XM21

“Semi-automatic marksman rifle based on the M14 with 3-9x scope”

— in-game description

- Description here -

History

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The XM21 was experimental sniper rifle based on the M14 rifle.

Modifications:

The XM21 was modified from standard M14s to make them more accurate. The barrels were inspected to higher quality standards than regular M14s and installed with as little headspace as possible. The flash suppressors were specially machined to be as accurate as possible. The gas cylinder, barrel band, and piston were polished to reduce carbon build up. The gas cylinders were attached to the front barrel band, and the point at which they were finger tight was indexed to 6 o'clock. The triggers were changed to a 4 1/2 - 4 3/4 pound pull. The operating spring guide was replaced with a tapered one that made the spring compress uniformly. The fire selector shaft was welded in place to prevent automatic fire. All moving parts and points of contact were smoothed. The iron sights were accurized, with the front sight blade being made 0.062 inches wide, smaller than the standard M14 front sight. The rear sight was made 1/2 MOA instead of the standard 1 MOA. The rifles were glass bedded without the stock liner in modified stocks that wouldn't warp. The stocks had all moisture removed by baking them in a vaccum oven at 300 °F for 1 hour. Then they were impregnated with resin epoxy and baked for 1 hour at 100 psi of pressure. The stocks were then cured in an oven for 3 days. The rifles were given Adjustable Ranging Telescopes, which was a Redfield Accu-range 3-9x40mm scope, the same as used on the M40, but with a different reticle, mounted in a cam system that pivoted the scope forward as the zoom was increased, automatically adjusting the scope to take bullet drop in to effect at range.

Use in Vietnam:

The first 10 XM21s were field tested in Vietnam in 1967. The 9th Infantry Division were some of the first to use the XM21 in 1968. In 1969 large scale (approximately 50 per week) production commenced, and over 1,300 XM21 rifles were used in Vietnam, mainly by US Army snipers.

Suppressors:

The XM21 was sometimes used with a M14SS-1 suppressor made by SONICS (Later shortly changed to "Environmental Industries" and then "Military Armament Company" on December 21st, 1970.), who also made suppressors for the M16, M2HB, MAC-10, and other guns. The M14SS-1 was not officially adopted, but was purchases by the US Army and US Navy. 40 of the first M14SS-1 suppressors were field tested by the 9th ID in 1969. The suppressors were used by snipers of the 9th ID, 25th ID, 173rd Airborne Brigade, MACV SOG, and some Marines, among other users. The suppressors were sometimes used in conjunction with sub sonic ammo which didn't break the sound barrier, meaning no "crack" noise, and / or shutting off the gas tube, effectively making the rifle bolt action, to prevent the loud noise of the action cycling. Sometimes snipers would fire a round, which would burn off the oxygen in the barrel and suppressor, then tape off the suppressor preventing the gases from escaping. This means the next shot would have no oxygen, and so would not create a muzzle flash, useful in low light shooting.

Weapon Specifications

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XM21

- Full name here -

Ammunition
Ammo Type
Rounds Per Magazine	20+1 Rounds
Magazines	4 Magazines
Weight Per Magazine	0.4 kg / 0.88 lbs
Handling
Weight	5.27 kg / 11.62 lbs
Features	3-9× Redfield Scope Attachable Bayonet
Firemodes	Semi-Automatic
Recoil	Vertical: 700 Horizontal: 250
Spread (MOA)	1
Length	1118 mm
Melee Reach	1680 mm
Damage
Instant-hit Damage	160
Damage Value	745 147 (subsonic)
Energy Impulse	429
Penetration Depth	17
Ballistic Coefficient	0.24
Velocity	765 m/s 340 m/s (subsonic)

- Full name here -

Ammunition
Ammo Type
Rounds Per Magazine
Magazines
Handling
Weight
Firemodes
Rate of Fire
Recoil	Vertical: Horizontal:
Spread (MOA)
Length
Melee Reach
Damage
Instant-hit Damage
Damage Value
Energy Impulse
Penetration Depth
Ballistic Coefficient
Velocity