Modifying the TM Mac 10 for a Lipo

[sacairsoftsn00py]

There's a handful of guides out there as to how to take apart the TM Mac 10 so I wont bother going into it. Most of the time, pictures will do the job more than explaining things in detail. So I'll post some pics with a few words.

 

 

Removed a couple of the guides for the charging handle mechanism. What they function as on the stock setup is that they just guide the proprietary 7.2v 500mah nimh battery into the connectors for it. Removing the two guides (which form a concave) allows for more room for a lipo. Do note that I cut a piece from one of the guides and screwed it back into place to keep the tension spring for the "bolt"/ hop window closure from accidentally popping out.

 

 

Dremeled off the curvature that goes to the left of the gun (with the gun pointed at you). This allows for more battery space.

 

Note where the new wires are placed.

 

I yanked out the copper connectors as they served no function.

 

 

The wires from the motor that had a "motor connector" that slips into one of the copper battery connector was yanked out. Its a red wire that goes straight to the positive end of the battery so I now had a solid line.

 

The wires that connected to the fuse are red in color. However, it is for the negative end of the battery. The fuse was yanked out and so was the wiring attached to it. There is a soldering point under the battery bay (you remove the battery bay by extracting three screws). I simply de-soldered it and soldered a new set of wiring.

 

Now I have two solid wires that are soldered onto the system and then onto the battery connectors.

 

As shown on the picture, I'm using deans ultra plugs.

 

 

End result is a clean looking job. The Hyperion 7.4v 850mah 25C lipo fits in there perfectly with the connectors tucked into the side. There are no pinched wires anywhere.

 

 

 

After charging the battery up...here's where I topped off at:

 

FPS has been like that since I got it used from someone off of ebay recently. With the piston all the way forward (as well as the nozzle), blowing into the inner barrel revealed no air leak. Its possible that the gun will need its piston head o-ring stretched, or re-lubed. Its also possible that the spring got stored in a compressed state (as the person I bought it from said he only shot it a few times then stored it in the box). Regardless, I have placed a nine ball spring for it. Off of a TM MP7 AEP, I have gotten about 270 FPS out of it.

 

I opted for that spring for a few reasons. Number one is durability. Sticking in a "300 FPS" MAG 130% spring might prove to be too much for the gearbox shell. Everyone has heard of a few accounts of it cracking and quite honestly...I don't want to have to deal with that. Secondly, a stiffer spring will require a new set of gears, possibly a damper piston head, and metal bushings. Those add up and I'd like to keep my cost-performance ratio as low as possible. Thirdly, 20 RPS is too fast for the hi-cap magazine to keep up with. Before the battery was fully charged, the hi-cap mag was feeding up to 18RPS. When I charged the battery all the way...it was shooting 9 RPS with the hi-cap mag. The midcap fed reliably on a full charge however. The extra spring tension should drop the ROF some to allow for more reliable feeding on a full charge.

 

In the end, the nine ball spring increases the FPS, lowers the ROF for more reliable feeding, maintains a still quick trigger response (it gets slower with an even stiffer spring), wont wear down parts and the gearbox shell as quickly.