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Old 10-30-2007, 10:34 AM
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Part II
Quote:
Further Clarification... (Longer than it needed to be!)
Posted By: Dick Culver <culver@jouster.com>
Date: Wednesday, 21 August 2002, at 1:05 p.m.
In Response To: Re: COPPER JACKETS, STEEL JACKETS, ARMOR PIERCING & BOAT-TAILED BULLETS! (mhb)
Further clarification...
MHB has touched on the salient points of the jacketing material, but the "tin" added to the Lubaloy and Gilding Metal was (supposedly - I'm not a practicing metallurgist) done to harden the (gilding metal) jacket material, or at least that was the theory. Pure copper jackets had been tried but at the muzzle velocity(s) associated with the .30-'06 the copper jacket was deemed to be too soft and prone to strip in the rifling, hence the addition of the nickel in the .30 caliber bullets, both the Krag and the Springfield/RIA. As he points out the 2000-fps gave little or no cupro-nickel metal fouling, but the "ought-six" at 2700-fps was another kettle of fish. Gilding metal, originally a combination of copper and zinc was still considered too soft to prevent stripping in the rifling (according to both Whelen and Hatcher - I'll have to take their word for it as I've never tested such).
The gilding metal composition (copper and zinc) was still thought to be too soft for the high velocities of the "New Springfield" and it wasn't until the innovation of the Lubaloy (Remington) bullet (1922) that (the "improved" composition of) gilding metal (with tin added) was considered to be satisfactory. The composition of the "new" gilding metal bullet (used in the M1 Ball) was essentially identical to the Remington offering. I'm not conversant enough with the actual machinations of the U.S. Government Arsenal(s) to know if the bullet compositions were arrived at unilaterally or some arrangement was made with Remington - I'm sure there is some documentation out there somewhere. The overall result is that it worked regardless of how they arrived at the final "formula"...
As anyone who has read Hatcher's Notebook can tell you, the "Tin Can Ammunition" was a very interesting solution to the cupro-nickel fouling problem and was apparently arrived at by noting that the French had been using strips of tin (tin-foil?) in their artillery cases. This turned out to be a nightmare in small arms cartridge loading, so tin-plating the bullet was a brainstorm by Major T. Whelen (himself an old time competitive rifle shooter and Distinguished Marksman) who was put in charge of solving the metal fouling problem at Frankford Arsenal. In 1921 Whelen's solution was what has come to be called "Tin-Can Ammunition"…
A tin plated bullet solved the fouling problem alright, but a slight hitch developed - the bullets apparently cold soldered themselves in the brass cases. When testing the ammo, it seems that pulling the bullets of the ammunition (usually taking 50-60 lbs.) suddenly came up with a bullet pull from 300-600 lbs. Uppsss! This was compounded by the contrary nature of the target shooter who had been using a field expedient of greasing his bullets using a grease called "Moblilubricant" or even Cosmoline. My Dad shooting at Perry in 1919, 1920 and 1921, said the standard Marine Corps solution (prior to the Tin-Can Ammo) was to use Cosmoline since it had the advantage of being free (a real advantage when a private was drawing $21 per month). The idea seemed to be that the lubrication of the bullet cut down on the coefficient of friction, and thus cut down on the fouling left by the cupro-nickel jackets. Unfortunately grease is NOT compressible, and when the chamber was coated with the Cosmoline/Mobilubricant (the result of dipping entire 5-shot stripper clips in a typewriter can full of grease for rapid fire), the case (neck - or over the long haul during a match, for that matter the entire case) could not expand and release the "cold soldered" bullet from the case neck, thus raising the chamber pressure to possible disastrous levels. Try as they might, they simply couldn't break the habits of (all) the competitors, and at least one projectile was found downrange still (cold) soldered to the case neck. The case neck too, had rifling marks on it - chamber pressure? Gawd only knows, but following the matches (although the ammo set some new records for accuracy) the so called "Tin Can Ammo" was withdrawn from service.
The 1922 National Match Ammo used the "new" Gilding Metal jacket and had a 6 degree boat-tail setting the stage for the later M1 Ball (that used a 9-degree boat-tailed bullet) that was our standard service load until the beginnings of WWII.
What does the "boat-tail" configuration do for a projectile? Well, in a wind tunnel study you'd find that the "slip stream" passing over a flat-based bullet will create what amounts to a vertical "shock wave" off the tail end of the projectile. The boat-tailed configuration allows the "slip stream" to pass over the base of the bullet in a much more streamlined fashion and cuts down on the perturbation(s) effecting bullet flight. In essence, it is simply a more efficient (streamlined) bullet, giving greater range and long-ranged accuracy. It certainly did that alright, as the maximum range was extended from approximately 3500-yds for the M1906 Ball (and later the M2 Ball, a clone of the original M1906 except for bullet composition), to (again approximately) 5500-yards for the M1 Ball - these figures are off the top of my head, so don't hold me to their exactness, but you get the idea.
As MBH has pointed out this was OK until the mobilization for WWII when many of the ranges for the National Guard folks simply didn't have the safety backdrop necessary for the M1 Ball. Ed Clancy has also pointed out that they had run into some manufacturing problems with the M1 Ball almost simultaneously with the decision to come up with a more "range friendly" round, the need for indirect (reverse slope) machine gun fire being taken over by the .50 caliber and tactical air. In this case it became a which came first, the chicken or the egg…
A case could be made for stopping the manufacture of the M1 Ball because of manufacturing difficulties, OR it could be said that the manufacturing difficulties simply got the ordnance folks off their posteriors to solve the "short-range" (National Guard?) problem with the long range M1 Ball? Who knows for sure? It may have been a simultaneous decision that complimented each cause. My personal cut is that both Hatcher's contention that a shorter ranged round was mandated, and Clancy's research indicating some latent manufacturing difficulties sort of came together at a most convenient time. Obviously the manufacturing difficulties could have been cured as they were by 1957 for the then new FA Match Round (essentially the same as the old M1 Ball Ammunition), but since the lighter bullet answered a need and solved a (different) problem the entire thing became academic. EVERYTHING became academic once the decision was made to issue the M2 AP Round as the standard combat round for WWII and the thing sorta' slipped into the mists of history. As a matter of personal observation, I started shooting the M1 in the Marine Corps in 1953 and never saw a single round of M2 Ball ammo until I got into the match shooting program in the late 1950s. We always qualified with AP and even shot the Division Matches with the stuff. Until we finally hung up the M1 in the mid 1960s, the Corps was still shooting M2 AP as its standard round.
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