Tokyo Marui Hi-Capa Upgrade – Part 2

The next step in the upgrade of my Tokyo Marui Hi-Capa is to fit the upgraded loading nozzle. The loading nozzle is the part that pushes the BB into the barrel when the slide returns to battery and the front part of the loading nozzle fits tightly inside the barrel. The better the seal between the front of the loading nozzle and barrel, the less gas you will lose here and the higher and more consistent the fps should be.

To fit a new loading nozzle, you must first remove the blowback unit which is located in the rear part of the slide. On the TM Hi-Cappa, it’s held in place by a 2.5mm hex screw at the rear of the slide. To remove the unit, first remove this screw…

Then, remove the blowback unit by sliding it down and out of the slide. When it’s out, you’ll see that there is a long trough in the top of the unit, inside which fits the loading nozzle return spring and the retaining tab for the loading nozzle (arrowed below).

To remove the old loading nozzle, just slide it forward and angle it so that the retaining tab clears the slot. Then, fit the new one in the same way. Put the return spring back in the slot and re-fit the blowback unit in the slide. It’s best to do this with the slide right-way-up – if you try to do it with the slide upside down, the nozzle return spring may fall out and prevent the unit from seating properly. Once you’re happy that it’s properly seating in the slide, re-fit the hex screw and you’re done.

Finally, it’s time for the new hop-up rubber and tightbore barrel. Take the inner and outer barrel out of the slide and take the inner barrel and hop-up unit out of the outer barrel by sliding it to the rear. Split the hop-up casing by removing the two small cross-head screws (arrowed below).

Take out the metal hop-up adjustment arm then lift out the existing barrel and hop-up rubber. You’ll see that the hop-up rubber has a large, rectangular tab on it which fits into a slot on the right-hand hop-up casing. Fit the new hop-up rubber to the new barrel. The open part of the barrel must face towards the top of the pistol while the rectangular tab on the hop-up rubber faces to the right. Basically, just make sure that you replicate what you find with the existing set-up.

New barrel and hop-up rubber (top) and original barrel and hop-up (bottom).

Press the tab on the hop-up rubber into the slot on the right-hand hop-up casing, then re-fit the hop-up adjustment arm, making sure that the small tab on the end of the arm fits inside the slot in the adjustment wheel (arrowed below).

Now re-fit the left half of the hop-up casing and you’re done. Reassemble everything and you’re good to go. Now, that wasn’t so difficult, was it?

Now for the good bit – time to try shooting the upgraded Hi-Capa. I’m using Green Gas for these tests – with the upgraded recoil spring, this replica now won’t function with HFC-134a. I want to use the upgraded recoil spring because this returns the slide to battery faster, providing snappier blowback and a harder kick. However, be aware that this can also cause accelerated wear on plastic slides. But just like all these upgrades – you can always change it back if you’re not happy with it.

The first thing I did was to run ten shots over my chronograph using 0.2g BBs. Even before I noticed the numbers, I was aware that this replica is now louder and the kick is much stronger than it was. It’s now right up there with the hardest kicking blowback replicas I have tried. The numbers were pretty good too. If you have read the review for my standard Hi-Cappa, you may recall that it chronoed at an average of just under 230fps. It was a few degrees cooler than when I first ran it with upgrades over the chrony, but this time the average for a ten-shot string was 304fps, with a high of 307 and a low of 295. That’s a pretty impressive improvement of over 30% in the speed at which BBs are leaving the barrel. It seems to work as it should too, with BBs feeding and shooting reliably. Time to try some target practice.

Initially, results were a little disappointing, but I think that’s almost certainly due to the new hop-up rubber taking time to break-in. By the time I had shot around 100 BBs, groups were getting noticeably smaller and I was able to use 0.25g BBs and to get them to shoot to the point of aim. Overall, I’d say that accuracy and consistency have improved marginally over the original, but then it was pretty good in the first place and it’s possible that the hop-up will improve further and that accuracy and consistency will continue to improve. BBs certainly hit the target with more power now, the kick is much stronger and I’m able to use 0.25g BBs, which is what I had hoped for.

10 shots, 6m, 0.25g BBs. The point of aim was the top of the black inner circle. The black circle is 30mm diameter.

Are there any drawbacks? Well, using this setup and Green Gas, I’m getting around 35 shots before I run out of gas compared to 70+ shots in standard form and using HFC-134a. So, I’m certainly using more gas, but I’m not unhappy about trading off a reduction in gas efficiency against improved kick and more power. There are people who say that using Green Gas in TM replicas will damage the slide, but I haven’t seen any signs of damage yet and I know people who have used Green Gas in TM replicas for years without problems. I took advice from Mike Cripps at Elite Shooting Centre who reassured me that the TM Hi-Capa with these upgrades is safe to use with Green Gas.

Part of the issue, I suspect, is temperature. Gas powered replicas are very dependent on temperature – the hotter it gets, the higher the pressure of the gas. I think that in warmer weather (say, anything over 25°C), I’d be tempted to revert to HFC-134a and the original recoil spring on this replica, just in case.

Overall, I’m very happy with these upgrades. They aren’t expensive, they’re fairly simple to fit and they do make a noticeable difference to shooting my TM Hi-Capa. I’d recommend these upgrades and the expert advice from Elite Shooting Centre to anyone thinking of upgrading their TM Hi-Capa or any other Tokyo Marui replica.

Happy shooting

Related pages

Tokyo Marui Hi-Capa Upgrade Part 1

Tokyo Marui Hi-Capa Custom Dual Stainless review


Elite Shooting Centre

Tokyo Marui Hi-Capa Upgrade – Part 1

If you have read my review of the TM Hi-Capa 4.3 Custom, you’ll know that I was very happy with it. It’s beautifully made and it shoots very nicely indeed. However, I did wonder whether it might be possible to upgrade it for a couple of reasons: one, I’d like it to shoot with a little more power, which would allow me to use heavier BBs, and, two, I’d like to be able to use Green Gas rather than HFC-134a. This would help with the first point and would also mean that I’d need to have only one type of gas for my replicas.

I was fortunate during my research for the review on the TM Hi-Capa to come across Elite Shooting Centre in Bury in England. This small company is run by Mike Cripps, a man who knows a great deal about competition shooting and TM Hi-Capas. Mike was a member of the UK Squad at the World Shoot X in Bisley in 1993 and he won the very last UKPSA Competition using firearms to be held in the UK. When firearm law in the UK changed in 1997, Mike switched to shooting with airsoft pistols and in particular with TM Hi-Capas. He won the UK Open Championship in 2003, 2004, 2006, 2008 and 2009.

In 2004 Mike started Elite Shooting Centre (you’ll find a link to his website at the end of this article). Initially, this included a retail store as well as shooting ranges. However, in time the focus of the business changed to supplying parts for and building custom airsoft pistols for IPSC and pistol shooting. Mike only builds and provides parts for TM Hi-Capa pistols. Obviously, Mike is very knowledgeable about these pistols, and so I asked him for guidance when I was thinking about upgrading.

His advice was fairly straightforward – keep it simple and upgrade only using parts which are a straight replacement for stock. His recommendation was that I fit a tightbore barrel and upgraded hop-up rubber, an uprated loading nozzle and 120% hammer and recoil springs. Mike was kind enough to provide the parts needed to upgrade my replica, so, let’s see just how easy it is to upgrade the TM Hi-Capa…

The parts

Mike kindly provided several replacement parts for my TM Hi-Capa. These are:

    Elite tightbore 6.02mm barrel

    UAC replacement hop-up rubber

    Gunsmith Bros. uprated loading nozzle

    AIP Enhanced 120% hammer and recoil springs

Fitting all of these should simply be a case of swapping the uprated parts for the standard parts. None of it sounds too challenging, so let’s see how it goes.

First, the replacement springs. The parts Mike provided come from Hong-Kong based AIP (Army International Products). The upgraded recoil spring should provide improved recoil effect from the blowback, though you should only fit an upgraded recoil spring if you are planning to use Green Gas – HFC-134a just doesn’t provide enough power to deal with an upgraded recoil spring.  The hammer spring will lead to a harder hammer strike, which will cause more gas to be released with each shot, hopefully providing improved fps. The downside is that this will also use more gas, but as the TM Hi-Capa is pretty frugal with gas, I’m prepared to accept that trade-off.

Replacement AIP 120% recoil spring (top) and TM original (bottom)

Fitting the upgraded recoil spring was no problem – I just removed the guide rod, bush and spring from the slide, replaced the old spring with the spiffy new one and put everything back together.

Replacing rhe hammer spring was little more tricky. The mainspring housing on any 1911 style pistol is in the base of the rear of the grip and it’s essentially a self-contained module which has to be removed to access the hammer spring. One useful tip is that it’s best to lock the grip safety in the engaged position before you remove the mainspring housing. The grip safety uses a leaf spring with fingers which can be bent or damaged when you re-fit the mainspring housing, but if you use tape or an elastic band to hold the grip safety in before you remove the mainspring housing, this won’t be a problem.

Pin which retains the mainspring housing (arrowed). Masking tape is used to hold the grip safety down.

To remove the mainspring housing, all you have to do is drift out the pin in the bottom rear of the grip. The pin has a pronounced dimple on one side and that’s the side on which you should place your drift.

Pin partway out.

With the pin removed, tension on the hammer spring will cause the housing to move around 1/8” down. Just slide it out the rest of the way down and out of the grip.

If you then look into the top of the housing, you’ll see the dished top of the hammer spring pin and, coming from the left side of the housing, a small plastic pin which stops the hammer spring and pin from twanging out. All you need to do is push the small plastic pin to one side and the hammer pin and spring will come out.

OK, I know it’s a little difficult to see in this picture, but if you look into the top of the mainspring housing, you’ll see the dished top of the hammer spring pin and the small plastic pin which pushes in from the side and holds this in place (arrowed)

This is one part of the job where you’ll need to be careful if you don’t want small parts springing off into the middle distance. When you push the small pin to the side, tension on the hammer spring will cause the spring pin and spring to twang out of the housing. Guess how I know that? And, if you’re working close to an open first-floor window where the light is good, you may be especially unlucky and the spring pin will bounce out of the window, on to the balcony and then down into the street below. And you’ll then spend fifteen minutes looking like a complete dork as you wander up and down, scouring the street outside looking for the missing pin. Guess how I know that too? And against the odds, yes I did find it. It’s lucky I live on a very quiet street! To avoid similar problems, all you have to do is make sure that your thumb or something else is over part of the opening at the top of the mainspring housing before you slide the small plastic pin to the side – this will stop the hammer spring and pin popping out.

New AIP 120% hammer spring (left) and original TM hammer spring (right)

Anyway, once the old spring is out, you just replace it with the new one and reassemble everything. Just out of interest, I put everything back together at this point and tried the slide and hammer. And yes, the hammer feels harder to cock and the slide is harder to rack. Nothing dramatic, but you can certainly feel the difference. Which is encouraging…

In Part 2, I’ll fit the tightbore barrel and hop-up rubber and replace the loading nozzle. And I’ll finally get round to doing some chrony testing and shooting with my upgraded TM Hi-Capa to see if these changes provide a notable improvement.

Related pages

Tokyo Marui Hi-Capa Upgrade Part 2

Tokyo Marui Hi-Capa Custom Dual Stainless review


Elite Shooting Centre