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Posted: 12/29/2013 5:24:47 PM EDT
| I ordered a complete upper from Model 1 sales and specified a low pro gas block. The upper has a yhm free float rail. they installed the standard gas block on the inside of the rail, and another at the end of the rail near the end of the barrel. Ive never seen this. Is it still functional? The gas tube ends at the first gas block, but isnt there a gas port under the block so the gas travels back to the bolt? Wouldnt there also be a port for the other block? I havent been able to contact them so I havent shot the upper yet for fear a bunch of gas will come out of the front block. wth... help |
| Yup. dissipator upper. So, the front gas block is pointless unless it has a sight or is railed huh? Can I just remove it? Im not sure why I need a low pro front gas block if there is no gas going to it. Im not even sure why model 1 would offer it if it isnt needed. Hm. Ill try to get some pics but I think brad answered my question. |
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Quoted:
I'm willing to bet they built it that way, because that was the options he asked for. I'm not a huge fan of Model 1 Sales, but some people swear by them. X2 I just looked at the site and the Dissy uppers have the same option pull downs as the other uppers. Hey OP, did they send a "shaved" gas block under the handguard or a lo profile? Brad |
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The original dissapators were made by cutting 20" rifle gassed barrels to 16".
They were prone to short cycling in cold weather when the insufficient dwell time (the length of barrel between the gas block and the muzzle) combined with the decreased power of temperature sensitive ball powders resulted in gas pressures insufficient to cycle the action. Nowadays dissies are built with carbine or mid length 16" barrels with low profile gas blocks hidden under the h/g and a FSB that only functions as a sight at the rifle length gas position. This is how a proper dissapator is built, Joe |
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Quoted:
The original dissapators were made by cutting 20" rifle gassed barrels to 16". They were prone to short cycling in cold weather when the insufficient dwell time (the length of barrel between the gas block and the muzzle) combined with the decreased power of temperature sensitive ball powders resulted in gas pressures insufficient to cycle the action. Joe A friend of mine had a stainless 16" barrel that had a rifle length gas system. I'm not sure who built it, but it was a pain to get running. It would cycle my handloads but would sputter and spit on box loads. Tula.....FORGET IT! LOL Brad |
| Sounds like they went herp derp while building your dissy. A dissipator requires the use of a fsb to make any sense, otherwise there is no point in the second gas-block. The only exception to this is if the lo-pro gas-block was holding on a hand-guard retaining plate, but I don't know if that even works. |
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http://www.model1sales.com/images/products/udispre762.gif
the lower upper in the picture is what I purchased except instead of a railed block its low profile. When I ordered it I assumed i needed the low pro block to fit inside the free float rail. |
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Quoted:
the lower upper in the picture is what I purchased except instead of a railed block its low profile. When I ordered it I assumed i needed the low pro block to fit inside the free float rail. Yeah the front low pro is useless. You might as well take it off. |
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