text: Tokyo Marui Hi-Capa Upgrade – Part 2 | The Pistol Place
  Tokyo Marui Hi-Capa Upgrade – Part 2
  September 20, 2020 by stevemacg
  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.