Noob upgrading a TM Hi-capa 5.1
 

Currently trying to build my Hi-capa 5.1 into a IPSC platform... but it's giving me problems to no end.

The stock TM Hi-capa shoots alright - 250-260FPS on .25 g. I also have 2 Marui mags and a WE Mag for it.

Now, what I have done so far:
- TM mags upgraded with a Guarder high performance valve
- Slide to a Shooters Design STI Eagle 5.1
- Guarder Hammer spring and 150% recoil spring
- TK Twist Barrel

Now, this platform will shoot with the WE mag at 250FPS

But when I put in the upgraded TM mags, I have having a myriad of issues. Sometimes the gun would light strike, sometimes it'll fire but with excess gas coming out from the back of the slide/BBU.

How do I tackle the problem from here?

Upgrade your hammer spring to compensate for the highflow valves needing a harder strike

*edit nvm, just read that you upgraded it, try replacing the stock flow valves and see how it goes?

Have you checked your loading nozzle spring and did you check if your loading nozzle is seized by a stiff o-ring?

Yeah, put the stock valve back in the mag and it shoots ok (~250 FPS on .25).

Loading nozzle is okay, otherwise my WE mag should not have given me anything at all. In fact, the whole problem just seems to be the Guarder performance being a prick and is a no-go for my TM HiCapa 5.1?

What exactly can I do to put increase the FPS on my Hi-capa? Nineball Dyna Piston Head?

Tightbore barrel and yeah maybe a better piston head.

Another issue that has been driving me nuts the whole day: My Shooters Design slide keeps getting "locked" back when the slide is pulled all the way back. Putting a 150% recoil spring does not elevate the issue. I've spent the whole afternoon with a file making the action smoother, but I don't seem to have gotten anywhere closer to solving the problem. Thoughts?

Does it bind with the hammer?

What do you mean by hammer binding?

He means is the blowback unit getting caught on the hammer

When it gets stuck, how do you get it back forward? Outer barrels sometimes get caught as well, requiring you to smack the front of the outer to get the slide to return to battery, usually caused by the outer sliding past the hopup chamber

I have to push it from the back, although a slight shake will also send the slide forward.

Could very well be hammer-binding as I can visibly see the hammer moving as I pull the slide back as if it is rubbing against something.

What can I do?

where in the stroke is it getting stuck? 1911s have a habit of getting hung up on the hammer/bbu edge in front of the cocking protrusion.

That's it! Just had a look and that's exactly where it is getting caught.

What's my way out?

You can either file the ramp on the underside of the BBU until the hammer doesn't catch on it or you can file the part of the hammer that makes contact with the ramp of the BBU. Be careful with the filing because you can't bring back the material once its gone.

Yip, filing the underside of the BBU works.

Another question.

I just tested the slide action by firing the Hi-capa on empty. It will only effectively lock back for 15 shots before the mag runs out of gas to push the slide all the way back effective for the slide lock to engage (if my terminology is right).

My control for ambience is a a TM G17 fitted with a PGC metal slide. It will fire on empty for 23 shots before the mag runs out of gas to do the same. A hi-capa mag is longer than a G17 mag. the G17 slide is 220g. The 5.1 slide is 280 g. Temperature is <20*C in New Zealand right now.

Is this normal? 60 g = ~27% heavier than the G17 slide, so 3/4 of 23 = 6 shots less which sounds right.

And if it is normal, what is the next route to making my slide lighter for efficiency's sake?

You can't compare two entirely different platforms for efficiency, it's like comparing a car to a truck to pull a camper.

Mags are all built differently, even though they my physically be the same shape and size or close to, the inner gas well may not be the same size.


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Well, just how do I know whether my Hi-Capa 5.1 is being gas efficient? For a double stacked mag 15 shots is awfully short...

You judge it next to another hi-capa that is the same. Obviously 15 rounds is too little, however the mechanism in the glock and the hi-capa are entirely different giving too many differences to what can cause how much gas is used.

Noob upgrading a TM Hi-capa 5.1
 

Is your loading nozzle cracked? Usually one would upgrade to a harder loading nozzle if there was a metal slide involved. Take your loading nozzle out and squeeze it between your fingers. It should expose any existing cracks. Any crack would allow gas to spew out.

Also check the tm's magazine gas router. Take apart the magazine to get to the router. You may need to replace it or shim it. The mouth of the gas router is supposed to make a seal with the square hole on the bottom of your nozzle to allow the gas to enter it. A bad seal between the router and the nozzle hole will yield weak shots.

Lastly make sure you're not shooting in really cold weather. Propane is tricky...

How exactly (with what?) do I shim the mag seal?

A thick piece of plastic, cut it out to match the shape of the base of the seal.

I would check the integrity of the loading nozzle before the magazine gas router.

yeah, loading nozzle is a-okay when inspected. Even without a physical inspection it's hard to imagine that a cracked nozzle would give you 260FPS on 0.25 gs...

Right, so a few upgrade parts arrived, and I've decided to go back to the drawing board to establish some metrics.

Now, my stock Marui Hi-capa shoots ~ 260-264FPS with stock slide and tk barrel (0.25g BBs for all FPS reports)

Put in the Nine-ball dyna piston kit - 280-284FPS (!)

Put in the Nine ball rubber seal kit - 290-295FPS

Putting both the nineball upgrades into my Shooters Design slide = 265FPS and the gun cannot fire more than 5 rounds(!) before the mag runs out of gas on a full mag.

So the Shooters Design kit I am running is obviously rubbish. My next question becomes: What is a decent metal slide that is basically a "drop in"?

The PGC G17 slide kit worked well when I dropped it into my TM G17. Am I right to think similar good things will happen when I run their kit on the Hi-capa?

Brands that are a good fit to the stock frame:

ILLusion Kinetics
Prog4
Airsoft masterpiece
Airsoft surgeon
Gunsmith Bros