Colt Python X-Cartridge

[renegadecow]

A Colt Python featuring the X-Cartridge by Marushin doesn't actually exist. Pictured above is a KWC Python modified to fit Marushin .45LC (SAA) X-Cartridges. Below I'll be discussing just how that's done and what improvements it gives.

 

I've had my KWC Python on a shelf for a long time now after a couple crucial internal parts had broken. To those unfamiliar with the gun, it's a Taiwanese copy of the Tokyo Marui Python with the same 24-shot system only they made the shells removable. While 24-round capacity sounds pretty handy for a wheel gun, it's because of this system that it has poor power output even with longer barrels. The gas, already having traveled a long ways from the valve in the grip to the base of the shell, has to squeeze through the shell system and the bbs loaded in them. On propane, my 2.5" Python can barely push 200fps on a hot day.

In trying to repair the broken parts (one was trigger related and an easy fix) I decided to experiment on upping the power of the gun by rechambering it to a different set of shells. The other part which broke in my gun is responsible for delivering only one round down the barrel even if the shell is loaded with four. As the trigger is pulled, the hand pushes up against a cam which pushes the top-indexed shell forward. This seats the front most loaded bb and locks the rest behind it so that when the hammer is released, the gas will only propel one bb. With mine broken, it will launch all the contents of the shell and at such low power, you're looking at sub-100fps per bb.

 

X-Cartridge left, KWC shell right

 

I looked at Marushin's .45LC X-Cartridge as the replacement shells. Oddly enough, the case would actually fit really well in the .357 chambers. I had suspected long ago that the Colt SAA Marushin had based their replica on was a .357 or .41LC and merely stamped ".45" on the side of the barrel. The only problem is that the front of the cylinder is necked down and the relief for the case rim slightly too narrow so the shells won't truly fit. The solution was simple enough: bore out the front section of the cylinder and enlarge the relief in the back. A Dremel would be handy but an electric drill fitted with a cutting disc or sanding drum will also do the job.

 

Screw holding crane assembly to frame. Remove screw, crane and cylinder pull out (when open)

 

Crane pops out from cylinder freely.

 

Undo screw in middle to remove extractor star. Chambers already bored out.

 

Relief for case rim enlarged.

 

Chambered X-Cartridge shells left, compared to KWC shells right. Material required to remove is small, like less than 0.5mm radius.

 

With the shells fitted, you're pretty much good to go if nothing else is wrong with your gun. But mine has a broken cam and will not push the shells forward. It just so happens that the part pushing the shell is also a gas route so there's a gap between the back of the shell leaking out gas. I had to put a shim on the part to close the gap as much as possible without putting too much pressure that it impedes cylinder movement.

 

1 - plastic shim cut from a plastic folder to bridge the gap. 2 - broken cam pushing the shell forward

 

As a result, the prettier shells are used which are also much heavier and readily available. The X-cartridges are also easier to load having tapered replica slugs. The power output is also dramatically increased. I haven't chronoed it yet, but visual estimate is that it's now doing 280-300fps and can easily put all six shots in an A4 paper 10m away. I'll be providing actual numbers as I get to test it further over the weekend.

[TerranCmdr]

Nice work! This has made me really want a revolver.

[Yuri]

This is a really elegant mod. It's great when something works out so well.

 

I remember those KWC Pythons being a pain. It's a complicated gun, lots of thing going on at the same time.

 

A friend of mine had one maybe ten years ago. It broke in exaclty the manner you described, it would fire out all the bbs in a shell at once. He took it to the local store and got it back in pieces with an explanation that "it would cost more to fix it than to get a new one". Basically the guy at the store couldn't figure out how to put it back together and came up with some BS.

[jv83]

Nice project. I have seen a couple of these broken as well mainly the sear that rotates the cylinder. Renegade have you had a look at the barrel assembly? The models I have seen have had the inner barrel with quite a large outer diameter. Otherwise one might switch these with a better TB barrel.

[renegadecow]

Thanks! Really intended this mod to pass time while deciding on what new revolver to get but turned out pretty handy putting an old paperweight back into service. I imagine a lot of KWCs are gathering dust and could use some sprucing up with this mod.

 

@jv83

Popped out the barrel assembly again just now and OD measures 9.00mm and the hop rubber is flush. TM standard barrels are 8.30mm, but with the hop rubber on just might fit.

[Romulus]

Really cool idea. Its always great to see what people can pull off.

 

I look forward to actual chrono results.

[renegadecow]

Something's not right. Despite my earlier visual and physical (shot myself in the gut) comparison for an fps estimate, it only chronoed 237fps average with propane and .20g bbs. It's still more than what it originally did with the KWC shells at about 190fps, but I was expecting it to be more. Although the marshal who owns the chrono did tell me that his was being buggy lately so it may not be reading accurately anymore. But still, that's not too bad considering my Detonics just about does the same and with a slightly longer barrel. The TM Python of which the KWC copied theirs off does about 240fps for the shortest barrel and around 270 for the longest one. In theory one should get a range of 280 to 310fps if this mod were applied to them. Tokyo Marui are re-releasing their S&W M19 Combat Magnum line adding a new 2.5" barrel variant plus a new full line of M66s, the stainless steel counterpart. I'll likely get the 4" M19 myself when it's out and see how this mod fares with it.

[Dagonet]

That is an excellent picture of the inner workings and gas router.

 

I am waiting for the new M66 range as well, maybe just maybe TM will have reworked it or use higer grade materials. Still thats a good clear shot of the workings and that makes me happy RC .