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Posted: 1/18/2014 6:33:56 PM EDT
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Seems straight forward, right? Slide the gas block on the barrel, line up the hole in the barrel with the hole in the gas block, screw it down, and 'voila' your gas block is installed.
Eh, not quite so fast there, Baba Looey... I'm installing a Geissele Super Gas Block on a Black Hole 18" barrel. The barrel has one dimple on the underside for a set screw type gas block. But I have some questions I can't figure out... 1. Is the distance from the dimple to the back edge of the mounting surface standard? Mine appears to be about 0.25". I can't get a steel rule inside the gas block but the distance from the back edge of the gas block to the set screw appears to be about the same. True? Or does it vary from manufacturer to manufacturer? 2. Is the relationship between the placement of the dimple on the underside of the barrel to the port on the top of the barrel standardized? How do I know if I utilize the existing dimple that the gas port will accurately line up the port on the barrel? and finally... 3. How in the hell am I supposed to make sure that the hole in barrel lines up correctly with the hole in the gas block when I can't see or reach either one? Thanks in advance -K2 |
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Unless you bought your stuff from china, The back set screw the one that sets in the dimple will set it up correct for you.
"2. Is the relationship between the placement of the dimple on the underside of the barrel to the port on the top of the barrel standardized?" Yes |
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Quoted:
is that .300 inches? Quoted:
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the gas port is approximately .300 from the barrel shoulder....the set screw hole is where the gas port is drilled into the portion of the gas block between the barrel hole and the tube hole.....they have a relationship....  is that .300 inches? That gap is for a handguard cap. And yes that is inches. |
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Quoted:
the gas port is approximately .300 from the barrel shoulder....the set screw hole is where the gas port is drilled into the portion of the gas block between the barrel hole and the tube hole.....they have a relationship.... At least I can understand that kind of relationship!
Thanks everyone for the info. -K2 |
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Quoted:
is that .300 inches? Quoted:
Quoted:
the gas port is approximately .300 from the barrel shoulder....the set screw hole is where the gas port is drilled into the portion of the gas block between the barrel hole and the tube hole.....they have a relationship.... is that .300 inches? Normally expressed as 300 thousandths. 
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Quoted:
Normally expressed as 300 thousandths. Quoted:
Quoted:
Quoted:
the gas port is approximately .300 from the barrel shoulder....the set screw hole is where the gas port is drilled into the portion of the gas block between the barrel hole and the tube hole.....they have a relationship.... is that .300 inches? Normally expressed as 300 thousandths. Never seem a mechanical drawing with the word "thousandths" attached to every dimension. Absolutely nothing wrong with ".300" posted above |
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Quoted:
Never seem a mechanical drawing with the word "thousandths" attached to every dimension. Absolutely nothing wrong with ".300" posted above Quoted:
Quoted:
Quoted:
Quoted:
the gas port is approximately .300 from the barrel shoulder....the set screw hole is where the gas port is drilled into the portion of the gas block between the barrel hole and the tube hole.....they have a relationship.... is that .300 inches? Normally expressed as 300 thousandths. Never seem a mechanical drawing with the word "thousandths" attached to every dimension. Absolutely nothing wrong with ".300" posted above True. I'm an old T&D Maker. But now days, one never knows. Hell half the people I run into are lucky if they can read a scale And they work in hardware stores.
But when one guy in the shop talks to another he'll say want's something machined to 300 thousandths!
We know what we are talking about. |
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