Marui Glock 18c hammer/spring problem

[ap27]

My 18c has been acting up lately. Here's what I've figured out so far.

I first noticed that sometimes the gun would do a 'light strike' when i pull the trigger. The bb would weakly fly out of the barrel and the slide would barely move backwards. Kinda like a dud with a GBB. This happened at an outdoor game I attended in June.
While storing the gun and magazines in my basement and plinking there (its relatively cool), the gun 'seemed' to fire normally.
So i ran a test at the Wild Water game today. I kept the magazines out in sunlight for sometime and then tried firing. Got the dud.
Then i filled up the magazine and discharged all gas by pressing the valve. After doing this about 3 times, the gun started cycling properly. However my shots would barely go out to 30-40 feet, even with the hopup turned all the way up.

So, a colder mag (with lower pressure gas, I assume) lets the gun cycle while one that is hot from being in sunlight (higher pressure gas?) causes the dud.
Is this a problem with my hammer or hammer spring? I've tried it with three different magazines so I dont think its my mags or valves. Is something else at play here? I'd appreciate some help so I can get the appropriate replacement parts for it. Haven't been able to game it properly ever since I got it

[cellulose]

It sounds like it very well could be the spring, even if it's stock it doesn't hurt to put in the Shooters Design 150% hammer spring. Though I would also recommend putting in SD steel valve knocker if you're going to change the spring.

I noticed a similar issue in my TM G17, which was wholly due to the stock spring being to weak, all I would get is a quick 'puh' of gas and the slide wouldn't even cycle, upon putting in the new spring it cycled and worked perfectly.

I haven't had any issues with the spring in my TM G18C though I have recently installed a 150% spring in it and used the G18C spring in my G17 which is temporary until I get another hammer spring.

[ap27]

Thanks so much for the reply. I've already got a 150% hammer spring so I'll look into ordering the valve knocker as well.

[RacingManiac]

Hammer spring should fix it. All 3 of my TM Glocks(26, 17 and 18C) was light striking on a warm-ish day or on a really full mag. Hammer spring pretty much cured that. Not surprising considering they are meant for duster gas in Japan...

[MrBond]

Originally Posted by RacingManiac

Hammer spring should fix it. All 3 of my TM Glocks(26, 17 and 18C) was light striking on a warm-ish day or on a really full mag. Hammer spring pretty much cured that. Not surprising considering they are meant for duster gas in Japan...

All Marui Glocks use the exact same spring? (especially the 18c)

[RacingManiac]

They are all interchangeable, but whether they are the same rate or not I don't know. All I know is they all light strike when you get the pressure high enough...

[lanepratt]

Iv notice even with an upgraded spring on hot days it will still do the same, the mag over pressurizes and makes it really hard to tap the valve. Atlest with mine anyway iv bought the 150% up kit for it and still have same results on hot days

[RacingManiac]

I think those small torsion springs are just not that strong in the space allotted vs other GBB's rather long coils....

The G18's long mag does not help neither.

[cellulose]

With my TM G17 I got all the parts from the factory so they were never installed in a frame.

That being said I noticed there were some small areas that were rubbing so I filed them down and now the hammer functions with less resistance. I'm guessing that if you got a Glock that was already assembled you shouldn't have to worry about rubbing though it doesn't hurt to check.

All it took was less than ~.5mm on the valve knocker catch to cause an issue, after filing it functions flawlessly. I also removed a bit for either side of the hammer where the pin goes through and from the hammer chassis where the valve knocker pokes through.

[ap27]

Going to bump this back up. I replaced the hammer spring with an SD 150% one and i still get light strikes on a full mag. Any other ideas as to what might be the problem?

Cellulose, could you please give me some more information on what parts of the hammer/striker assembly should i look at for possible filing?

[solidsnak3]

i've been having the same issue. A fresh mag will pft around 15 times until some of the internal pressure is released. I have the enhanced recoil spring from guarder installed and has been installed for a long time. The gun has been working flawlessly for months but the other night i did some fine sanding on the rails and around the hammer assembly. just to remove some of the paint and create a smoother surface for less friction. Ever since, it seems the hammer isn't moving as smooth, almost like it is rubbing. I took it apart completely thinking that maybe some of the fine metal filings got gonked up with the lubrication and was creating unwanted friction. But once put back together the same thing was happening. Thinking there might be a correlation between the minor filing or "sanding" is creating the issue, i've gone ahead and ordered some new hammer assembly parts in case this is what's causing problems. I find it very hard to believe that this is what's causing the issue though, as i took only enough of the metal off to remove the paint, and not heavily, you can still see there was paint but it's smoother, the amount of metal taken off is in micro-meters, barely detectable. I truly think that there is something happening with the hammer and the firing pin's relationship. Maybe it's just the hammer spring, i should try putting the stock spring back in, i hear the new glocks are stocked with stronger springs capable of withstanding green gas.

I am really curious if ap27 got his issue all figured out. It seems cellulose had the right idea, but has yet to respond with any insight regarding his focus on the parts he filed.

also i should mention that when cocking the gun, all the internals move and function properly. hammer is locked, sear is tripped trigger is rest. It's only when gas is introduced that there is mechanical issue. fuck!

[mmmken]

If your gun has been working before and suddenly has developed symptoms as described, I really doubt your hammer assembly is the cause. Paint and tolerances don't just get thicker over time, and I'm sure you tried cleaning the assembly before posting.

Try taking apart your BBU assembly and checking your nozzle. Check for any cracks in the plastic and see if it glides back and forth on the piston head rubber without much resistance. If possible: try replacing both the piston head, rubber, and loading nozzle altogether - ensuring they are all the same brand for best results. Like the hopup rubber, the rubber on the piston head can swell over time with oil and cause excessive friction. If your nozzle is cracked, then it does not deliver enough gas to rack the slide backwards. Both these problems do display the symptom of "light strikes and little recoil action" as well as jams if your piston head rubber has been swelled up.

The above seems even more likely since you mentioned your mag is good for only 15 light shots - which probably indicates both "inefficiency" and "that its not actually light striking".

If the gun has never worked before and you have a heavier metal slide, try using either hi-flow valves or a WE magazine (that comes stock with hi-flow) as a temporary fix.

[shootersaber]

You need a stronger hammer spring. Under sunlight , the magazine is hot, gas pressure go up. So your g18c hammer can not open the valve enough. you can change the guarder recoil & Hammer Spring.
http://www.tokyo-model.com.hk/shop/g...?cPath=1_39_63