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| Well crap...my idea may not work after all. I was hoping to drill a couple ports small, test, then redrill if needed. Based on the pin to hold the disk in, that doesn't appear possible. Now I need to do research or test via vented set screws in a gas block, then drill my disk. Unless there is a way to remove the pin than I'm not seeing... @Green0 am I missing something or do I have it right? |
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To remove the pin you would just have to remove the block. So maybe don’t pin the block until you like your settings? The disk pin is a slip fit, not a press fit. The guys in the build room had the blocks pinned for our testing and were nocking out the splined pin to change port sizes but I would not do it that way personally as it is just tougher. Make sure you read the manual pdf on the website. |
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Quoted: Sorry, I am still a little confused. Would it be possible to get a plate that has 1 large setting that is basically the barrels port size, a conventional suppressor hole, and LBP hole and maybe a something in between the two suppressed settings? I'm thinking 4 positions, wide open, two suppressed, and a fully closed for no action movement and really quiet. |
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Quoted: To remove the pin you would just have to remove the block. So maybe don't pin the block until you like your settings? The disk pin is a slip fit, not a press fit. The guys in the build room had the blocks pinned for our testing and were nocking out the splined pin to change port sizes but I would not do it that way personally as it is just tougher. Make sure you read the manual pdf on the website.  Prior to this thread I tried inserting the disk pin to see the fit and mine doesn't slide in at all. |
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There are two pins- one is splined for the barrel. The other is for the disc. The hole in the disk is supposed to be .126”, while the pin is .125”. There could possibly be a chamfer related burr? It’s a close fit. The splined pin for block to barrel is also 1/8” but larger at the three splines for press fitting or installation with a punch and hammer. The disc has to be oriented so the two large bullet notches are front and back to put the pin through the disc in assembly on the block. Otherwise the detent will fight assembly and make it a major struggle. |
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Quoted: There are two pins- one is splined for the barrel. The other is for the disc. The hole in the disk is supposed to be .126", while the pin is .125". There could possibly be a chamfer related burr? It's a close fit. The splined pin for block to barrel is also 1/8" but larger at the three splines for press fitting or installation with a punch and hammer. The disc has to be oriented so the two large bullet notches are front and back to put the pin through the disc in assembly on the block. Otherwise the detent will fight assembly and make it a major struggle. |
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Quoted: I'm thinking 4 positions, wide open, two suppressed, and a fully closed for no action movement and really quiet. |
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Quoted: Read all of that and understand. I'll check for burrs in the gas block tomorrow as I can't even get the disk pin to start into the top of the gas block. Quoted: Quoted: There are two pins- one is splined for the barrel. The other is for the disc. The hole in the disk is supposed to be .126", while the pin is .125". There could possibly be a chamfer related burr? It's a close fit. The splined pin for block to barrel is also 1/8" but larger at the three splines for press fitting or installation with a punch and hammer. The disc has to be oriented so the two large bullet notches are front and back to put the pin through the disc in assembly on the block. Otherwise the detent will fight assembly and make it a major struggle. ETA: The disk pin is a tight fit in the disk, but I can put it through by hand. SO, I tried he gas block again. I couldn't see any burrs, but it was hanging up. Pushed on the pin on my workbench and it popped in. Can then use a punch and push it all the way through with hand pressure. The top above the disk is tighter and requires me to push with a punch, but once past the disk slot it falls through the block from there. Excited to get it drilled and tested! |
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Quoted: IMHO, I wouldn't bother with a dedicated position for off. Just move it between positions if you want to do that. On top of that, last time I checked Griffin didn't have plate with no hole drilled in one of the 4 positions. As I posted before, I have had some scenarios where shutting the gas off completely would result in having to mortar the gun to get the spent case out. I know it happened with IMI Razor core 77Gr. I think it may have happened in some 300BLK scenarios as well but this is like 10+ years ago. I would imagine an .034 hole will not put enough gas to most Ar's to cycle the bolt carrier. I would also bet people who want to use a shut off, are using subsonic ammunition, and then it really won't move the BCG because the pressure will also be super low. But you are correct in that we didn't make any discs with no holes drilled in any of the positions, because we felt running an Ar15 like a bolt gun is less than ideal due to the lack of a mechanism for generating primary extraction, which in a bolt rifle is a camming action of the bolt that gives mechanical advantage to the initial extraction of the case from the walls of the chamber. The AR15 uses kinetic energy from a moving bolt and the carrier hits the cam pin and taps the bolt [and case] free of the chamber after it has unlocked the bolt by spinning it. That kinetic energy is kind of not there without velocity- hence "mortaring" to extract in the event of a failure to extract. |
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Got mine drilled and installed today. I went with .082 for normal and .067 for suppressed. This is for a 12" 6 ARC build. I'll open those if needed after testing, then likely do a step bigger on the other side for a dirty gun. Switching between normal and suppressed is easy but the clicks are solid. I did have to file down the tip of one side of my disk pin the get the gas tube in, but that took 10 seconds with a file. The disk BARELY clears a Geissele MK16 rail (this pic was difficult to get for some reason so it.osnt the best). Attached File Attached File Attached File Attached File |
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Maybe you picked up a burr when you drilled the hole, and that may have been your clearance issue? The rifle looks good. We didn't anticipate any fitting issues, but I guess I would think rubbing the part on a piece of 320 or higher grit sandpaper on a flat surface would be an ideal way to reduce the size. Is the barrel gas port larger than .082? |
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Quoted: Maybe you picked up a burr when you drilled the hole, and that may have been your clearance issue? The rifle looks good. We didn't anticipate any fitting issues, but I guess I would think rubbing the part on a piece of 320 or higher grit sandpaper on a flat surface would be an ideal way to reduce the size. Is the barrel gas port larger than .082? I am not 100% sure on the barrel's gas port size, but my .086 drill bit fits in and has a tiny bit of play. Centurion Arms advertises a .082 on their 12.5" 6 ARC so that is why I chose .082. This is a 1/2" shorter, so it's possible I'll have to open it up to .086. Hopefully not any bigger. |
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Oh I’m sorry I thought you meant you had to file the disc, not the pin. The pin must have been long that makes more sense. I was thinking how did the disc need to get filed? I was going to say if the hole in the barrel is .082” drilling the regulator hole bigger won’t do anything but if you have an .087 port that makes good sense in having a normal and adverse setting. |
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Quoted: Got mine drilled and installed today. I went with .082 for normal and .067 for suppressed. This is for a 12" 6 ARC build. I'll open those if needed after testing, then likely do a step bigger on the other side for a dirty gun. Switching between normal and suppressed is easy but the clicks are solid. I did have to file down the tip of one side of my disk pin the get the gas tube in, but that took 10 seconds with a file. The disk BARELY clears a Geissele MK16 rail (this pic was difficult to get for some reason so it.osnt the best). https://www.ar15.com/media/mediaFiles/57550/1000005604_jpg-3633804.JPG https://www.ar15.com/media/mediaFiles/57550/1000005605_jpg-3633805.JPG https://www.ar15.com/media/mediaFiles/57550/1000005606_jpg-3633806.JPG https://www.ar15.com/media/mediaFiles/57550/1000005611_jpg-3633807.JPG OCL Polonium Rainier 12" ultramatch 6 ARC CMC Enhanced 6 ARC BCG Geissele Super 42 spring with H2 buffer Griffin gen 2 SN-ACH Attached File Case on left was unsuppressed, case on right was suppressed. Attached File |
| I received mine yesterday and im excited to try it out, however I overlooked the fact that the 2 large holes are larger than any barrel port. This particular rifle is way overgassed unsuppressed with an H3 buffer. I was hoping the large hole would choke it down unsuppressed, but that isn't going to be the case. I guess ill need to order a DYO disk first. |
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So I finally got my adjustable gas block installed on a 12.5 in Ballistic Advantage Barrel with a .077" gas port. The gun has the Vltor A5 receiver extension. I did a quick crude measure of the two orifices on the plate and got about .055" and .077. The suppressor is an OCL Infinity with the non-vented 5.56 end cap. I used the dual lock EZ brake that came with my HRT suppressor. The ammo was Winchester white box 5.56. Starting off suppressed it wasn't cycling the action. I put in the lightest A5 buffer and the weakest spring that I brought with me. I lubed the F out of it and got it to cycle most of the time, but it would never lock back on the last round. I went home and pulled two pieces of tungsten out of the buffer so I ended up with just the 4 steel weights. It was locking back some of the time but after about 45 rounds it started failing to lock back. I shot it unsuppressed and gadzooks, with that brake, it was like an M-80 was going off at th end of the barrel. It did cycle reliably and ejection was about 4:30.This gun is intended to shoot suppressed only, so I'm good to go unsuppressed. So now I need to find the semi-auto carrier I have somewhere and see if that gets me where I need to be. Otherwise, I'll need to.open up the suppressed orifice.   ETA: I'll try my Gen 1 HRT on it tomorrow, it should be higher back pressure. |
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There should be two suppressed settings .055, and .059 on the conventional plate. The other holes should be .096”. The second set is used by spinning the plate 180degrees and using the same orientation of selection on the right sideof the block. The LBP plate holes are .07, and .078. As you are saying it locked half the time, maybe you should try bringing up the hole size that wasn’t working out .005” so if that was the .059 hole you could try .065 for it. |
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That's very helpful thank you I thought I had two holes at .055". I'll have to make sure I'm on the .059" hole. I'll head back to the range tomorrow or Monday. |
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From what you are describing I’m not sure one will fix that, but if you were on the side with the smaller hole it could make a difference. Depending on where you live one round in a mag and fired right down into the dirt will either result in bolt lock or not. Some places that might be something you can get away with. If you get bolt lock 3 times, odds are a setting works. |
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Quoted: From what you are describing I’m not sure one will fix that, but if you were on the side with the smaller hole it could make a difference. Depending on where you live one round in a mag and fired right down into the dirt will either result in bolt lock or not. Some places that might be something you can get away with. If you get bolt lock 3 times, odds are a setting works. What I found out yesterday is that shooting the same Winchester white box 5.56 it would not reliably cycle the action on either the .055" or .059" setting. On .055" it wouldn't even cycle the bolt leaving the spent round in the chamber. On .059" it would mostly generate double feeds. What I did find that on the two wide open (.096") settings it ejected at 4:30 to 5:00 and was 100% reliable. I thought that that .077" gas port on this Barrel would be way over gassed, but perhaps because it's a mid-length it won't work on the suppressed settings. At this point I'm just going to get a standard gas block and run it, I'll tune it with springs and buffer weights to get it where I need it to be but it's very close right now. Apparently that OCL Infinity is actually very low back pressure. I may try my old gen 1 HRT suppressor to see if it will work on the suppress settings, but I set this thing up to use the infinity so that's what I'm going to stick with. |
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Quoted: Any chance of a .630 gas block version? I have a dozen ARs and only two have a .750 gas block size, neither needing an adjustable.  I was excited about getting a couple of these until I saw .750 only.  I don't know why I always seem to be in the minority.  Id buy a bunch of them. |
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Quoted: Any chance of a .630 gas block version? I have a dozen ARs and only two have a .750 gas block size, neither needing an adjustable. I was excited about getting a couple of these until I saw .750 only. I don't know why I always seem to be in the minority. There are some that were made in the smaller diameter. I thought it was 5/8”- but whatever A1 pencil block diameter is. They should be available soon. |
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Quoted: Just installed this on a 12.5" Mid gas with an old Turbo K. Firing suppressed is now an enjoyable experience. After using this I think I just lost all interest in a Piston Upper. With Amphibian's other upgrades this thing is so controllable in FRT mode. Cool. Yeah piston is just heavier, with more poi shift when you change gas settings or add a can. |
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