Black Knight's HPA odyssey

[Black Knight]

Hmm... The more I think about it, the more feasible it sounds to make an additional wire, which would run from the back of the gearbox to the handguard along the groove in the gun body. I do know my way around a solder iron, so it would just be a matter of sourcing a suitable wire and a couple of connectors. And of course making sure that the leads in the additional wire match those in the original wire harness, but that should be simple enough, as the are color coded. If I can't live with the solid stock, I'm sure as hell gonna give it a try.

 

I did test the MP5 last sunday, but I was unable to skirmish with it. This is not the result of the HPA engine, though. The gun is second hand and the original owner has busted the front end piece, to which the front sight is connected. It's smartly replaced with a 3D-printed piece, but it lets the banana wobble slightly. Not much, but just enough so that bb's are hitting the banana end piece when firing. Should not be a problem, as I'm just going to drill the front end hole a little bigger. And maybe put in a slightly longer barrel. The current one is the Cyma stock 229mm one. The only thing I'm worried about is the gun's sound signature. I want it to be just as quiet as my AR was. The banana is a little bit shorter than the one I used in the AR, so I'm going to have to do some experiments with different fillers for the can.

 

I also changed hopup buckings yesterday. The MP5 had the Prommy purple bucking, which performed well in my AR, but the Cyma stock hopup unit does not press the bucking lips much and the bb almost falls directly through, if the hopup is set to zero. I put in a Madbull red bucking which should retain the bb a little better during the loading cycle.

 

Other things worth mentioning are that the 229mm stock Cyma barrel required about 100 psi pressure to get to 1.6 joule muzzle energy with a 0.25g bb. And the Cyma MP5 midcaps have pretty stiff springs in them. I cranked the ROF up to about two thirds from maximum and the mags were able to keep up pretty nicely. My chrono does not measure ROF, but one fast trigger pull produces about 5-7 shots, which is already quite intimidating and more than enough for me. Good thing that the gun came with 10 magazines..

[Black Knight]

I tested both the MP7 and the MP5 yesterday.

 

When I last fielded the MP7, I had issues with the grease in the engine becoming too thick in cold weather and the gun would not cycle properly on the first shot. This time we had about +16°C and the gun cycled flawlessly. I did not play with it, but I let it sit pressurized for about three hours before testing. Might experiment changing the lubrication from TechT to just normal silicone oil at some point. Just to see if it makes this little puppy work in cold weather also.

 

I also tested the MP5 with the Madbull red bucking. I have secured the silencer from wobbling with o-rings and drilled the end hole to 16mm from the original about 11-12mm, but still the gun fires very erratically. Bb's are pretty much all over the place at about 20 meter range and curving like crazy. Side-to-side alignment should be okay and at a quick clance there were no marks of bb impacts in the silencer end cap. Gonna have to investigate further.

 

On a side note, a friend of mine managed to put the Bingo MP7 engine into a Scorpion AEP. Can't remember the manufacturer, but it's a TM AEP clone.. The selector is non-functional but other than that it works just fine.

[DarkLite]

Madbull buckings are total garbage.

[Black Knight]

Hmm... I would not say that all of them are garbage. Sure, the hopup mound inside the bucking itself is rather large, so you have to use a very small nub on the adjustment side of the hopup mechanism. Also, the bucking diameter is large, so getting it to fit into some hopup chambers might require rather large amounts of lubrication. But I do have MB blue buckings in most of my AEG's and I'm getting 2-3 fps variance in velocities between shots. I like the fact that the bucking lips are noticeaply thicker than in for example Prommy purple buckings. And my common sence tells me that when the lips press more firmly against the nozzle, you get a better air seal.

 

The only thing I have gotten better groupings thus far is the Maple Leaf Monster(TM M14 hopup chamber+Maple Leaf+PDI 6.01 tightbore = WIN), but that unfortunately does not work well with my ProWin M4 hopup chambers, which I have in all of my AR's. The chamber applies so much pressure to the bucking lips, that the tappet plate spring can't push a bb through the lips. And the bucking lips are so long that they hinder bb feeding. I think that a pretty much perfect bucking would be a Maple Leaf made out of the same material as the blue MB ones and with the same "short and thick"-style bucking lips..

 

It should also be noted, that my positive experiences only apply to the blue buckings. I have seen mixed results from the red ones. I used one in the MP5 as the Prommy purple one gave me quite a lot of vertical inconsistency in qroupings and MB red bucking is actually what Wolverine recommends. Just have to do some experimenting, I quess..

[malcolmg]

I have plenty of guns that shoot well with Madbull buckings *shrug*

 

Buckings are very picky about the hop chambers you put them in, which is one of the reasons why you can get such diametetrically opposed views as to their efficacy. I never close my mind off to trying ones that I have previously found to be unworkable in other guns.

 

I treat hop chambers in much the same way, magazines too.

 

/edit: Muh words!

[Black Knight]

So very true, sir..

[Black Knight]

Tested the MP5 with a Maple Leaf 70° bucking yesterday and it shoots much better now. Not sure if it's called Monster or Delta or whatever..   It's the newer one cyan colored one.

 

At first I was a little sceptical whether the Maple bucking would work, as the Cyma hopup chamber puts zero pressure on the bucking lips and the bb would just fall straight through the chamber and barrel, when the hop was set to zero. But once you give it a little hop, you need a reasonable amount of force the get the bb through.

[Isamu]

I'm sorry if this looks a bit off topic, but, regarding the bucking, which nub are you using? a regular nub? maple leaf nub? other?

 

Thanks for the info, I had one of those in my boneyard ICS M4 and with a Poseidon barrel it was totally terrible, probably due to something in the gun (never shot properly). Now i'm waiting for a game to test it in a "reliable" gun, but I wanted to gather as much info as possible =)

[Black Knight]

No problemo, I have written quite a bit of off-topic myself..

 

I'm using the Maple Leaf nub in the MP5.

[Isamu]

Great, I should have a spare one in the "hop up bin box"

 

Thanks, man =)

[Black Knight]

Been a while since the previous update. I have been busy putting Titans in all af my AR's and I have not skirmished with any HPA stuff, as I'm putting the newly-built AR's through their paces.

 

Anyway, during the summer, I finally managed to get the MP5 to shoot well with a Prommy-barrel and the Maple Leaf-bucking. And I also solved all the silencer wobble issues. And then the Inferno engine developed a malfunction where the gun would fire one bb and then start leaking air through the nozzle. I managed to rectify this with a thorough cleaning and re-lubing of the engine...

 

...but I still ended up selling the gun, as the leaking-malfunction completely killed my trust in it. I do have to say that this decision was also a little bit biased by the fact that LCT came up with a steel G3. And somehow I like to hope that they will come around to making a steel MP5 also. So I'm juuust a tiny bit looking forward for that one already...  We shall see if my hope in LCT is misplaced or not.

 

To summarize my experiences with the Inferno engine, I would say, that I had very good initial experience with it, then ran into a couple of problems that ultimately killed my trust in the engine. At the end of the day my Inferno was on my table more than on the field. Somebody else's experience might differ, but that's the truth for me. But at the same time, I gotta say that I am tempted to try out a closed bolt engine. The low sound signature is just sooo sweet of a thing to have in a gun...