offer these two choices, 1) all the major caliber gun manufacturers, BAe North America (formerly United Defense), General Dynamics (Saco), Alliant, Mesa and Watervliet Arsenal as well as all the small caliber barrel manufactures like Colt and FN are complete idiots; all willing to spend millions of dollars since the late 1970 on things like explosive tantalum cladding or plasma spray as alternatives instead of a relatively inexpensive and simple plating over nitride, or 2) there is some technical reason why it is not worth the effort. You can pick your favorite.

There are many reports on how to increase barrel life published by the USG out there free for the reading, there are also as many more that are not released to the public.