FPS upgrades for HK53 (TM MC51 upper, CA ca33 lower)

[PeteJC21]

Hi,
I have an HK53 which is basically the upper from a TM MC51 and the lower from a Classic Army CA33... its firing at about 270fps with .2g bbs and a 8.4 1100mah battery. I want to get it to around the 320-330 mark. Any suggestions?

I'm still fairly new to airsoft so have never tinkered before.

[Montesa77]

Re: FPS upgrades for HK53 (TM MC51 upper, CA ca33 lower)

Systema M100
Metal bearings
Bearing spring guide
Then all the AoE mods and shimming ect.

I guess none of those make sense to you. You could always send it to some one like *cough* Z1 *cough* for a £35 per hr excluding parts or *cough* send it to some one on here.

[PeteJC21]

Re: FPS upgrades for HK53 (TM MC51 upper, CA ca33 lower)

£35 quid an hour? No thanks will research and do the work myself!

M100 = new spring? Would this be compatible with my gun and what sort of fps increase can I expect from each of those parts?

What would a 9.6v battery do? Just increase the rof and the trigger response time?

[North West Outpost]

Re: FPS upgrades for HK53 (TM MC51 upper, CA ca33 lower)

Pretty much yes, if you could do worse than add one of the Dream Army mosfets into the list, then it would be really nice to use. I wouldn't bother changing the motor if you have one of the blue high torque CA ones.

M100 yes new spring, depending on Manufacturer should loosly depending on many things...Give arround 330 fps.

If I was you as you seem to be asking some very basic questions, I would either get someone to do the work for you or spend some time doing plenty of research befor trying things yourself.

[PeteJC21]

Re: FPS upgrades for HK53 (TM MC51 upper, CA ca33 lower)

To be honest I probably know more than I'm letting on, I just like to keep the questions very basic to start with to avoid any confusion. I've stripped and rebuilt gbb pistols before but haven't really touched aegs yet.

Also, with thus gun, I get the occasional problem where it dies on me. It'll be working fine one minute then next I pull the trigger and nothing happens. If I keep trying or switch backa dn forth between safe/semi/auto then eventually it'll start working again. Any ideas? I've tried a different battery and although its not doing it as much it does still do it, so I don't think its the battery.. Loose connection somewhere inside maybe?

[North West Outpost]

Re: FPS upgrades for HK53 (TM MC51 upper, CA ca33 lower)

Without having the gun infront of me, it could be loads of things. I would try loose connections, nipped wire or trigger contacts to start with.

[PeteJC21]

Re: FPS upgrades for HK53 (TM MC51 upper, CA ca33 lower)

Without having the gun infront of me, it could be loads of things. I would try loose connections, nipped wire or trigger contacts to start with.

Ok thanks, I'll pull it apart and have a look, if I cant figure it out I'll send it to someone who can.

[Clot]

Re: FPS upgrades for HK53 (TM MC51 upper, CA ca33 lower)

The stock CA lower on that gun has 6mm metal bushings as standard, it will run an m100 fine.

If I remember rightly - mine came with a full cylinder. Stick a vented one in there and your fps should go up.

[North West Outpost]

Re: FPS upgrades for HK53 (TM MC51 upper, CA ca33 lower)

Thinking about it, it's unlikely to be trigger contacts if you wiggle the selector to get it to work...Id go with loose connection arround the selector plate area...Holds breath...

[PeteJC21]

Re: FPS upgrades for HK53 (TM MC51 upper, CA ca33 lower)

Thinking about it, it's unlikely to be trigger contacts if you wiggle the selector to get it to work...Id go with loose connection arround the selector plate area...Holds breath...

Well I'm not 100% sure that fiddling with the change lever actually helps get it working again, but this is what I seem to automatically do... sometimes it starts again, sometimes it doesn't.

Today it refused to work again for quite a while. I swapped a few batteries over, gave it a shake, swore at it... nothing. I came back to it a bit later and it worked again for a few shots then died again.

A girl there was having a similar problem with her M4 (don't know the make).

[PeteJC21]

Re: FPS upgrades for HK53 (TM MC51 upper, CA ca33 lower)

Okay quick update and advice time.. I've starting stripping it all down and managed to get the gearbox and motor parts out. It seems I do have one of the CA high torque motors that midas mentioned above.

Below is a few pics of the parts. I assume its a fairly standard looking gearbox, before I continue to take this apart is there anything I need to worry about?

My main concern is once I take the screws out and take it apart springs and gears are going to drop out and fly everywhere! I read TB-Stalkers tech guide on this forum so I'm prepared for the spring to pop out and will try and stop that. Anything else?

[TB-Stalker]

Re: FPS upgrades for HK53 (TM MC51 upper, CA ca33 lower)

When taking it apart for the first time you may need to prise the gearbox open (using a precision flat head screwdriver) just to get it started as they can sometimes be a bit sticky, and remember to push the spring guide in before you take it apart. I also find that holding down the cylinder can stop the spring from bowing and flying out.

[TB-Stalker]

Re: FPS upgrades for HK53 (TM MC51 upper, CA ca33 lower)

The stock CA lower on that gun has 6mm metal bushings as standard, it will run an m100 fine.

If I remember rightly - mine came with a full cylinder. Stick a vented one in there and your fps should go up.

I think you have that the wrong way round, vented cylinder will lower the fps and you should use the correct cylinder type for your barrel length to prevent suck back, not to alter fps.

[PeteJC21]

Re: FPS upgrades for HK53 (TM MC51 upper, CA ca33 lower)

Ok, got it open. Now the big spring I pulled out thats the spring upgrading to this Systrema M100?

Attached are a couple of close up photos... can anyone see anything obvious that could be causing the random stoppages? I've checked all the wiring, looks all intact to me. Where are the connections for the selector plate area that midas mentioned?

[TB-Stalker]

Re: FPS upgrades for HK53 (TM MC51 upper, CA ca33 lower)

Aha! Problem seen! Yes the big spring is the one you will be swapping out for the M100. The problem is that your Bevel gear (the top one that engages with the piston) is timed wrongly which is what is making it lock up.

It should look like this:



The circle that is raised on the bevel gear that engages with the piston should be at the 1 o'clock position. Yours needs to be turned 180 degrees clockwise. (Looking at the first picture)

Hope that helps.