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Old 07-09-2018, 10:17 PM
swaghauler swaghauler is offline
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Quote:
Originally Posted by StainlessSteelCynic View Post
I'm a little confused here. Are you saying the M576 does not hold 20 pellets of 00 buck because you can't fit 20 into a shotgun hull?
Yes, I am (see below). The original M576 round was made in two configurations. An "E1" version with 20 pellets of #4 Buckshot in a specially vented Sabot designed to release the pellets slowly when fired and an "E2" version which had 27 pellets (also #4 Buckshot) spread across the face of a different Sabot contained in the cartridge. The reason there is even a Sabot to contain the buckshot is due to the pressure needed to launch that payload at 880ft/sec. It comes dangerously close to the roughly 35,000 PSI limit that the original M79 and later M203 were designed to because the M79 and M203 originally had Aluminum barrels and later M203s composite metal barrels (whatever they were...extruded steel maybe). This meant that the M576 grenade has a "liner" inside it (for pressure management) and it then "expels" a Sabot containing the buckshot (to control the rate of pellet expansion). Since the Sabot in the "E1" variant (the "E2" was discontinued during the Vietnam War) clearly protrudes through the nose of the grenade, just by looking at the round it is obvious that the sabot is roughly 12 gauge in diameter. It is also SHORT in length. The M576 is one of the shortest 40mm rounds available. It, therefore, cannot hold 20 pellets of 00 by volume. It also cannot hold them by weight as the round weighs 0.25kg including casing, powder, sabot, and payload. Add to that the fact that the M576 has been in production since the late 60's, and hasn't changed its appearance leads me to believe it is STILL stuffed with #4 Buckshot.

I still hear about this 00 Buck loading and I want to believe that it was made because the M320 can take far more pressure but it would have to have a DIFFERENT designation from the M576 (which contains #4 Buck).
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