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Posted: 5/18/2008 11:29:15 AM EDT
Please suggest a lightweight upper with the following:
I'm looking to replace a Colt HBAR II upper with the lightest possible configuration while maintaining the above requirements. Thanks |
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The barrel is where most of the difference will be. As suggested, CMMG has lightweight barrels, but they don't offer twist rates other than 1:7 and 1:12. The Bushmaster Superlight 16" I have is a 1:9. And, of course, you can always get a Colt 6520 barrel, but that's costly. Les Baer has a lightweight upper receiver with no forward assist, but with a port door and brass deflector and DPMS has two models of upper receivers with no forward assist, brass deflector or port door, but they have non-standard top rail heighths. I think Fulton Armory also has a lightweight upper receiver. Another avenue to a lightweight upper would be to get a 9mm upper receiver and have Adco drill a gas tube hole in it. And you'll want to look at free floating frontends instead of standard handguards. |
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Double Star Lightweight 16" barrel from Brownells I prefer CMMG over anything other brand but they don't offer this barrel in 1/9. Unless I overlooked something it's 1/7 or 1/12 from them in this config unfortunately. A flat top upper is a flat top upper with regard to weight IMO. The Double Star is 1/9 & the A1 profile. |
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Halloran: You said "lightest possible". You might check out the following. You can order a specially built Carbon-15 M4 style flat-top upper using their 16" Superlight barrel. Bushmaster SuperLight 16" Barrel Assembly Look for Part No: A BBL-16SLA. Price: $235.00. This is a chrome-lined 1:9 twist 16" barrel. Contour is .670" to .565" under handguards, .625" under sightbase, and to .570" at the muzzle - similar to original Vietnam era A1 barrel profile. Assembly includes Bayonet Lug, Threaded Muzzle, A2 Birdcage Flash Suppressor, Handguards, Gas Tube, and Delta Ring Kit. Carbon-15 Flat Top Upper Receiver Look for Part No: AZ15747. Price: $160.00. This upper does not use a forward assist or ejection port cover, so you save a little more weight and $$. You need to call or email Customer Service to do this special order. They're nice guys though and it will be a super-easy process: Email: [email protected] Phone: Customer Service: 1-800-883-6229 The Carbon-15 M4 type flat top upper combined with their SuperLight 16" barrel is probably the lightest Ultralight flat top you can get. Oh, you may need this item: Colt Large Hole Lower to M4 Type Small Hole Upper Offset Pin Look for Part No: NES-06. Price: $6.50 I think you'll need one of these if you have an older Colt Match HBAR lower using a screw-on, large-hold forward assembly pin. Note: This packages uses M4 feed ramps on both the upper receiver and the barrel's receiver extension so you're GTG. It is also compatible with their new gas piston conversion kit... I hope this helps 
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My 1/9 Bushmaster Superlight shoots 1.5" at 100 with M855 and an EOTech. I'm sure handloads would drop that number considerably. The rifle is exceptionally light and balances very well. |
I have a bushie superlight as well. It is terrific. Yesterday I shot a group that was about .5" creating one hole w/ my aimpoint CompML2 at 30 yards semi supported using 55 gr Privi Partisan. That would bear out to 87GN's 1.5" at 100 so I think these barrels are accurate enough. |
Chamber dimensoion and crown have more to do with accuracy than what diameter and length the barrel is. Sloppy chambers on bolt guns or a piss poor crown will kill accuracy. |
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