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15 Cards in this Set
- Front
- Back
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What is recoil?
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The force that propels the round towards the target drives the gun to the rear.
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The interior of the cannon is divided into what three zones?
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1.Zone 1-the chamber region. Begins at the breech face to 18 3/4 inches into the cannon
2.Zone 2-tapered zone. Starts at 18 3/4 in to 22 into the cannon. 3.Zone 3-bore.the bore starts at 22 in and is the rest of the intrerior of the cannon. |
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What occurs at the rear of the chambered region?
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rear oturation occurs.
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What does the tapered zone do?
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it is the trainsition between the chambered zone and the bore, which guides the projectile into the bore, and compress the obturator on the projectile resulting in forward obturation.
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The exterior of the cannon is divided into what three areas?
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1. Breech Recess area
2. External machined surfaces 3. Thermal shrouds |
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The breech recess area is what?
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the threaded end of the cannon that is inserted into the breech ring. This are contains the interrupted buttress threads
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What are the external machined surfaces?
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This area contains the surfaces of the cannon that are machined for fitting extarnal components such as the MRS, and the bore evacuator as well as the surfaces that interact with the recoils system.
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What are the thermal shrouds?
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Form fitting alluminum sleeves encase the exterior of the gune tube and aid in the even distribution of heat around the gun tube.
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What is the operation of the chamber and bore?
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1. initial detonation and cartridge case combustion
2. Rear obturation 3. forward obturation 4. Projectile forward movement 5. Bore evacuator pressurization 6. Shot exit 7. Automatic breech opening 8. Extraction and ejection begin 9. Residueal gases evacuated. |
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The bore evacuator does what?
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Aids in removing spent porpellant gases from the gun tube.
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The M256A1 gun tube uses what?
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Eccentric pressure scavenging system
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Describe the bore evacuator?
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the bore evacuator is a chamber like device, located at about the center of the gune tube.
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Why is the bore evacuator eccentric?
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Because the bore evacuator and the gun tube do not share a common center.
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Inside the bore evacuator there are what?
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5 evenly spaced holes drilled at a 30 degree angle towards the muzzle.
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The bore evacuator is tested at the factory to sustain what?
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225 PSI +/- 5PSI
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