- Location
- Nova Scotia
They only break when you slap the #### out of them.
The GSG 16 modification thread
- Thread starter Danfizz
- Start date
But... isn't that part of the point of getting an MP5 clone? Slapping to chamber a round is a significant portion of the fun! A silly portion, but still fun.
- Location
- Nova Scotia
I slap mine, but I also have a wack of spares.
Did a bit more tinkering on the GSG-16 this afternoon. It bothered me that to field strip for light cleaning I had to have a small Allen key. Sure the key isn't heavy or bulky... but that's the thing, it's really easy to lose, or even if not that then annoying to have to dig for the right one when a proper gun field strips without tools. I'd already bought a pair of HK takedown pins from pcwgr1, which work great, so this was the obvious last step towards making it a tool-free field strip sort of gun.
So starting with a block of UHMW polyethylene I fashioned a new part. I'd picked up some scrap ends at Polymershapes years ago while buying some delrin rod. The pieces they gave me from the cut-offs bin were all 20mm thick, which it turns out is perfect for sliding into the GSG plastic shell. One less dimension for me to cut.
The critical thing is retention of the metal bolt stop block, which slides up into a cavity in the shell of the gun. By design this is held using a tiny nut captured between the two halves of the gun and a small bolt running into that through the retaining plate. Whatever replaced the bolt needed a couple of holes to allow easy reciprocation of the bolt spring guide rods, which come back quite a long way when pulling the cocking handle back. Lastly I wanted to be able to easily flick the metal block downwards without resorting to poking at it with a knife or whatever, so I added a little button to the bottom of the plate.
So I cut a block to these dimensions, based on careful measurements from the plate to the back of the shell, then inside the stock cap, then some fitting cuts with a low angle block plane...
The milled hollow between the guide holes for the rods is for a plastic screw head cap I had in my junk bins (just happened to fit the hole in the plate perfectly) with a little 10-24 threaded bolt set into it, the metal bolt stop plate tapped for that bolt which is installed with Loc-Tite. Not strictly necessary as a fingernail will usually pull the plate down, but this makes it easier.
Sitting in the gun it protrudes 5mm. Not critical, as even if it slid back and forth a little it would still do the job of retaining the metal bolt stop plate, but starting about 1.5mm long then trimming and testing seemed preferable to prevent any rattling. There's lots of room for a finger and thumb to grab the block for removal. I drilled the guide rod holes a bit oversized, as any friction there would interfere with operation. I'm pretty sure a block of wood would be just fine, or if you wanted to add some mass to the gun this would be a good place to put in a chunk of metal. But UHMW is very durable stuff and I have a bunch handy, so an obvious choice for me.
I've ordered a CYMA retractable stock to replace the original, as I don't like the somewhat flimsy appearance of the stock back end, and even with soldering iron stippling it seems less than ideal to stay on my shoulder. Something like the original MP5 sliding stock with rubber pad appeals to me, as do the metal rails, which apparently I'll need to trim on one side to allow ejection and perhaps modify to prevent it coming right out on extension. Hope the CYMA stock is an easy swap with this block in place, but if not it won't be too hard to make another block, now that I understand the dimensional requirements.
Just had my 14-year-old son, who is a moderate shooting enthusiast and hasn't shot the GSG-16 yet, take it apart for cleaning and put it together again. It was easy enough that he only needed slight help in dealing with the metal bolt stop plate, as getting it back in is a bit fussy until you've done it a couple of times. No other help offered nor asked for, so the procedure is beginner level simple.
So starting with a block of UHMW polyethylene I fashioned a new part. I'd picked up some scrap ends at Polymershapes years ago while buying some delrin rod. The pieces they gave me from the cut-offs bin were all 20mm thick, which it turns out is perfect for sliding into the GSG plastic shell. One less dimension for me to cut.
The critical thing is retention of the metal bolt stop block, which slides up into a cavity in the shell of the gun. By design this is held using a tiny nut captured between the two halves of the gun and a small bolt running into that through the retaining plate. Whatever replaced the bolt needed a couple of holes to allow easy reciprocation of the bolt spring guide rods, which come back quite a long way when pulling the cocking handle back. Lastly I wanted to be able to easily flick the metal block downwards without resorting to poking at it with a knife or whatever, so I added a little button to the bottom of the plate.
So I cut a block to these dimensions, based on careful measurements from the plate to the back of the shell, then inside the stock cap, then some fitting cuts with a low angle block plane...
The milled hollow between the guide holes for the rods is for a plastic screw head cap I had in my junk bins (just happened to fit the hole in the plate perfectly) with a little 10-24 threaded bolt set into it, the metal bolt stop plate tapped for that bolt which is installed with Loc-Tite. Not strictly necessary as a fingernail will usually pull the plate down, but this makes it easier.
Sitting in the gun it protrudes 5mm. Not critical, as even if it slid back and forth a little it would still do the job of retaining the metal bolt stop plate, but starting about 1.5mm long then trimming and testing seemed preferable to prevent any rattling. There's lots of room for a finger and thumb to grab the block for removal. I drilled the guide rod holes a bit oversized, as any friction there would interfere with operation. I'm pretty sure a block of wood would be just fine, or if you wanted to add some mass to the gun this would be a good place to put in a chunk of metal. But UHMW is very durable stuff and I have a bunch handy, so an obvious choice for me.
I've ordered a CYMA retractable stock to replace the original, as I don't like the somewhat flimsy appearance of the stock back end, and even with soldering iron stippling it seems less than ideal to stay on my shoulder. Something like the original MP5 sliding stock with rubber pad appeals to me, as do the metal rails, which apparently I'll need to trim on one side to allow ejection and perhaps modify to prevent it coming right out on extension. Hope the CYMA stock is an easy swap with this block in place, but if not it won't be too hard to make another block, now that I understand the dimensional requirements.
Just had my 14-year-old son, who is a moderate shooting enthusiast and hasn't shot the GSG-16 yet, take it apart for cleaning and put it together again. It was easy enough that he only needed slight help in dealing with the metal bolt stop plate, as getting it back in is a bit fussy until you've done it a couple of times. No other help offered nor asked for, so the procedure is beginner level simple.
DropTheBomb
Member
- Location
- Calgary, Alberta
Decided to pick up one of the Magpul MP5 grips since my local shop decided to bring some in, fits great but needs a bit of modding so decided to share my experience.
If anyone wants one they are here: https://store.theshootingcentre.com/magpul-sl-hand-guard-hk94-mp5-black
In terms of fitment there will be 2 spots that need to be dremeled for the grip to fit, first is the barrel lug stabilization tab and second the rear top of the grip to clear the receiver.
The barrel lug will be in the shape of an upside down L,you will essentially shave off/cut off the top portion of the lug so its flat. You dont want to completely cut it off smooth as it aids in making the grip solid to the gun.
Next is shaving the rear sides. You will need to shave off a 3mm x 19mm section on each side, mark it off with pencil and go nice and slow. Do better than I did, and test fit as you go.
You can even cut a little less than 3mm wide to get a tighter fit, remember you can always cut more but never add on.
NOTE: If you find the grip is not slipping on in place after cutting the sides then its possible you need to trim the barrel lug just a bit more, but in my experience if that top portion is gone then its a perfect fit.
And there you have it! The grip is super solid and has zero play, and look awesome!
If anyone wants one they are here: https://store.theshootingcentre.com/magpul-sl-hand-guard-hk94-mp5-black
In terms of fitment there will be 2 spots that need to be dremeled for the grip to fit, first is the barrel lug stabilization tab and second the rear top of the grip to clear the receiver.
The barrel lug will be in the shape of an upside down L,you will essentially shave off/cut off the top portion of the lug so its flat. You dont want to completely cut it off smooth as it aids in making the grip solid to the gun.
Next is shaving the rear sides. You will need to shave off a 3mm x 19mm section on each side, mark it off with pencil and go nice and slow. Do better than I did, and test fit as you go.
You can even cut a little less than 3mm wide to get a tighter fit, remember you can always cut more but never add on.
NOTE: If you find the grip is not slipping on in place after cutting the sides then its possible you need to trim the barrel lug just a bit more, but in my experience if that top portion is gone then its a perfect fit.
And there you have it! The grip is super solid and has zero play, and look awesome!
What's that paddle you have installed on yours, DropTheBomb? The knurling looks neat.
I did some more rocket surgery on mine yesterday. The redundant front rail up top bothered me, as did the open sights which I'll never use - at 58, though my eyesight is somewhat improved after a couple of years on a better diet, I don't think open sights are in my future. Dots are usable again thanks to my eyesight improving significantly since stopping being a vegetarian for most of my life, so for the moment the Holosun 403R gold dot sight actually has me hitting the bull pretty good with this thing. But I may have to swap in a compact scope at some point, like I have on my Chiappa Little Badger.
Anyway, I was guessing that cutting off the rail and sanding it down to a rounded profile would make the outer edges of the plastic too thin. And sure enough that was the case. Actually broke through slightly for a couple of inches towards the receiver end. But no matter because I had a plan. Digging through my scrap aluminum tubing box I found an old tripod leg tube, very thin aluminum, perfectly suited to slide over the resulting thin plastic surround for the cocking piston. Once I had the rail sawn off and filed and sanded round, I just did some work with paper and pencil to trace the left-side cocking slot, transferred that to the aluminum tube, and went to work with drill and Dremel with a carbide carving bit to shape the slot. Slotted the bottom to slide over the remaining lower part of the front plastic, then with everything carefully test fitted, smeared the inside of the tube (except the last 5/8" where I needed it free for dismantling - so I smeared beeswax over the part where I didn't want anything to stick) and the outside of the plastic with JB Weld steel filled epoxy. Slid it into place, cleaned away the excess, waited a while (impatiently), then after some hours took a file and Dremel to the front end and the cocking slot to finish up the fit.
Now the plastic and aluminum are integrated and quite strong, cocking paddle functions fine, and there's no excess rail nor recess to fill with a 'rail delete' strip, just a nice clean forend to complement the aluminum I put over the barrel. A few coats of VHT engine paint with a hot air gun waved over it between coats and everything blends in more or less. Now just waiting for shipment of a CYMA sliding stock with rubber pad and I guess that'll be all the mods for mine.
I did some more rocket surgery on mine yesterday. The redundant front rail up top bothered me, as did the open sights which I'll never use - at 58, though my eyesight is somewhat improved after a couple of years on a better diet, I don't think open sights are in my future. Dots are usable again thanks to my eyesight improving significantly since stopping being a vegetarian for most of my life, so for the moment the Holosun 403R gold dot sight actually has me hitting the bull pretty good with this thing. But I may have to swap in a compact scope at some point, like I have on my Chiappa Little Badger.
Anyway, I was guessing that cutting off the rail and sanding it down to a rounded profile would make the outer edges of the plastic too thin. And sure enough that was the case. Actually broke through slightly for a couple of inches towards the receiver end. But no matter because I had a plan. Digging through my scrap aluminum tubing box I found an old tripod leg tube, very thin aluminum, perfectly suited to slide over the resulting thin plastic surround for the cocking piston. Once I had the rail sawn off and filed and sanded round, I just did some work with paper and pencil to trace the left-side cocking slot, transferred that to the aluminum tube, and went to work with drill and Dremel with a carbide carving bit to shape the slot. Slotted the bottom to slide over the remaining lower part of the front plastic, then with everything carefully test fitted, smeared the inside of the tube (except the last 5/8" where I needed it free for dismantling - so I smeared beeswax over the part where I didn't want anything to stick) and the outside of the plastic with JB Weld steel filled epoxy. Slid it into place, cleaned away the excess, waited a while (impatiently), then after some hours took a file and Dremel to the front end and the cocking slot to finish up the fit.
Now the plastic and aluminum are integrated and quite strong, cocking paddle functions fine, and there's no excess rail nor recess to fill with a 'rail delete' strip, just a nice clean forend to complement the aluminum I put over the barrel. A few coats of VHT engine paint with a hot air gun waved over it between coats and everything blends in more or less. Now just waiting for shipment of a CYMA sliding stock with rubber pad and I guess that'll be all the mods for mine.
DropTheBomb
Member
- Location
- Calgary, Alberta
The mag release or charging handle? Either or they both come with the GSG-5 conversion kit
Charging handle, sorry. Okay, so that's part of the conversion kit, thanks for the information.
Thanks so much for sharing all of this info DropTheBomp. Ordered one last week and it arrived / got installed today, you saved me a lot of tears and time.
On mine I was a bit to aggressive with my first cut on the barrel lug so if I squeeze really hard I can get it to flex slightly vertically after mounting. I’m not that bothered though since overall it fits very well! Cheers!
My apologies if this has already been pointed out before but I haven't been able to find it (large thread!) however has anyone with a caliper posted the specs of the push pins required?
Looking on aliexpress I did come across some Tippman push pins that are considerably cheaper than the HK ones.
https://www.aliexpress.com/i/32989769583.html
Looking on aliexpress I did come across some Tippman push pins that are considerably cheaper than the HK ones.
https://www.aliexpress.com/i/32989769583.html
- Location
- Nova Scotia
Decided to pick up one of the Magpul MP5 grips since my local shop decided to bring some in, fits great but needs a bit of modding so decided to share my experience.
If anyone wants one they are here: https://store.theshootingcentre.com/magpul-sl-hand-guard-hk94-mp5-black
In terms of fitment there will be 2 spots that need to be dremeled for the grip to fit, first is the barrel lug stabilization tab and second the rear top of the grip to clear the receiver.
The barrel lug will be in the shape of an upside down L,you will essentially shave off/cut off the top portion of the lug so its flat. You dont want to completely cut it off smooth as it aids in making the grip solid to the gun.
Next is shaving the rear sides. You will need to shave off a 3mm x 19mm section on each side, mark it off with pencil and go nice and slow. Do better than I did, and test fit as you go.
You can even cut a little less than 3mm wide to get a tighter fit, remember you can always cut more but never add on.
NOTE: If you find the grip is not slipping on in place after cutting the sides then its possible you need to trim the barrel lug just a bit more, but in my experience if that top portion is gone then its a perfect fit.
And there you have it! The grip is super solid and has zero play, and look awesome!
Looks nice, How is that new rail delete holding out?
Got mine from that seller in Surrey, forgetting the CGN username at the moment... Anyway, mine have the skinny spring clip, not the nice fat one the genuine HK pins supposedly have (according to that guy near the Skytrain who posts most of the GSG-16 stuff on YouTube). Looks like the gun is generally built on metric dimensions.
My pins measure just a hair under 6mm - the vernier caliper tells me 5.9mm, I guess 0.1mm for ease of insertion. Length from the inner face of the head to the inner edge of the retaining spring bump measures 27mm. Of course there's likely to be a bit of play one way or the other with the spring clip bump. Though the two pins I have are identical and interchangeable, the one retaining the lower has about 1.5mm of play back and forth. Totally secure, it can just be pushed back and forth a bit. The stock retaining hole is a snug fit for the pin there.
DropTheBomb
Member
- Location
- Calgary, Alberta
Took it out so far 3 times, appears to be holding zero. I am thinking about utilizing one of the barrel nuts found on the original rail for extra stability.
Just about have the ABS set up all ready, so ill be making a prototype from that!
- Location
- Nova Scotia
Sweet... I'll be waiting with some money...
DropTheBomb
Member
- Location
- Calgary, Alberta
The lug you cut off essentially mates with the bottom of the area of where the receiver/barrel/chamber area is screwed together. The more you shave off the more up and down play there will be if im understanding what youre implying.
And no, this is a new design of my upper rail filler since it seems many people still want a rail segment on the top of their guns. Going through trials to make sure it holds optics nice and firm
Another little modification of my GSG-16 today. The long, rather muddy feeling trigger pull kept bothering me, but I didn't want to dismantle the whole fire control group and poke around to see what could be done internally so I'd held off until today. Finally realized I didn't have to take it apart, as I tested (using spent casings to protect the chamber from the firing pin - though it seems ATI did a good job of spacing this as it doesn't quite touch the barrel on firing empty) the trigger reset and found that a considerable amount of slop could be adjusted out in front by just adding a shim between trigger and frame. After establishing a range of working shim thicknesses, but wanting more adjustibility than just gluing in a shim, I decided to drill and tap the metal trigger for a bolt. 1/8" hole, 10-32 tap, and I was off to the races! Of course without dismantling I had to get at it a different way... so I bored a hole in the front of the trigger guard for access. Not pretty, but no real harm done, and if I like I can always patch it up with some JB Weld and a bit of black dye powder to match. But this gives really easy access for an Allen key should I ever want to adjust it.
The round head bolt rests against the front of the slot in the frame, and at about 4mm elevation from the upper trigger face it reduces my total trigger pull to just 7mm, slightly over 1/4", without reducing pull weight at all. Feels much more crisp as the mod has taken out about 8mm of pre-travel, leaving only about 4mm of pull before it breaks and 3mm after that. Adjusting the bolt slightly further out locks up the reset, so that seems to be about the safe limit. Dab of Loc-tite on the threads and it'll stay where I put it. The bolt head is just above where my finger engages so I don't even feel it.
Still waiting on a package full of 6-32 socket machine screws with which to replace most of the flimsy factory screws. I really dislike Torx screws, especially when made of such mushy steel. And allegedly my CYMA collapsing stock is on a FedEx truck today for delivery. Love it when a plan comes together.
The round head bolt rests against the front of the slot in the frame, and at about 4mm elevation from the upper trigger face it reduces my total trigger pull to just 7mm, slightly over 1/4", without reducing pull weight at all. Feels much more crisp as the mod has taken out about 8mm of pre-travel, leaving only about 4mm of pull before it breaks and 3mm after that. Adjusting the bolt slightly further out locks up the reset, so that seems to be about the safe limit. Dab of Loc-tite on the threads and it'll stay where I put it. The bolt head is just above where my finger engages so I don't even feel it.
Still waiting on a package full of 6-32 socket machine screws with which to replace most of the flimsy factory screws. I really dislike Torx screws, especially when made of such mushy steel. And allegedly my CYMA collapsing stock is on a FedEx truck today for delivery. Love it when a plan comes together.
- Location
- Nova Scotia
According to Dlask, they removed the GSG blueline edt adjustable trigger screw, because it caused issues. So don't be alarmed if it does.
Personally I don't mind the trigger, It is not a precsion gun by a long stretch.
Personally I don't mind the trigger, It is not a precsion gun by a long stretch.
Yeah, watched GNutzguy install the trigger bolt. Wasn't impressed by how that worked. He says the addition of the correct bolt dropped pressure from 4.8lbs to 3.8lbs, while maintaining the same length of travel and general feel. So that mod changes it from a slightly heavy long, mushy, uneven trigger pull which breaks somewhere near the end of travel, to the same thing but about 20% easier to pull. Not at all what I wanted. My mod reduces travel such that it's a short pull to the break, not enough time to notice it being mushy. And so far as I can tell, function isn't at risk so long as I allow at least 1/2 bolt turn past where trigger reset fails. I'm getting clean and consistent function with more than half the trigger travel removed. It's not as sweet as the trigger on my Pardini K12, but that would be asking a lot of a cheap plastic .22lr replica, considering the K12 has one of the finest triggers ever made.
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My CYMA stock got here today. Tried to like it. Really wanted to like it. But nope, it's going into a drawer as a spare, in case the original one breaks. Here's why:
- More than 1/2" of side-to-side waggle when fully extended, with no obvious way to fix this.
- Plastic seems cheap compared to original, probably no glass fibres in it, looks and feels likely to crack in handling.
- The rubber butt cap was lifting off the plastic base in several areas, not properly moulded at all, popped off very easily making me thing it'd also do that in use, while shooting, if I wasn't careful; so I've used some silicone 'Aquaseal' adhesive and a bunch of masking tape and within a couple of days once that's cured it'll be on there solidly.
- Right-side aluminum arm covers about 20% of the ejection port. I knew this before ordering (again thanks to one of Gnutzguy's videos - he's providing a great service with his videos), but still it bothers me. Not quite enough to cut away any metal... because then it would likely wobble even more when fully extended. Besides this, the rails pop right out the back with no mechanical restraint. If I ever use this stock I'll drill and tap for a small bolt with a large head in the front of the left-side rail so the bolt head stops against the rear cap.
- The locking mechanism wobbles all over the place when handling the toggle, more than 1/8" in every direction. Flimsy as heck! Feels like something I'd worry about on a squirt gun, never mind a firearm. Looks like it's held together with some epoxy inside. Pathetic.
I'd offer to sell it, but I paid too much to a California-based company for the thing, shipping costing as much as the stock, so I'd never get close to my money back. Better to glue on the rubber pad, maybe mod it so it doesn't fly apart on extension, then give some thought to how I might firm up the extended stock so it's not a rattling, wobbling, very silly thing as it is now. If I eventually resolve the problems I may throw it on... but it would take a lot of fixes. And I doubt the original one is going to break. Thing works great. Well enough that I've now chopped off the silly spare mag holding area in the buttstock and filled it, covering a bonded in place plastic element with some silicone (Sugru) putty.
