Fixer-upper Part 4: Classic Army P90

Here we are again. A broken gun up for grabs for cheap on a For Sale site. And grabbed it I did.

Patient: Classic Army Sportline P90
Symptoms: "Has had some electrical issues, been to a tech but stopped working again quite some time ago and has been unused since"

I've never owned a P90 before, but it has been on my get-one-some-day list for some time. This one is from the Classic Army Sportline series, meaning the externals are mostly plastic. Now, the real P90 is mostly plastic as well, so it did not bother me that much, even though usually I'm a stickler for realism in materials. Compared to a real P90 the only thing not of similar materials is the upper receiver. The outer barrel and flash hider are metal, as are the optics rails. Furthermore, metal uppers should fit right in if I ever want to get one.

The gun came with a Swiss Arms C-more style red dot (with a missing front clamp), two hicap mags, two NiMh batteries and a dumb charger. The internals had been upgraded to some degree, but the previous owner did not know much about them. In his words, he didn't know what had been done, the gun had been to a tech twice for electrical problems and now just would not fire at all.

Troubleshooting

It didn't take long to find out that the batteries had simply died. With a fresh 7.4 V LiPo this thing came alive, if only on full auto. Something was wrong with the semi function, and I could hear a rattling sound coming from the inside when the gun was tilted back and forth.

Externally everything seemed good apart from a small crack in the rear of the receiver. The two sides of the front grip also did not quite stay put due to a screw having lost it's threads. Nothing to hinder functionality, that is.

The P90 turned out to be exceptionally easy to disassemble. As you might know, my first gun was an AUG. That was very easy to gut, but this one was even better.

After popping the back plate, you see two screws. Take those out, remove the plate they held down, and the gearbox comes out.

The P90 uses a less common V6 gearbox, so replacements and spare parts are somewhat harder to come by than on your average AK or M4.

The upper receiver can also be removed simply by pressing a rectangular button on top of the receiver and sliding the whole assembly out. I could not help but fall in love with the design straight away.

The modularity was not limited to the externals. The gearbox comes easily apart as well, separating the motor cage, wiring and trigger switches into an assembly away from the main body. No wires to stop you from working, and you can test everything without inserting the GB into the gun.

The problem with the semi auto not working quickly became apparent once I peeked into the trigger switch assembly. A part had broken off from the trigger trolley (seen above still wedged below the trigger contacts). With the piece off, the trolley would simply skip over the trigger switch, not move at all and thus not engage the contacts.

The rattling I heard when tilting the gun was not an extremely short spring as I though at first (the gun chronoed just above 0.6 J), but rather the broken stem of the plastic spring guide sliding inside the spring.

The two main problems had been identified, and I got to work fixing them.

Fixing-upping

In addition to fixing what was broken, my plan also included swapping the plastic bushing for steel ones and re-shimming, fixing AOE, installing a MOSFET, and putting in a flat blade fuse and deans connectors. My plan was to build a CQB beast with a high ROF and moderate power.

Swapping out the broken spring guide seemed rather straightforward, as I quickly found a steel spring guide in my spares drawer. The V6 box takes V2 spring guides, which makes it easy to replace. Or so I thought.

A couple of test shots later the spring was compressed into the piston, which in turn was stuck in the rearward position. In case you've never done it, let me tell you that disassembling the gearbox again with this kind of a mine inside is just lovely. I managed to get it out without issue, luckily, only to have it get stuck again (because of course I had to try it again). It was pretty clear that the spring guide would not work here.

I scavenged another spring guide from an M4 parts box I had lying around, waiting to get assembled. It was otherwise similar, but the end was tapered and, more importantly, it had a diameter that was 0.21 millimetres smaller. The one fifth of a millimetre was all that was needed, the spring did not get stuck. The spring, as well as I, was free to move forward.

Swapping out the plastic bushings for steel ones was pretty straightforward, but they did sit quite low in the shell, and I had to use more shims than I've ever had to before. At some point I began to question whether or not I was doing something horrendously wrong, as the the combined thickness of the pile of shims on the spur gear crossed the 1 mm mark. It worked swimmingly, though, so that's tolerances for you.

Trying to fix the angle of engagement on the piston turned out to come with its own set of problems. The piston head was attached with a tiny nut sitting free inside the piston. I could unscrew the head with ease, but lacking a socket wrench for ants I could not put it back on. Who makes these things? I opted instead for an aluminium double sealed head I had lying around.

My problems with the spring guide had apparently resulted in some structural problems, since at some point during test firing the steel tooth broke off the piston. Luckily I had an old spare nylon piston with it's own plastic piston head that went in after a quick AOE fix, similar to the one pictured above.

My first attempt at fixing the trigger trolley consisted of glue and a several thin layers from a piece of paper towel. I figured a glass fibre style layer cake of material and bonding agent would result in a strong base which I could then file into shape. 

Too bad the plastic wasn't very glue friendly. The glue soaked paper held together fine, it just would not stick to the plastic hard enough to withstand the strikes delivered by the cut off lever. The same exact thing happened with various attempts made with super glue, epoxy and even chemical metal. This was one piece of engineering I was not exactly happy with. A thin piece of plastic subjected to repeated strike forces sounds exactly like a recipe for success.

Since the original plastic was a no-go, it was time to fabricate a stronger part. I chose a piece of sheet metal for the job with roughly the same thickness as the original plastic. After tracing out the shape of the trigger trolley, I cut it out, filed it down to size and rounded off any rough edges.

I drilled a few holes (with a 1.5mm drill bit) into the metal, filed down the original trigger trolley, drilled some holes into that as well and roughened up both surfaces, hoping the epoxy would finally bond well enough. I chose to make the holes canted every which way so that once the glue set, the pieces would not come off each other so easily.

To further address the issue, I cut down the trigger contacts so that the trolley would have more freedom to move up and down (the top piece is cut to shape above, the lower shows the original shape).

Everything was working pretty nicely apart from the fact I was getting triple and quadruple shot bursts on semi. The culprit in the end turned out to be my upgraded trigger trolley. The sheet metal was not as thick as the plastic, and thus the trolley was able to sit higher in its rails before disengaging. This in turn made it so that the cut off would not lift it out of place until the trigger was fully pressed down. I fixed this by epoxying another piece of the sheet metal onto the cut off and filed it to size. No more problems with semi auto! 

To round things off, I made a basic DIY MOSFET out of an IRLB3034 and some resistors. The middle prong is cut off and the negative lead is attached with a small bolt and nut to the back plate. Sturdier attachment, better flow of current.

Wiring up a MOSFET on a P90 can be done exactly like in the AUG, since the trigger assembly is the same. There's one switch and a pair of contacts for the semi, and another for full auto. It's only the movement of the trigger that decides whether the gun fires semi or full auto. On the AUG it's up to the shooter, on the P90 the fire selector limits the movement of the trigger.

All the extra bits and pieces fit in without issue and the gun was mechanically ready for service.

One final fix was to repair the cracked receiver. Since the material is ABS, you can forego glue and use pure acetone, as it melts ABS. My end result is a bit sloppy, but with an unhurried approach, slowly wicking the acetone into the crack, you can achieve a brilliant result. While mine isn't aesthetically as pleasing as it could, the upside is still that the plastic is again one single piece as it was when moulded, not two parts held together by an adhesive layer.

With an 11.1 V LiPo this little beast is pumping out 33 rounds per second at 0.92 J. Right on the money, if you ask me. Now I only need magazines that aren't hicaps and can still keep up with that.

Questions? Comments? Anything you'd add or like to know more of? I'd love to hear from you! 

Pouch Painting

If you've ever bought gear from more than one manufacturer, you've most likely been there: Colours don't match. Olive drab especially seems to be a complete no man's land when it comes to colour coordination. They're all supposedly the same colour, but when you place them next to each other, you will certainly notice they're not.

You can always go out in your non-matched set, or grab a can of spray paint and go to work. Here's a quick primer (yes I went there) on how to get your garb to match.

The picture above shows quite clearly just how different the concept of olive drab can be. The RRV replica underneath is from Miltec, and the various pouches are from Pantac, TMC, Condor and from an unbranded Chinese manufacturer.

Painting nylon is fairly straightforward, just apply several thin layers as you would do with any other spray paint project. The de facto brand that people enjoy using is Krylon for its consistency but I went with a camo colour series from my local car parts etc. retailer, Motonet.

Here's a great example of "do as I say, not as I do". I went a bit overboard with the spraying on this TMC radio pouch, and you can see the otherwise matte paint is starting to glisten on the lip of the pouch. Otherwise the result is pretty good. You can clearly see the difference between the painted part and the so far unpainted fastener on the top right. Do note that the paint interferes with velcro to some extent, so try to avoid spraying large quantities over such surfaces if you want to retain the stickiness.

Some parts, such as the crease on the pouch above can be a bit problematic if you want an even coat. You can, however, always spray and then rub the paint in with your fingers, for example.

You can also use gloves while doing it. Assuming you're not too dumb and/or excited to remember such things, of course.

Really getting there after only a short while. I'm sure the father-in-law doesn't mind spray paint on his lawn.

The end result after three(ish) light coats. The AK pouches were left unpainted to be used as reference. I left the paint to cure overnight before using the pouches.

Do you have experiences in painting your gear (or guns)? Let me know in the comments!

Battle Group Parola Milsim Event Picture Post

The second to last weekend of July played host to the biggest milsim event Finland has seen so far. Over 600 participants split into five factions spent around 27 hours in actual Finnish army training grounds and surrounding woodland trying to gain the upper hand, or simply to survive.

As mentioned the area comprised of real, actively used military training grounds

The backstory revolved around a civil war, where a monarchy supporting faction (red team) attempted to take over Finland from the democratic loyalists (yellow team). Also present were the UN, civilians from two nearby villages, and a team of mysterious operators from a foreign nation (blue team).

You don't see traffic signs like these every day!

The training grounds are adjacent to the Parola Armoured Brigade, which coincidentally is also where I received my year long military training, and the plot of the game revolved around a locked and boobytrapped underground tank hangar. Both belligerents were trying to get inside the hangar without activating the self destruct which would blow up these strategic resources. Rumours told of a former hangar foreman who had set up the explosives and thus also held the secret of disarming them.

Both sides were thus scouring the area for the foreman while also securing key crossroads and assets, trying to figure out who the blue nation were, interacting with the UN and the villagers and naturally battling each other.

My personal role in the game was sadly rather minimal, as my injured leg prevented me from taking to the field. While the rest of my team, BFN Airsoft were out in full force, I got a job at my side's HQ as a situation officer. Rest of the HQ were unknown to me beforehand, but team mates with each other, and they had the job so well in hand that I mostly tried to remain out of the way. However, it was definitely a valuable learning experience to see how an HQ is run, how they would interact with the organisers before and during the event and what the challenges are when you're in charge of five platoons with unique missions around the clock.

The view from the HQ tent. My team's tent is visible in the middle.

In addition to foot patrols, teams got around using in game vehicles such as four-by-fours, trucks, ATVs, and the organisers had even managed to bring in a real life IFV, a BMP-1!

Here's another sight you don't see every day!

In the end the red commander tried to enter the hangar, only to blow up the charges, destroying all the vehicles inside. It turned out the aim of the foreign operatives was to ensure neither side could get their hands on this strategic resource, and thus played both sides to the best of their ability.

I enjoyed my time even though I never got to see action. The closest I got was when the BMP-1 made a rush for our HQ, and we had no antitank weapons at hand. They basically ran over all our defences, and we at the HQ decided to opt for a self destruct so the enemy would get no intel. To our amazement they then proceeded to just mill around for a while, never even took a look inside the HQ tent, and then proceeded to leave us completely alone!

Good times, and I can't say I wasn't at least a bit wistful seeing my old stomping grounds 14 years later.

In order to not have a blog post that has nothing to do with teching, I present to you a fantastic field repair job I did on my Kalash/CYMA AKMS.

The L-shaped hop up retention piece had gone missing, and I noticed because of that you could accidentally remove the magazine by rocking it backwards. This was in no way ideal, and lacking proper materials I made do with what I had on hand. This worked well enough, so mission accomplished!

I'm so very much looking forward to returning to the field, so wish me luck on my recovery. I already have a new E&L AK stashed away for just that moment. I'll be doing some work on it in the near future, so stay tuned and play safe!

Plates On The Cheap

New plate carrier vests often come with some sort of foam inserts to hold the vest in shape. They're usually not very tough or rigid though, so the illusion of a ceramic plate isn't really there. To fix this, you can always buy ready made dummy plates, but what if you are on a budget? Then this quick guide is just for you.

If you happen to have an IKEA nearby, you can source some plate materials very cheaply. The LEGITIM series cutting board just so happens to have measurements that closely match the Medium SAPI plate (24 x 32 cm for SAPI plate, 24 x 34 cm for the cutting board). The thickness of a single board is about half of a ceramic plate.

The tools you'll need are a saw, a straightedge and a file or some sand paper (possibly glue). If you want to get fancy, a hot air gun or some hot water may also be in order.

To begin, take a straightedge and mark the corners of the board for cutting (the angle is about 45 degrees), or follow the shape of the foam insert that came with your vest.

Next, simply saw off the corners, and finish by either filing or sanding down any rough edges so they don't scratch and tear the inside of your vest.

If you want to get fancy, you can use a hot air gun or some hot water and bend the board to get a curved plate. Use a form, such as a piece of pipe or similar to get a symmetrical shape (I'm doing simple straight ones here).

Glue two boards together for a thicker plate, or put the board in front and the foam insert on the back for a more comfortable wear.

You'll be ready to operate in no time.

Let me know in the comments how yours turned out!

Gear Review: Invader Gear Armor Carrier and Predator Combat Pants

I'm taking a slight step away from the teching side of things for a while on this post and taking a look at some tactical gear instead.

I received a light plate carrier (simply dubbed Armor Carrier) and a pair of Predator Combat Pants for review from Airsoftzone.com, a shop operating out of Austria. Both items are manufactured by Invader Gear, a brand I was not too familiar with from before. Invader Gear is what I'd call mid level equipment. Not the low-down cheapest possible (and poorest quality) stuff you can find, but not the real world use super expensive gear either. In my mind they occupy a place where a balance between high quality and affordability is reached, which to me sounds just optimal for airsoft use.
As the company states on their own page, "All of our products were designed and manufactured to be reasonably priced while providing decent quality. We are focused on sturdy durability, proven materials and a wide range of colors & camouflage patterns." Their items are produced in Pakistan, so you can definitely expect a higher standard of quality than you can from ACM products. They also use YKK fasteners all around, so you can count on them a lot more than unbranded plastic fasteners.

How do these two items fare, then? Let's look at the Armor Carrier first and the Predator Combat Pants second.

Armor Carrier

The Armor Carrier is a simplistic, lightweight plate carrier with front and back plate compartments, adjustable shoulder straps and strap fasteners on the sides. The article  pictured is coloured Ranger Green. At the time of writing, the carrier is also available in ATP camo (a close cousin of MTP/MC) and Coyote.

The front features a hefty amount of velcro for name tags etc. and both the front and back have a PALS matrix of 5x8. The very ends of the webbing overlap the edge of the plate, so threading a pouch there might prove problematic in some cases, but width of the stitching is correct. (I've had cheapo PCs that have too narrow webbing on the edges, which is really sad). The only thing lacking is an evacuation handle on the backside. While it's not exactly an actively used function of a vest in airsoft games, it would be a nice visual addition nevertheless.

Height adjustment is done via simple velcro straps hooked around a plastic triglide buckle. I don't consider myself a huge person, but I had to pull out the strap quite a bit to make the vest sit at the correct height. This plate carrier might end up running out of adjustment for a larger operator. The straps and the points where they attach on the front and back are padded underneath, which makes wearing the vest very comfortable.

Width is adjusted via a simple strap hooked to a hefty plastic YKK buckle. The strap also has an elastic band around it for tucking away the excess end. Here, there is a lot of adjustability compared to the height adjustments, so you can definitely fit the carrier over several layers of clothes and other equipment if need be. 

A quick peek on the inside reveals a simple inside layer with brand markings and plate compartment flaps that are fastened both with snap fasteners and velcro. The undersides of the flaps have two grommets for water drainage.

The vest comes with thick foam inserts both in the front and the back, cut in the shape of actual plates. The material, while thick, is pretty supple and elastic and also quite light. The fact that the compartments are not empty from the factory, and the carrier has the correct look from the beginning, is a very nice touch. However, in order to achieve a more authentic feel, I'd suggest either purchasing or making stiffer and heavier inserts. The vest, as shipped, weighs in at a very light 625g.

The quality of the stitching and the materials is simply unquestionable. Places of expected high wear are carefully double stitched, all the lines are dead-on straight and there are no loose ends of thread visible anywhere. I am thoroughly convinced with the quality of this product and do not hesitate to recommend this to anyone looking for a lightweight plate carrier. Airsoftzone.com has one for you right here, retailing at the time of writing for 57.90 EUR.

Predator Combat Pants

I can say right off the bat that this is no ordinary pair of trousers. Care has been taken to make them fit the individual user and to make wearing them as comfortable as possible, but I can't help mentioning that if you've ever seen Crye Precision combat pants, you'll know exactly where these pants borrow (quite heavily) from. The article pictured has a camo pattern named Everglade (close to ATACS FG), but the pants are available in 14 different colours and patterns, including but not limited to black, coyote, OD, Marpat, Vegetato and Woodland and they come in sizes from S through XL (and the actual size fits the size chart exactly).

The pants have integrated knee pads, elastic sections around the knees and lower back, padded waist, 8 velcro-closure pockets and two open side pockets. The pants, like the plate carrier, utilize YKK zippers and fasteners to make sure things stay where they should. The fabric is thick and stiff(ish) in exactly the way you'd expect from such a high wear item, and is a mix of 65% cotton and 35% polyester.

The pants have a covered zipper fly and a velcro closing flap aligned with the waist to allow for some size adjustment.

The backside has a strip of elastic fabric to ensure the waist stays put when you're crouching, kneeling, bending over or crawling. Belt loops are large enough to fit a wide belt with a large buckle through with ease (pictured belt is 5cm wide).

The knee pads are a stiff, rubbery plastic, which should stand up to abuse. They are inserted from the front and secured in place by velcro sections around the cutout. Padding around the knee pad extends al the way to the edges of the insert compartment. Lowering to one knee or crawling will be as comfortable as possible. The elastic fabric around the knee pad also ensures the pants don't pull when you're manoeuvring in them.

A handy strap that runs from the inside of the side pockets to the knee pad allows you to adjust the height of the knee pads in relation to the waist, which is a brilliant way of making sure different users can make the pants fit their anatomy.
There are velcro adjustment straps behind both knees, which allow you to tighten the pants legs around your calves both to lessen the amount of loose fabric flapping around as well as to stop the pants from riding up.
Similar velcro straps exist around the ankles so you can tighten the legs around your boots or more easily stuff the pants inside them. Also note the small ankle pockets in the pictures above.

With the velcros done up the pants really hug your legs and make movement easy and effortless.

As with the plate carrier, the workmanship on the pants is superb. Sturdy, straight stitching all around with double stitches in high stress areas. The ability to fit and adjust the garment to the individual user make these the most comfortable tactical trousers I've ever worn. Like the plate carrier, these come highly recommended. You can get yours on airsoftzone.com here. Prices at the time of writing vary from 76.90 to 84.90 EUR depending on the colour/pattern.

Conclusion

I am thoroughly impressed by Invader Gear! From what I've seen on these two products, they really make good on their promise of making reasonably priced items, but the quality in my opinion is far beyond "decent", which is how they themselves describe it. The quality of materials and workmanship really put these a cut above the rest. I will certainly be looking at Invader Gear when I'm planning my next tactical gear purchases!

Drop me a line below if there's something more you'd like to know!