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CaptainSwoop

Rebuilding a pair of 'Ex Hire' Classic Army M15A1 guns

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I got a pair of Classic Army M15A1s last Sunday for £25 on the final day of Gun Ho.

They sold off their rental gear at the end of the day.

 

They have had a hard life but apart from a bit of corrosion and some scratches and cracks in the stocks they shoot all day.

 

ANyway I have started rebuilding one of them.

 

This one in fact.

 

IMG-20131021-00037_zps06d707b9.jpg

 

It will be for my Son Tim.

 

He wants Magpul hardware so the stock and handguard will be replaced.

 

ANyway I have stripped it down to it's bare components.

 

I was surprised to see that apart from some wear on the piston teeth it was all in good nick with no slop in the plastic bushings or damage on the gears.

 

Gearbox stripped, cleaned and laid out

P1013755_zps0ccc3ac0.jpg

P1013757_zpsac271676.jpg

 

I am planning to replace the plastic Bushes with Steel and also plan on replacing the Piston with an alloy one with alloy head and steel teeth.

I am going to put in an alloy Nozzle with an O Ring.

 

I am also going to put in a Mosfet

 

Any advice is very welcome.

 

 

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Stick with plastic teeth on the piston and a plastic nozzle. Metal teeth on a piston are normally tougher than the gears so if something goes wrong the piston ends up destroying the gears and not the other way round... Pistons are cheap, gearsets aren't!

 

Plastic nozzle is for a similar reason, if something goes wrong the nozzle will smash your hop unit to bits if it's metal, you'll also run the risk of chopping BBs up occasionally.

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Thanks for that, this is why I like this forum!

 

Makes good sense, best failure mode is to sacrifice the cheapest component to protect the system.

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Indeed. They had half a dozen CA guns. I got two of the older ones as I want to throw away some of the parts so wasn't bothered about the stocks for example.

Both of the ones I have got split along their top seams of the stock where they have been stood or fallen on.

Both of them are about 3 years old and they have been used by heavy handed youngsters and novice AIrsofters.

Thedu have mud dried in the pistol grip, end of the stock in the magazine openin gand inthe flash hider.

I went for this pair because Tim and myself have used them on 3 Skirmishes without a problerm so I knew they were more or less OK.

They have been running them on LiPo batteries that weren't included in the sale.

My mate with a lathe is going to shorten the barral on one of them and turn it in to a CQB for us.

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I've just refurbed a classic army spc, I do have a spare solid stock if your after a replacement for a few quid.

 

I did have difficulty wiring it to a sliding stock as the small tamiya connector was in a tricky place, I ended up having to chop it off and add some more cable via some joints in the gearbox.

 

Mine had metal bushings, the bits I changed were the piston and piston head (the one on mine was terrible), the air nozzle (be careful as the m4 one I bought was longer and caused feed issues), spring guide (as the one included looked low quality) and the tappet plate.

 

I'm going to probably change the spring, cylinder and cylinder head next, but want to chrono it first at my local site.

 

Good luck, swapping the solid stock to a sliding variant was very frustrating due to the highway pokery to get the cabling through.

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Thanks for that info.

 

As I am putting a Magpul hand guard on the front the battery will go inside it so don't have to worrky about the wiring in the stock.

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Gearbox re-assembled wih nice new silicon grease and new parts to replace the worn bits.

 

All the other parts paint stripped, washed and de-greased ready for a nice new coat of paint tomorrow.

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Silicon Grease is generic name for a wide range of synthetic products. I have a little tub of 'Silocon Grease' I use for sealing the backs of Watches with screw down backs and Crown. It retains a thick consistency.

I also have a tube of 'Silicon Grease' that is nice and slippery for bearings etc.

Important thing about it is it doesn't thin when it gets warm or thicken in the cold

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Silicon Grease is generic name for a wide range of synthetic products. I have a little tub of 'Silocon Grease' I use for sealing the backs of Watches with screw down backs and Crown. It retains a thick consistency.

I also have a tube of 'Silicon Grease' that is nice and slippery for bearings etc.

Important thing about it is it doesn't thin when it gets warm or thicken in the cold.

 

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All apinted and re assembled. Pictures tomorrow.

 

One is rebuilt as standard the other has a Magpul Stock, Hand guard and shortened 'CQB' Barrel.

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gun2_zps14579022.jpg

 

This one is rebuilt in 'CQB' style.

 

I have to re-wire to the front for the battery or maybe even in to the stock tube, a LiPo will fit according to the measurements I have.and the stock has a snap on cover at the end to allow access to a battery.

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On both models I stripped everything down to individual components.

Renewed small parts like screws, circlips and pins if they were rusty

Washed everything in warm soapy water then dried and left in the airing cupboard for a few days.

De-greased with Isopropyl Alcohol and sprayed with various black paints to give different finish depending on the part being metal or plastic, for example the Stock, hand-guard and pistol grip are more satin than the metal parts. I got a satin finish with a smoother surface on to the barrel compared to the receiver.

 

I had to do repairs on the solid stock. One of the two was quite badly mashed and held together with black gaffer tape. This one was discarded and replaced with the Magpul stock. I repaired the better of the two which was just split along its top seam. I used epoxy in the split and backed it with a plastic fillet also fixed with epoxy, it is now stronger than ever and the repair is invisible.

 

As the Classic Army outer barrel is in two parts, the end that fits into the receiver is separate I was able to shorten it to make the CQB version. This joint is held together with grub screws two on top and one under. While it is solid in the vertical plane it does allow for some sideways play so I fixed it with an epoxy and it is now solid.

I did the same with the joint in the 'standard' rifle

 

Magpul parts were sprayed with Halfords Khaki which I have to say is a lot lighter than I expected but my son likes it.

 

I am going to replace the Gas Block and foresight on the CQB version with a flip up version and remove the top handle in favour of a Holographic sight and flip up iron sight.

 

I think I might put a Magpul hand guard on the standard rifle as well, I like them :)

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Thanks.

I still have some work to do.

I have a gas block with built in flip up sight for the black gun and a flip up rear sight to go on it.

I have some rail covers on the way as well.

 

I want to do some more work on the gearboxes and put Mosfets in to them to allow higher voltage and up the ROF.

I want to put tighter barrels in as well.

 

The black gun houses it's batteries in the stock, it takes an 860 mah Lipo perfectly in the Stock tube.

The other one houses a 1600 mah Lipo in the handguard.

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Starting the last phase.

Both guns have problems with their Semi Auto. In that the ydon't have any.

I have had the gearboxes apart again and identified the problem.

Both have some wear in the trigger switches and cut off levers.

On the side of the switch 'shuttle' is a protrusin that the cut off lever engages with to lift the shuttle and pop it over the top of the trigger. This allows the spring to pull the switch contacts open cuttin of the circuit and giving semi auto.

 

I am replacing the cut off levera and switches. This will cure the problem.

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