GBB Gun/Mag How To
Regular maintenance, fix leaks, improve efficiency, etc
A Few Words About Grease And Oil
Regular Gun Maintenance
Gas Mag Parts
Oiling Your Magazine
more to come
This is just a general "how to fix and maintain your gas gun/mag" post, because I know some people know how to do this and some don't, so to save those who don't having to buy replacements, here it is. This will be a work in progress as I add more stuff to it. The gun and magazine in the photos are an HFC P226 and a KJW P226 replacement mag. This mag is supposed to be compatible with KJW, HFC, TM, and other P226 GBB pistols, but, as I found when I tried to use it, it performs rather poorly in anything but a KJW. Until I performed the mods below, that is. This should apply to any similar guns and mags, e.g. any 226 blowback, many 9mm models, etc. Some of the features/options may be different, but you should be able to get the gist of it from the pictures and figure it out on your own gun.
A Few Words About Grease And Oil
White lithium grease has to be the slipperiest substance on earth. However, the debate rages on as to whether it damages o-rings or not, and my thing is: why take a chance? I'm not going to argue with anyone about whether or not lithium grese does damage seals, I don't care about your experince with lithium grease, the fact is, silicone doesn't damage seals. So, on any parts that don't touch seals, especially where you have serious metal-on-metal friction, lithium grease would, without a doubt, be the best lubricant for the job. However, you'll notice that I don't use it in this guide, and there are 3 reasons for that. First, some of the parts I'm greasing come into contact with rubber or plastic parts, and I just don't see the advantage of using a grease that might possibly in some way degrade them, when pure silicone grease won't. Second, even on parts that don't come into direct contact with rubber or plastic parts, grease spreads, that's it's job, and why use 2 incompatible greases for a single job, when one does the job just fine? And three, white lithium grease is white. My gun is black. That means when a little bit of grease manages to work its way out of the gun onto the outer surface, or when you fire and the slide racks back and you see the outer barrel, you'll see white grease on my gun. It's perfect for AEG gearboxes, but in a GBB gun, I'll stick to silicone. The kind I use for these kinds of applications is made for use in pool filters and pumps, and is actually sold as a seal conditoner and lubricant. You should be able to find it at the hardware store, or at any pool supply store.
To apply it, I use my finger, or a toothpick, or a popsicle stick, or whatever is handy and will reach the places I need to reach. Don't use anything hard or sharp like metal, because you might scratch something that shouldn't be scratched. Anything like wood or plastic should work fine.
As for oil, I usually use a silicone/teflon mixture that comes in an areosol can by DuPont, called, coincidentally enough, "DuPont Teflon/Silicone Lubricant." It's safe for rubber and plastic, it's nice and thin but provides good lubrication, and it's inexpensive. I use it below for lubing the mag seals, but I use it for cleaning barrels too.
Depending on your gun, it may break down differently, this is how the GBB P226 breaks down.
With the slide locked back and the magazine removed, flip the breakdown lever
With the lever down, pull the slide forward until it seperates from the body
Remove the barrel parts from the slide so they can be maintained
I'll leave opening the hopup and cleaning the barrel for another day or another guide. Suffice to say, you should clean your barrel regularly, and you need to remove the hopup before you do it so that you don't get your hopup bucking oily. And yes, I teflon modded my pistol's hopup.
Now turn your attention back to the slide, so we can remove the loading nozzle assembly. There are three screws, one in the side of the slide, the others through the top, which actually also hold on the sight on this pistol.
Take out the loading nozzle and put a thin coat of heavy grease all over the outside. Then put quite a bit of grease on the little "rails" on the side of the nozzle. Spread it better then the picture, but get enough on there that it will get on the parts inside the assembly.
I also put a thin layer of grease on the cylinder cup, just for a better seal and less friction. Put the cup back on and the nozzle into the assembly, but before you screw it all back into the slide, work it back and forth in the mount where it will slide when the gun is fired. If you pull it back out, the grease should've spread out and gotten on the inside of the assembly. If there are any large chunks of grease still on it, wipe them off. You want a thin layer covering pretty much the whole nozzle. Then screw the loading nozzle assembly back into the slide.
Next, put grease in the slide rails. The rule here is, any place that shows paint wear gets grease. If you have a silver slide, use your best judgement, and grease any place where metal rubs on metal. I tend to grease liberally, and then remove whatever is left over.
I also grease the outer barrel, where it rubs on the slide. Again, look for paint wear to know where it rubs.
With that done, put the slide back on the pistol, and without a mag in, rack the slide quickly and repeatedly 8-10 times. There should be no stiffness or rough spots that you have to pull through. There may be some grease that has worked it's way out of the seams, wipe it off and do it again until no more grease works its way out. Your gun is now greased. That does it for regular maintenance. Once a year or so you will want to get into the trigger parts and regrease those, but they don't move nearly as much as the slide, so they shouldn't wear nearly as much as the slide parts.
After I've done this, I like to put two mags through it, for several reasons. The first I actually learned a long time ago as a musician: if you show up for the gig and your amp don't work, you don't get to play.
You don't want to wait until you need
it to fire to find out you forgot to put the hooziewhatsit back in the thingamajig. So make sure everything works, and hopefully better than before you lubed it. Second, grease spreads and thins and works it's way out of seams. You also put oil in your magazine, which is going to blow out in the first few shots of the first mag. It may get oil on your hopup rubber. So, put a couple mags through the gun, make sure it's working, make sure you've blown any excess oil out of the mag and pushed any excess grease out of the slide and nozzle assembly, and wipe it down well before you put it away.
I'm going to do two things at once here, because I wanted to replace my hopup bucking, which will require me to retape it, so I'll show you both at once.
I'm going to replace the stock bucking with a Nineball bucking, which is as simple as pulling the old one off and putting the new one on. When you put it on, make sure you have the little ridge on the inside of the bucking lined up with the notch in the barrel.
Run a single wrap of teflon tape around the entire bucking and end of the barrel, starting from the bucking side, until it's far enough to show outside of the hopup unit when it's reassembled. If you have trouble reassembling the hopup, like the barrel is too thick, that means you used too much tape. Remove it all and try again. A single wrap means each wrap around covers half of the previous wrap, so the next wrap covers the half that isn't covered yet, etc. You should end up with exactly 2 layers of teflon tape, one overlapping the other halfway, except at the very ends, where you'll get an extra half-wrap where you straightened out the tape. The important part is the very middle, where the bucking steps down to the barrel, that is what you are trying to seal.
Here you can see the teflon tape showing outside the reassembled hopup unit
This serves a couple of purposes. One is to keep gas from escaping from the back end of the hopup bucking, where it is just sitting on the barrel. Pressure from the hopup unit should
keep that from happening, but ACM tolerances being what they are, gas escapes. A decent bucking will get a better seal and keep gas from escaping out the front, and some teflon tape will keep gas from escaping from the back side of the bucking. The other purpose it serves is it makes the bucking more rigid where the nozzle connects, getting a better seal. With a decent bucking that shouldn't be necessary, a good bucking should be rigid enough, but if you have a stock bucking, you'll probably see a noticable difference after taping the bucking.
Gas Mag Parts
The important parts are shown here.
The lip, floating valve, and bb feeder
Oiling Your Magazine
There are really only a few parts to the mag, and the seals are all that need to be oiled. If your mag or gas came with an adapter that has an oil valve on it, follow the instructions that came with it, because your seals will be oiled every time you fill the mag. For "dry" gasses, like propane, you'll need to lube your seals maybe once a month if you use the gun a lot. The more gas you put through the mag, the faster your seals will dry out. For this, I use an silicon/teflon mix areosol spray.
Start with the fill valve, you want a few drops in the valve well, like this:
Then use a propane adaptor (not
attached to a tank) to work the valve open and closed 8-10 times. After that, wipe the excess oil off.
Then oil the floating valve the same way
And work the valve with your finger. Afterwards, wipe off any excess oil.
That's it for regular maintenance. On a less frequent basis you'll want to lube the chamber o-ring, assuming your particular mag has one. You can see how to get to the o-ring in the "fix leaks" section below.
How To Fix Leaks
Leaks in these mags are most likely to occur because your chamber o-ring isn't making a good seal. If the leak is bad enough, you'll actually be able to hear it right after a fill. The mag in the picture had an audible leak when I first got it, so I did the thread mod, which works like this.
Remove the chamber screw
Seperate the halves of the chamber
Remove o-ring and wrap thread around where the o-ring goes. This should cause the o-ring to stand further out, creating a better seal. While you have it open, a little silicone lube or gasket conditioner is a good idea. Hint: the thread will soak up the lube, so go ahead and put some lube on the thread so that it feeds lube to the o-ring instead of stealing it.
How To Improve Gas Efficiency
Improving gas efficiency means getting better use of the gas that is coming out. You won't be getting any more gas out of the mag, but you'll gain a bit of speed/power and your blowback will be noticably harder.
Start by taking the top of the mag off, by removing the pin
With the pin out, you should be able to tilt the top forward, and pull it out of the mag
What you'll see inside is the lip, or the seal from the floating valve to the gun itself.
Pull the lip out, and you'll see the space where it goes underneath. What you're going to do is make a shim to put in here.
To make a shim, I used the plastic that comes from a 6-pack of bottled coke. Anything that is under 1mm thick is good, you don't want it to be high enough to cause it to lose seal at the bottom. You also want to use some kind of plastic so that it doesn't swell or absorb lube or anything.
Using the lip as a template, cut out a peice of plastic that is the same size as the base of the lip
Then cut out the middle to approximately the same size as the base of the lip
Try it in the mag and trim as necessary to get a good fit
When you put it all back together, the lip should stand just a little bit higher off the top of the mag, giving you a better seal with the lip in the blowback unit. If it's not enough, if you still lose more gas than the gun puts to use, add another shim.
After I did this, my 226 kicks like you wouldn't believe, and it hits noticably harder than before. I don't have a chrono to give you real numbers, but the increase in power and kick is definitely noticable, and the whole gun functions better with the mag working more efficiently. You still use gas at the same rate as before, you would need a replacement floating valve to make it use less, but you're putting the gas you use to better use now.