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Posted: 12/6/2014 3:33:13 PM EDT
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No, not some friendly girl I never met before ...
Being a newly badged adept of WECSOG, I'm working on my FCG and I came across a situation to ask the hive about. I inherited multiple issues with this gun. The grip screw—normally a slot head for a Colt Sporter, yes?—was replaced with an allen screw, don't ask me why. But when I pulled off the grip, I found a second allen screw "underneath" it, protruding into the FCG pocket. I figured a previous owner had bubba'd replacing the grip screw, drilled into the pocket, and then filled the hole with a second allen screw just to cover the mistake, or I dunno, maybe stop hot gas from coming down through the grip?  It wasn't causing a problem, so I just left it, not broke don't fix.
But I was having holy hell replacing the lower parts. Dropped in the trigger assembly, could not then insert the selector. Come to find out, the second allen screw is sticking up so far into the pocket that it was pushing the trigger tail up enough to interfere with inserting the selector. I thought I'd just pull that damn second allen screw out, live with a "minor" gas leak through the grip ... and then I wondered if it would really be a minor leak, or none, or a disaster, and I thought of the hive ... but the penny had not dropped yet ... So I started to remove the second allen screw ... had backed it off just a little, figured I'd try again to install trigger & selector, and suddenly the trigger tail was no problem, selector slipped right. And then the penny actually dropped, and I remembered that among this gun's "issues" is a trigger with absolutely imperceptible creep, a practical zero, just put enough weight on it (about 7.5 pounds) and it fires. Maybe the previous owner installed this second allen screw to allow adjustment of trigger travel?
Anybody heard of this before? Should I keep this mod and learn how to use it? I was ready to pull it out, or mill off the pocket-side of the screw, but then I thought, wait ... ask ARFCOM ... 
p.s. Is it just me or does that damn screw look like HAL 9000. |
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I have installed those in dozens of rifles for friends, as well as polishing and buffing the sear surfaces, and replacing the springs with JP springs for reduced weight.
If you re-install it, a few thoughts. Cock the hammer, turn in the screw until it trips the hammer. Back up one turn. This is important, you are using the screw to " pre-pull" the trigger, starting the trigger pulling off the hammer sear. Shortening the sear contact. Going too far is dangerous. I always " bump test" after installing by dropping the rifle butt first ( collapse your stock first, if you have that type) onto a padded surface (like carpet) from 6-10inches, repeatedly, until I am satisfied that there is ample engagement to prevent accidental discharge. Lock tight it to make it stay put. It's a great way to get rid of the long gravel road of milspec triggers. This is advice from an unknown internet home gunsmith, so take it for what it's worth. You should have the skills and confidence to tinker with it, if you don't feel comfortable, just remove it. Here's a link to a thread in " Build it yourself" that details this and other trigger mods. Link |
| Caution and care when polishing factory trigger and hammer sear surfaces. They are just case hardened, some very shallow. Don't get over zealous stoning them or you can get into the softer steel then the trigger goes south, sometimes very quickly (250ish rounds). |
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To adjust the 1/4 x 28 set screw correctly, cock the hammer back, set the selector to safe, then while shoving the selector detent pin up since you have the grip off to postion the selector in the correct movement postion, move the selector back and forth fromfrom safe to fire while screwing the set screw up. The set screw is set correctly (with a dab of 242 blue loctite on the top of the set screw threads) when you feel just a slight resistance of the selector moving back into the safe position.
What the set screw is doing it taking out the free play of the trigger at rest, to be pulled against the selector set to safe. P.S. To do this set screw mod, the pistol grip bolt has to be shortened. |
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Okay I read all those links. This is great stuff. I'm saving those pages and will re-read for retention.
I'm not really that picky about trigger action. I just want the thing to work. I'm not a competitor or anything, just a schmoe with BRD, or "unknown internet home gunsmith" if you prefer, sounds a skosh better doesn't it. I just want to learn this gun inside & out, and this is a wonderful new discovery. I'm proud I guessed right for a change and actually figured the thing out, though I had to come here for validation (and probably always will). |
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Learning ...
The taphole for the grip screw is specced to go all the way through to the pocket anyway. Didn't know that. But for Joebob's "trigger adjuster" to install with no machining (at least drill & tap), the taphole would have to go through already. Gas leak is not an issue because whether original "solid" grip screw, or Joebob's two-part nested "trigger adjuster" screws, or two separate "fitty cen" homejob screws like I have, however it's configured, the taphole for the grip screw is sealed by the screw(s) in it. To get a gas leak, you'd have to have a single hollow screw like Joebob's grip screw without the smaller nested screw. I wonder, theoretically, would it even be an issue? Gas flow through the BCG is open into the upper receiver, and therefore into the lower receiver, and therefore out through any hole that might exist in the FCG pocket, yes? If you had a Joebob's trigger adjuster, and you somehow lost the smaller nested screw, you'd have a leak, yes? Would the gun suffer undergassing cycling problems, do you think? Theoretically. Maybe by the time the gas has vented all the way down into the pocket and out the grip, the BCG would have cycled all the way back to its max travel in the buffer anyway, so it'd make no difference? I'm fuzzy on timing issues. |
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Quoted:
once the gas key/gas tube break contact. gas pressure is no longer a factor in the cycle. Yup, you are overthinking the gas issue; AR's are no where near gas tight, lot's of places to see daylight through them between the upper, lower, charging handle, pins. It's a quick pulse on the BCG gas key, then it's over with. No need to worry about " leaks". |
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once the gas key/gas tube break contact. gas pressure is no longer a factor in the cycle. That really makes perfect sense. Cheers. lot's of places to see daylight through them between the upper, lower, charging handle, pins. Yeh I was wondering about that too. So that clears it up. Mine has a little play between upper/lower, but I guess it is just an aesthetic issue at this point. |
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... a little play between upper/lower, but I guess it is just an aesthetic issue at this point. |
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Quoted:
Why would anyone do this when there are so many good trigger choices available? Because with a set of JP reduced power springs for $10 you can make a very nice, clean, 4-5 lb trigger with almost zero creep and a fast reset. For those of us on a budget, it's a great option, especially if you have multiple rifles. $100-200 for a drop in trigger package is a lot of reloading supplies for me. Besides, I like to tinker with my guns and learn how to make things work better myself, not buy other peoples expertise. |
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Quoted:
Because with a set of JP reduced power springs for $10 you can make a very nice, clean, 4-5 lb trigger with almost zero creep and a fast reset. For those of us on a budget, it's a great option, especially if you have multiple rifles. $100-200 for a drop in trigger package is a lot of reloading supplies for me. Besides, I like to tinker with my guns and learn how to make things work better myself, not buy other peoples expertise. Quoted:
Quoted:
Why would anyone do this when there are so many good trigger choices available? Because with a set of JP reduced power springs for $10 you can make a very nice, clean, 4-5 lb trigger with almost zero creep and a fast reset. For those of us on a budget, it's a great option, especially if you have multiple rifles. $100-200 for a drop in trigger package is a lot of reloading supplies for me. Besides, I like to tinker with my guns and learn how to make things work better myself, not buy other peoples expertise. That's all fine and dandy I guess but it doesn't look like a modification you could trust to not fail at some point and it appears to damage the lower in the process. |
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That's all fine and dandy I guess but it doesn't look like a modification you could trust to not fail at some point and it appears to damage the lower in the process. Quoted:
Quoted:
Quoted:
Why would anyone do this when there are so many good trigger choices available? Because with a set of JP reduced power springs for $10 you can make a very nice, clean, 4-5 lb trigger with almost zero creep and a fast reset. For those of us on a budget, it's a great option, especially if you have multiple rifles. $100-200 for a drop in trigger package is a lot of reloading supplies for me. Besides, I like to tinker with my guns and learn how to make things work better myself, not buy other peoples expertise. That's all fine and dandy I guess but it doesn't look like a modification you could trust to not fail at some point and it appears to damage the lower in the process. That's not my experience. I have many thousands of rounds downrange on multiple rifles without issue, and have dozens of other rifles that I have done for friends and acquaintances with out issue or complaint. It's simple and reliable if done correctly. If by chance they parts did wear and become unreliable, the replacements are $40. I have not heard of anyone having to replace their FCG due to this mod. I also don't get where you think this " damages" the lower. . It's completely reversible.
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That's not my experience. I have many thousands of rounds downrange on multiple rifles without issue, and have dozens of other rifles that I have done for friends and acquaintances with out issue or complaint. It's simple and reliable if done correctly. If by chance they parts did wear and become unreliable, the replacements are $40. I have not heard of anyone having to replace their FCG due to this mod. I also don't get where you think this " damages" the lower. . It's completely reversible.
Quoted:
Quoted:
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Quoted:
Why would anyone do this when there are so many good trigger choices available? Because with a set of JP reduced power springs for $10 you can make a very nice, clean, 4-5 lb trigger with almost zero creep and a fast reset. For those of us on a budget, it's a great option, especially if you have multiple rifles. $100-200 for a drop in trigger package is a lot of reloading supplies for me. Besides, I like to tinker with my guns and learn how to make things work better myself, not buy other peoples expertise. That's all fine and dandy I guess but it doesn't look like a modification you could trust to not fail at some point and it appears to damage the lower in the process. That's not my experience. I have many thousands of rounds downrange on multiple rifles without issue, and have dozens of other rifles that I have done for friends and acquaintances with out issue or complaint. It's simple and reliable if done correctly. If by chance they parts did wear and become unreliable, the replacements are $40. I have not heard of anyone having to replace their FCG due to this mod. I also don't get where you think this " damages" the lower. . It's completely reversible.
The picture in the first post shows staking around the pistol grip screw hole inside the lower to stop the set screw from turning = damage. |
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