Tokyo Marui Hi-Capa 5.1 and Prog4 hammer set upgrade problem

[hawai]

Hi,

I am new here and also to the world of Airsoft IPSC pistols. I just came across of this nice forum with lot of usefull info, thanks for that !

I have a question about a hammer set upgrade / modification for my Tokyo Marui Hi-Capa 5.1. I have the following ''Prog4'' hammer set :



With this hammer set from Prog4, i have replaced the orginal Sear, Knocker, Hammer Spring Plunger and of course the Hammer and Strut from my Tokyo Marui Hi-Capa 5.1.

If i put the lower receiver and grip together again and try to fully cock the hammer and pull the trigger, the hammer stops half way and the Knocker won't get slammed by the hammer.

If i ONLY put the orginal TM hammer en strut back and test the same, the hammer will fully decock when pulling the trigger and everything seems to be working fine. I have looked to see any differences between the TM and Prog4 hammers, but i just can't find any clue for this problem.

Can somebody help me ? Thanks a lot !

[apilar]

My guess would be to adjust the 3 finger leaf spring. However this is a finicky process.. a very common solution to this problem is to entirely remove the half cock notch. This will ensure that you never have the hammer stop in half cock position!

[hawai]

Originally Posted by apilar

My guess would be to adjust the 3 finger leaf spring. However this is a finicky process.. a very common solution to this problem is to entirely remove the half cock notch. This will ensure that you never have the hammer stop in half cock position!

Hi Apilar, thanks for the tip, i didn't know that it was possible ! Why is there's a half cock notch on the Hi Capa hammers ?

I can dremel the half cock notch away like this ?



This is the Prog4 and TM hammer :

[apilar]

To my knowledge the half cock notch is a type of safety. The 1911/hi capa has the slide thumb safety and the beaver tail safety but the gun can also be put into half cock position as an additional safety feature.

Presumably you could carry your gun with on in the chamber and in half cock position and it would be equally as safe as having the thumb safety engaged while the hammer is fully cocked.

For the airsoft world it has no real function. My only guess would be you could possibly de-cock the hammer to half cock.. but I would be terrified of losing my thumb on the slide because the hammer will hit the valve in the magazine regardless of how slowly u release the hammer.(as far as I know)

The highlighted area is the half cock notch that you can remove if you wish. You can also attempt to bend the 3 finger leaf spring. When installed in the gun, the farthest left finger should be bent toward your face- quite a bit too. So much so that the 'ring' on the arm is above the frame.

The middle finger should be just about completely flat, with maybe a slight bend away from you.

The right finger should be bent a bit farther away from you then the middle finger.

This is difficult to explain and is much easier to do in a trial and error fashion. If you feel like putting in the time you can try to bend and arrange the leaf spring yourself just to save you from permanently modifying any parts if you are leary of that!

I have installed after market hammer sets myself. I will let you in on a few things to look for that can potentially give you headaches down the line.

From the photo, a disconnector and knocker valve lock were not included. These two parts are the ones that sit on either side of the frame- disconnector on right side (sort of V looking piece) and on left Is the knocker valve locker(with the spring that pings off into oblivion if you are not careful)

That being said, aftermarket parts are almost always over sized. This will make fitment potentially troublesome. With regards to the knocker valve lock it may come with a new stiffer spring to handle the new steel part. This upgraded spring has caused me problems and I found the stock one to be better.

With regards to the disconnector you may find u pull the slide back all the way. It gets stuck. Will not go forward and will not move backward anymore. WHY!? Because if you look into the chamber where the disconnector is you will notice the blowback housing(bbh) has arms, and these arms are what push the disconnector and knocker valve locker down. When the slide Is pulled all the way back the arms on the bbh are not long enough and the disconnector comes up infront of the arm essentially completely blocking all movement. Do not panic, push down the disconnector with a screw driver or something to get the slide to come forward again. Remove the slide because this will happen always.

Take out the disconnector and slightly round off the side that interacts with the bbh arm. On the bbh round the arm that interacts with the disconnector - basically make each piece into a ramp so they can smoothly glide over top one another.

Finally, if you find that after all this ur ready to go, rack the slide, pull the trigger and it fully de-cocks and u chuckle and think damn I'm good.. well.

Now you put the magazine in with ur hammer cocked and she shoots! Excellent. So you take it to do some plinking, this time the hammer is NOT cocked when you put the magazine in. You rack the slide to chamber the bb and.. nothing.

Ie- gun only shoots when the hammer is cocked with the magazine out.

This is caused when the firing pin gets stuck on the magazine valve. Again a problem with oversized aftermarket parts. You would notice that the valve on the magazine has a ramped edge around the striking surface. This edge is so when you put the mag in, the firing pin can glide past and slip behind. With the aftermarket firing pin it is a bit longer and more square and it catches on the valve edge and will not retract to slip behind the valve so when you pull the trigger, the firing pin and valve are not lined up.

The solution would be to round the bottom edge of the firing pin to match the angle on the valve better. At the same time, take off the smallest bit of length. Always do this in baby steps and test fit as you go when modifying any parts.

Anyways! Best of luck. I would be hesitant to do any of heavy modification yourself. I am only giving my personal advise and in no way would I enjoy seeing you mess up a gun trying to replicate everything I've said. In all honesty I think you can get the 3 finger spring working with the half cock notch if you give it the time to test and test. The other info is just tips I've picked up. Look for them if you run into problems down the road! If you are ever really unsure a pistol smith can always install your parts for you!

[hawai]

Hi Apilar, thanks for all the information. I have an old spare 3 finger leaf spring which i will use for the testing. This one comes from an old KJW KP05 Hi capa and the farthest left finger is already bent a lot forward comparing to the TM 3 finger leaf spring. I am curious how this will work

[mighty_kit]

in my experience, the problem is the half cock nub. when you inserted it in the hammer, you used too much force.
as apilar said, you can easily take off the nub.

[Sequential]

The half cock'ed nub don't use it with the hammer.

[hawai]

Thanks guys for the tips, i tried the sear spring but did not succeed. After filling of the half cock nub step by step, the problem is solved. My race gun is now finished and shooting fine !

[jordan7831]

a lot of useful info here thanks apilar.

[hawai]

It's have been a long time ago that i had this probleem, but i have to add...don't cut the half cock nub. After a period it gave me more problems with finetuning the leafspring even after installing this hammer in another setup. Full auto problems, auto fire while changing mags....bought a new hammer set, installed it, fine-tuning the leafspring after getting more experience and info from the web. No problems anymore and i feel confident about it