Chapter 1: The Sights on the M224 60 MM Mortar Systems
The M64A1 mortar sights is used on both the M224 60mm mortar and the M252 81mm Mortar system. The sights have tritium; peripheral devices used with it, and use mills to get an accurate sight setting.
The M64A1 was used on the 60mm mortar since its adoption in the year1982. In that time the unit has gone through little or no changes really. The unit works much like a compass in that it's fine and coarse deflection scales are like that of the mills scale on the compasses that the Marine Corp uses. The M64A1 has a set of vials that tell the Gunner and Assistant Gunner (A-Gunner) when the mortar system is level, the two vials are the cross level and elevation vials. With the vials being level the Gunner and A-Gunner use the elbow telescope to sight in on the M14 aiming posts. The elbow telescope has a 302 mills filed of vision with a 1.5 times magnification. There is16 parts to the M64A1 sight unit, they are as fallows.
1 Fine Deflection Scale
2 Coarse Deflection Scale
3 Fine Elevation Scale
4 Coarse Elevation Scale
5 Elevations Vile
6 Cross Level Vile
7 Deflection Knobs
8 Elevation Knobs
9 Deflection Locking Knobs
10 Elevation Locking Knobs
11 Locking Lever
12 Dove tail
13 Holder Assemblies
14 Eye shield
15 Elbow Telescope
16 Latching Lever
All of those parts with that addition of Tritium allow the Gunner and A-Gunner to get rounds down range to suppress, and obscure the enemy and light the battle filed, to allow the 0311's, 3031's and the 3051's to take charge of the battle field and take the enemy by storm.
Inside the M64A1 is a radioactive isotope called Tritium. The half life of Tritium is 12.32 years, after that time frame the sight unit can either be "re-flashed" or replaced. The easiest way is to bring it to the armory and get a new one. The reason why it can be re-fashed and once again glow is because the way the protons and neutrons are configured them easily fuses with light atoms that of witch are Ultra Violate rays (uv-rays.) Even though the Tritium is past its half life the glow will still be there after the re-flash but not as bright. The Tritium lights up 10 parts of the M64A1.
The M64A1 has a few peripheral devices to aid the Gunner and A-Gunner in their jobs. Those devices are the aforementioned M14 Aiming stakes. The M14's are used to lay the mortar in on its target. The other part that works with the M64 and the M14 is the M58 and M59 Night Aiming Devices. These devices glow green and orange. They are attached to the M14's to allow the Gunner and A-Gunner to see their directional and aiming posts out in the field. The last device the M64A1 uses is the M115 Bore sight. The M115 allows the Gunner to sight in his sight. The Bore sight true's the M64A1; the M115 will tell the Gunner how many mills off the M64A1 are off so that the proper adjustments can be made.
Lastly the M64A1 is a virtual compass if you will. The M64A1 uses mills to get a 6400 Mills view. Since mills are hard to get accurate on just one scale the M64 breaks them down in to two scales. There is the coarse and fine scale. The coarse deflection scale is 100 mill increments from 0 mills to 6400 mills. Then once you get the rough amount of mills you then go to the fine scale witch is broken down in to 10 mill increments, between every 10 mills is 9 hash marks to get your exact set of mills. The fine scale reads from 0 mills to 100 mills. With the coarse and fine scales on both the deflection and elevation it's only too easy to get your round on target as long as the Forward Observer (FO) and Fire Control Center (FDC) are doing their job.
M64/M64A1 Sight Unit
Chapter 2: Laying the Gun Line by Compass
The lay by compass method is one of the least preferred methods used to lay the gun line. Even though it is the least preferred it is used every...
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