My long in the tooth Tokyo Marui MP5K with SP89 grip. Other than adding a front sling pin and silver dry brush to give it that used look this is bog standard. Even the battery is an old 1,400mAh NiMH that hasn't been removed in eons.
Now it's dead. Expired. Ceased to cycle.
Obviously, the sensible thing to do would have been to check the battery so with that in mind I never bothered my arse and decided that it was something more terminal. In my defence, I had always intended to upgrade this anyway and not working was convenient excuse. As stated in a previous post, I wanted 320(ish) fps and as many rounds per second as I could wring out of it. However, as long as its under 350fps it'll be okay and if I can get 900 rounds per minute that would be great!
I thought I had a Lonex Titan high speed long motor kicking about but it turns out that it is a short version. Bugger. Loathe to spend another fifty quid on a new motor some research on tinternet turned up the SHS motors which seemed pretty decent for around £27 if I was willing to wait until it arrived from Hong Kong or £33 if I wanted to get it from the UK. Grudgingly I forked out the thirty three notes; and the fucker's still not here.
Now it's dead. Expired. Ceased to cycle.
Obviously, the sensible thing to do would have been to check the battery so with that in mind I never bothered my arse and decided that it was something more terminal. In my defence, I had always intended to upgrade this anyway and not working was convenient excuse. As stated in a previous post, I wanted 320(ish) fps and as many rounds per second as I could wring out of it. However, as long as its under 350fps it'll be okay and if I can get 900 rounds per minute that would be great!
I thought I had a Lonex Titan high speed long motor kicking about but it turns out that it is a short version. Bugger. Loathe to spend another fifty quid on a new motor some research on tinternet turned up the SHS motors which seemed pretty decent for around £27 if I was willing to wait until it arrived from Hong Kong or £33 if I wanted to get it from the UK. Grudgingly I forked out the thirty three notes; and the fucker's still not here.
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| Tool Door. Every door needs hex keys and pliers. |
I'd have liked a PDI barrel but they don't make one for the K. They do make one for the PDW though it's a tad longer extending into the flashhider. I found that the PDI 6.01 added about 5% to the muzzle velocity of the TH G18C AEP. That's around a 10-15% increase in efficiency and I would expect a similar result with the short barrel in the MP5K. Spring wise, a Guarder SP100 should do the job though with some spacers to fix the angle of engagement and a bearing spring guide this will likely come in at the wrong side of 350fps - my site limit. I decided to short stroke the gearbox by two teeth which should drop it down by 20fps or so.
The piston is a full metal teeth job which on reflection makes it fairly heavy but I've left the bearing out of the piston head which brings the weigh back down slightly - I'm sure shaving two metal teeth off has had negligible affect though... I did decide to swiss cheese it but gave up - the way I'd drilled it precluded cutting more out so the effect has been minimal and is down to my lack of patience and shit drilling than anything else.
On a side note, the tool door is now looking quite full with almost everything usable or used for airsoft work - although the Knipex mini bolt cutters and wire snips have yet to come into play...
I had originally intend to run the motor on a Firefox 7.4v 1,600mah LiPo but with the way the wiring comes out of the battery it's not possible to fit it without crushing down the wires where they come out of the battery; it would be useful if battery leads came out the end of the battery rather than the side! However, I've ordered aa Turnigy 7.4v 1,300mAh 25C LiPo which looks more than suitable. Overall length is similar to the Firefox at 168mm compared to 170mm but crucially it's slightly thinner at 18x12mm rather than 20x12mm. I did have a look at using a rear wired battery connector which would cut a significant amount of cable out of the circuit but space is at a premium and routing is tight once the end plate is on. The connectors take up a surprising amount of space so I'd probably end up having to use a smaller 1,000mAh LiPo. So, for the moment the front wiring stays.
The bushes on the Marui gear boxes are 6mm - tiny by today's standard - and are plastic to boot. This is actually fine for the standard Marui power but since we're upping that by a fair margin I'll fit some metal bushes to be on the safe side. Obviously, it'll need re-shimmed but that should be a straightforward if time consuming job.
So, to summarise, SP100 spring, short stroked by two teeth, metal bushes, bearing spring guide, SHS High Speed motor and a 7.4v 1,300 25C lipo. Currently in bits on the kitchen table/trolley thing.
The piston is a full metal teeth job which on reflection makes it fairly heavy but I've left the bearing out of the piston head which brings the weigh back down slightly - I'm sure shaving two metal teeth off has had negligible affect though... I did decide to swiss cheese it but gave up - the way I'd drilled it precluded cutting more out so the effect has been minimal and is down to my lack of patience and shit drilling than anything else.
On a side note, the tool door is now looking quite full with almost everything usable or used for airsoft work - although the Knipex mini bolt cutters and wire snips have yet to come into play...
I had originally intend to run the motor on a Firefox 7.4v 1,600mah LiPo but with the way the wiring comes out of the battery it's not possible to fit it without crushing down the wires where they come out of the battery; it would be useful if battery leads came out the end of the battery rather than the side! However, I've ordered aa Turnigy 7.4v 1,300mAh 25C LiPo which looks more than suitable. Overall length is similar to the Firefox at 168mm compared to 170mm but crucially it's slightly thinner at 18x12mm rather than 20x12mm. I did have a look at using a rear wired battery connector which would cut a significant amount of cable out of the circuit but space is at a premium and routing is tight once the end plate is on. The connectors take up a surprising amount of space so I'd probably end up having to use a smaller 1,000mAh LiPo. So, for the moment the front wiring stays.The bushes on the Marui gear boxes are 6mm - tiny by today's standard - and are plastic to boot. This is actually fine for the standard Marui power but since we're upping that by a fair margin I'll fit some metal bushes to be on the safe side. Obviously, it'll need re-shimmed but that should be a straightforward if time consuming job.
So, to summarise, SP100 spring, short stroked by two teeth, metal bushes, bearing spring guide, SHS High Speed motor and a 7.4v 1,300 25C lipo. Currently in bits on the kitchen table/trolley thing.
