本帖最后由 lixiaoyong 于 2017-5-18 15:21 编辑
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那个AB39应该是5.56的型号，另外 .264 USA, .260 Remington这2款6.5mm子弹动能都上2700j了，特别是264 usa，只需要16.7英寸的枪管
3. Infantry Rifle
The Marine Corps is interested in rifles that incorporate technologies that are applicable to current and future battlefields. The Marine Corps is interested in a rifle that is guided by the following specific requirements:
– Upgrade package (URG + fire control group) or complete rifle with enhanced M27 like capability and features
– Free floated handguard 13” for use with 14.5” or longer barrel, 9.5” for use with 10.3/10.5” barrel. Accepts current authorized attachments (i.e., PEQ15/16, lights, etc.). System maintains accuracy and precision through all positons and means of support (free floated) be it sling, barricade, sandbag, etc.
– 14.5” barrel option, with 24,000 round life with AB49 – 2 MOA precision threshold, 1 MOA precision objective for majority of barrel life (Mean radius) (Army Capability Based Assessment requirements).
– Barrel may include low profile gas block but may not use taper pin
– Installation when using a barrel cartridge (i.e., barrel with gas block and barrel nut preinstalled) should take no more than 10 minutes threshold, 5 minutes objective (2nd echelon maintenance)
– Bolt carrier group optimized for M855A1 use with Picatinny Durable Solid Lubricant coating or any similar variations thereof
– Rail must maintain rigidity and alignment (to within 10 MOA) with the rifle’s zeroed point of aim when external pressures (up to 20 pounds) are applied 11” forward of the receiver (accounting for various means of supporting the weapon and weight of existing attachments and aiming devices)
– Rail must include continuous 1913 Picatinny rail at the 12 o’clock position with no interruption from the receiver rail to the handguard rail (semi-monolithic). Must include anti rotation features, may integrate into upper receiver.
– Rail must have integral forward 1913 Picatinny rail sections at the 3, 6, and 9 o’clock of 2-3” in length. Remainder of rail shall be M-LOK (like on SURG and ASR) at 3, 6, and 9 o’clock. Other surfaces may include holes/cutouts for air circulation and weight reduction.
– Rail must be field strippable in a manner similar to the M27 with captured bolts
– The rail may include a steel, or 7075-T6 aluminum barrel nut, but it must be non indexing in nature
– Rail must accept heat resistant rail covers of a similar nature and material to those found the M27
– Ability to fire AB39, .264 USA, .260 Remington, M80A1, etc.
– Modular bolt/barrel/magazine & magazine insert conversion packages for caliber changes (compatibility with A059, AB49, AB57, Mk255 Mod 0, etc) and optimized for respective caliber, charge, burn rate, and pressure curve (barrel threads can be 1/2X28 or 5/8X24)
– Novel approaches to lightweight rifle and ammunition
– Ambidextrous bolt catch and non-reciprocating charging handle
– Reversible magazine release and selector
– Adjustable length of pull stock, integral storage for spare bolt and QD sling attachment points
– Upper receiver will arrive with modular rail mounted sling attachment point
– Pistol grip sized for a 5th-95th percentile Marine
– Handguard sized 11-13” consideration to accessory use (lights, lasers, etc)
– Minimum mass cycling components to create no higher G-load than unsuppressed M110 SASS when fired
– High use of corrosion resistant alloys, coatings or treatments
– System deliberately built to perform at optimal level while suppressed – must divert gasses away from the shooter’s eye
– Bolt and barrel life greater than 15,000 rounds with no more than 200 FPS velocity loss
– Entire system serviceable at no higher than 2nd echelon maintenance level
– Coating or surface treatment in coyote brown in order to not stand out visually in combat environment, and desired reduction in IR signature.