I have been lurking around the forums for a few years and have built both an M14 EBR-RI and a M14 DMR using stock Cyma CM032 internals. Both have been sold in the last 2 months and I was looking for a new type of project using a Cyma M14.
I realized that during my research that there a very few if any actual facts about upgrading the Cyma M14. However, there is a huge quantity of "My girlfriend's brother's ex-boyfriend's hairdresser says that that product is crap and won't work in a Cyma M14."
Moreover, they don't give any more information so a person could make an informed decision.
Most of you have read enough "reviews" to know that a significant quantity of reviewers do not possess the information to allow a person to have any confidence in the reviewer. Words like "neat," "sweet," and, "fer schizzle," don't convey much information to tech your M14.
Therefore, I started thinking about what I would like to find out and just go from there. If anybody else gains knowledge, that is not a bad thing.
So there will be two phases to this journey. The first will be what I can do with just the basic recommendations included in most teching guides such as this one and others like it on other forums.
These guides include a wealth of excellent information about how to upgrade the performance of your gun, IF you are willing to read the guides and actually do the work that is involved.
I do want to point out that I am a cheap person. I have always felt that if I put my own labor into a project I can save money.
We will see.
I will be concentrating on the hop up and gearbox units mostly. I also have a variety of battery types, which can also yield information. I have not opened the gun yet so that I can get some baselines for different battery types.
I had originally purchased a FiDragon chronograph for cheap reasons. I was wrong. The FiDragon chronograph is a waste of time because the tube that you shoot through is of an unsuitable material and will be blown out by even low fps spring pistols after just a few rounds. This is the input cone to shoot through:
I tried to fix this using aluminum flashing to line the ramp so the pellets would enter straighter. This is what happened to the tube that carries the sensors.
I tried using a piece of PVC pipe to make a new tube but when that didn't work I lost interest in wasting more time with FiDragon.
If a grown man who is trying to be careful cannot shoot straight enough to suit the manufacturers of this flawed item, perhaps they need to reconsider their design or I need to reconsider chronographs.
I did some research and decided to purchase an Xcortech X3200. Clandestine seemed to have the best price and I ordered it Christmas day evening (Thursday). They shipped it Friday and I arrived here today (Monday).
Kudos to Clandestine for their efforts.
I have four different batteries that I am trying and three different chargers:
A 1100mah mini NiMH 8.4v
A large NiMH 1500 mah 8.4v
A lifepo4 12.8v 4s3p concoction that I made up before I knew that the output amps would only be around 1-2C, but I will use anyway
A lipoly 11.1v that I just purchased from a megastore along with a cheap charger, but it is a 20C output so let's let the sparks fly, so to speak.
All batteries have been converted to clone deans as will connections in the rifle.
The rifle was purchased from the same megastore as above, is said to be a V-POWER, and is supposed to shoot around 400 fps right out of the box-we'll just see about that, won't we.
Mini NiMH: 310fps 11.8rps
Large NiMH: 300fps 11.7rps
11.1 lipo: 415fps 16.9rps
12.8 lifepo4: 390fps 15.3rps
This is straight out of the box, batteries fully charged.
For the time being, I will only be giving feet per second and rounds per second numbers. At this time, I have no way to check accuracy by target shooting outside. I don't have the room and its 10 degrees F outside. Hopefully in the future, as it warms I will be able to find a place to target shoot out to 300 ft. If anybody around HWY 370 and I-80 south of Omaha has any ideas just let me know.
I hope to start on the gearbox tomorrow-wish me luck
I used this guide for disassembly.
To remove the bolt catch described after scope mount removal, just use a pin punch from the front to push the pin holding the catch towards the back. You only need to go about 1/4-3/8" towards the rear before you can remove the pin. Be aware there is a short small spring just under the catch. Do not let it go flying across the room.
BE AWARE: When trying to remove the upper receiver, there is an unmentioned screw.
Remove it now.
Continue following the guide until the gearbox is separate.
I will now switch to a video guide.
At 1:43 there is an unmentioned screw holding the safety lever on. Don't miss the spring on the backside.
After getting the gearbox apart just clean up with solvent.
The piston has a steel first tooth. The spring guide does not have a ball bearing, but does have two washers that allow the spring to rotate. There are no washers or bearings on the inside of the piston
Polish piston grooves on inside sides of the gearbox, polish cylinder inside.
Time to shim.
I used this guide, and after shimming, turned to this guide then used this guide to check compression and this to double check.