Apparently to bolster this new barrel to end twisting when Grams
View here to own definitions of your own conditions included in this desk. Sources: American Rifleman, ily off Guns, Colt’s Creation Organization, Inc.
Rectangular LMG: Cumbersome square handguard used on the brand new M16A2 Machine gun so you’re able to release temperatures just like the efficiently and quickly that one can
1 – Colt based lots and lots of “bastardized” AR-15’s playing with various other straight down receivers nevertheless same design amount. Depending on the go out off manufacture it may features a keen A1 otherwise an enthusiastic A2 down person. There cannot be seemingly a definitive selection of which rifles provides which recipient, or whenever Colt first started playing with purely A2 receivers due to their AR-15’s.
HBAR: Heavier BARrel, Heavy Barrelled AR, Heavy Barrelled Automated Rifle, Hefty Barrel Violence Rifle .223: .223 Remington, 5.56 x 45 mm NATO cartridge 9x19mm: 9 mm Parabellum cartridge .twenty-two LR: .twenty-two Much time Rifle rimfire cartridge 1:7″: Rifling in the barrel twists clockwise, with anyone groove and work out an entire revolution most of the 7 (7) inches (178 mm). 1:9″: Rifling about barrel twists clockwise, which have anybody groove to make an entire trend all 9 (9) in (229 mm). 1:10″: Rifling regarding the barrel twists clockwise, which have anyone groove and then make a whole wave all 10 (10) ins (254 mm). 1:12″: Rifling throughout the barrel twists clockwise, which have anyone groove to make a whole revolution the several (12) ins (305 mm).
Standard: Totally new slim barrel style. Did not endure lengthened firing very well offering reduced precision. A2: After form of barrel that was tapered at the front eyes 
in order to thicken the latest started barrel. I.’s the reason used it once the a beneficial pry pub. HBAR: Latest style of barrel that’s the same density brand new enitre duration by way of, rather than just this new open section. Stands up so you’re able to heat well and provide best accuracy. HBAR stepped: The latest barrel towards the M4 carbine designed specifically that have an effective “step” so you’re able to accomodate the latest M203 grenade launcher. Straight: Slip ring retainer amongst the handguard as well as the top receiver you to definitely provides a level cylindrical figure. Usually discovered merely on the very early AR-15 and you can Meters-sixteen rifles with A1 upper receivers. Tapered: Slip ring retainer within handguard and the higher receiver you to definitely provides a slight conical profile. Applied to brand new AR-fifteen and you will M-16 rifles. Smooth triangular: The first handguard placed on very early AR-fifteen and you will Yards-sixteen rifles. Nevertheless aren’t viewed now, perhaps not applied to new rifles. The new handguard is an excellent smoothened triangle shape which have vent openings from the the big. Ribbed cylindrical: New handguard applied to all of the modern AR-15 and M-sixteen rifles. Cylindrical in lieu of triangular, it’s got vertical ribs along the whole duration of the handguard to own better traction. Vent openings was along the most useful and bottom. Ribbed shorty: Same as the newest Ribbed cylindrical handguard available on progressive AR-fifteen and Meters-sixteen rifles, this new shorty handguard changes simply when you are faster to help you accomodate faster barrel lengths. Simple cylindrical: Unique handguard discover simply towards the eight” barrel of one’s 9mm Design 633. It offers no ribs which can be simple along its entire length. Has numerous openings from the finest and you can base in order to accomodate special accessories such as for instance a vertical foregrip and you can carrying manage.
3-prong: Vietnam-time thumb suppressor having around three slits and you may an unbarred front end. Soon converted to closed-end after flowers apparently got trapped into the the fresh new prongs. Birdcage: Newer style of flash suppressor that has half a dozen spaces with an effective finalized front. Converted to A2-layout to get rid of dirt kickup when shooting. A2-style: Current Colt flash suppressor who may have five spaces (a few in order to either side, two diagonally right up, and another right up) and a shut front. The possible lack of gaps at the end of one’s suppressor avoids kicking up soil whenever shooting. Vortex: An incredibly efficient flash suppressor one removes the muzzle flash actually off short barrels. Typically four-pronged and step 1/2″ more than the 3-prong suppressor. Latest designs feel the prongs turned quite counterclockwise.