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Posted: 4/22/2016 12:13:11 AM EDT
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Is the Israeli IMI M855 loaded to actual M855 pressure? Does it have the same quality checks?
I would like to put up some more M855 but I DO NOT want the Federal XM stuff. I want real M855 not factory seconds only guaranteed to .223 SAAMI pressure. While the Federal may be fine, usually, it is a fact that the XM line are the rejects from the DOD orders and are not necessarily loaded to spec. Hence I am looking for a source of the real stuff, is the IMI what I am looking for? Also what is the "Razor Core" stuff? I know IMI makes a knockoff of MK262 but I don't remember anything about "Razor Ccore." |
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I can't speak for every lot, but every lot I've ever used was loaded to M855 pressures. Quoted:
I've no doubt, but isit loaded to actual M855 spec or is it just a .223 spec of some flavor with an SS109 projectile? Quoted:
Quoted:
IMI good stuff I've no doubt, but isit loaded to actual M855 spec or is it just a .223 spec of some flavor with an SS109 projectile? |
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The US mil-spec for M855 (MIL-C-63989C [Amendment 4]) states that the average velocity of the cartridges “shall be 3,020 feet per second (fps) plus or minus 40 fps at 78 feet from the muzzle of the weapon. The standard deviation of the velocity shall not exceed 40 fps.” This specification is for a 20” barrel and depending upon variables equates to a muzzle velocity of approximately 3105 FPS (plus or minus 40 FPS.) 
As an aside, after reading the above specification, some of you may be wondering, “Why 78 feet from the muzzle?” The answer to that question is that this specification is simply an historical hold-over from the days when “circuit” chronographs (e.g. Le Boulenge Chronograph and the Aberdeen Chronograph) were used at Aberdeen Proving Ground, Frankford Arsenal and Springfield Armory. These types of chronographs required a significant distance between their first and second screens to produce accurate results. As an example, when using the Boulenge Chronograph, the first screen of the chronograph was placed 3 feet in front of the muzzle and the second screen was placed 150 feet beyond the first screen. For those of you who might not be aware of the following fact; chronographs determine the velocity of the bullet at a point that is midway between the first and the second screen (i.e. not at the location of the first screen). Therefore, with the above spacing, the velocity of the bullet is determined for a point that is 75 feet from the first screen. So, add the three feet (from the muzzle to the first screen) to the 75 feet (the midway point of the screens) to obtain the “78 feet from the muzzle” distance. 
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