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mrpenguin

Building my DMR and need help

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I recently bought a used CYMA Full Metal M16A4 RIS DMR

The gun seems very loud and even though its suppose to shoot at 430FPS (according to the manufacturer) it does not get the same reach as my M4 that shoots at 350FPS

My BB's also seems to curve really bad and accuracy is super bad.

 

I am assuming either something is wrong or the inside parts are just bad quality.

I think my best option is to replace as much of the insides as possible to get my DMR to be the best that it can be.

 

Full Metal V2 gearbox with a 509mm 6.05 copper barrel.

 

I have spend hours trying to find what parts are the best to upgrade my DMR but for every website I find that says this and this parts are the best I find one that says those parts are garbage and to stay away from... so I am completely lost.

 

Please help me with what are the best parts to replace with.

I am looking for long range accuracy as I would be playing as a sniper in full ghillie suit with this DMR with other weapons for close combat.

 

I am assuming the first thing to replace would be the barrel and hop up but again I cant even find a website that can give me a definite answer on if it should be a tight bore or wide bore barrel.

 

I will also modify the gun to shoot Semi only so I am looking to be able to shoot at 450 FPS

 

Thank you!

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Prometheus is the most common brand for upgrade barrels as they produce high quality barrels that aren't too expensive. PDI and Edgi make even better barrels, but are obviously more expensive. In my experience it's more about quality than inner diameter, but the general consensus is that you don't want a really tight barrel for long range accuracy. If you want to replace the hop-up unit Prometheus is a popular brand there as well, with Lonex as a more affordable alternative that is still high quality. When it comes to hop-up buckings it's pretty much the same story there with and addition of the well know G&G green bucking and Maple Leaf buckings also seem to be quite renowned. You should look into mods like R-hop and Flat-hop to maximize range and accuracy.

 

When it comes to the gearbox itself the stock shell should be sufficient if you radius the cylinder window. If you prefer to replace it I can highly recommend G&P gearbox shells, many prefer Lonex gearbox shells, but I don't like them for various reasons. When it comes to the drivetrain (gears and piston and such), SHS is generally a good choice if you don't wanna spend too much. If price isn't an issue you could take a look at Siegetek gears. I can personally recommend Lonex when it comes to air seal parts, I've gotten very good results with their air seal parts. An M130 spring should put you close to your FPS goal with good air seal, but you may need to use an M140 to reach 450fps.

 

I'm not very experienced with DMR's, but the one DMR I built I powered with a 14.8V li-po combined with a high TPA motor and low ratio gears to get maximum trigger response. A good 11.1V li-po is probably sufficient though, I tend to overdo things. A popular motor choice is the ZCI high torque, it's cheap and has plenty torque, my personal favorite is the Guarder Infinite Torque Up, both will get the job done nicely.

 

You should google "The holy grail of DMR" to find a full guide on DMR building.

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Your not using a good platform for a DMR.

 

Replacing "everything" inside is a NEW user mistake. The cost of replacing everything inside would be the cost of a GOOD AEG and not a CYMA.

 

You should buy an AEG that is partially designed to be used as a DMR and tweek from there...NOT rebuild.

 

Check that your hop-up packing is centered and clean.

 

Clean your barrel with a solvent (NOT oil) and then try shooting again. CYMA AEG barrels are very dirty brass (did you swap the barrel already) and not copper. No one makes copper barrels anymore (used to be a chrome CU barrels back 15 years ago...but no more)

Edited by Guges Mk3

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One can use an MP5 as a base for a DMR in airsoft, gun design is irrelevant, it's the parts and tuning that matters. I do agree that a CYMA M16 may not be the best starting point for a DMR build, but OP already has this gun and has decided to upgrade it. I've built high performance AEG's out of lower brands than CYMA, it's all about the right parts and enough elbow grease.

 

If I were to build a serious airsoft DMR I would most likely base it on a high quality AK variant, would probably go with an AKM.

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By the way, rubbing alcohol is an easy thing to clean your barrel with, if you have your cleaning rod, use that with a piece of paper towel wrapped in the slot, twist it and push down the barrel all the way, keep doing it till the paper towel piece comes out clean.

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Thanks for all the info so far!!!

So I opened up my gearbox to clean it out because the gun was very loud, once inside I saw all the gears had A&K marking on them .... so I guess my gun is not a CYMA but A&K, don't know if that makes any difference or if these guns are made in the same factory?

There are no marking on the outside of the gun at all.

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Don't believe what you read. It could be A&K it could be A&K gears in a CYMA.

 

There are about 4 "official" makers in China. Of those 4 they support 10 brands. A lot of mixing and matching is going on behind the scene.

 

I have this picture on stock a lot. I know a lot of "inexperienced people" that just gush about SHS...but SHS sources their parts from the same "pool"

 

26705583554_5dc1fd28fc_b.jpg27312759085_cd8523acbd_b.jpg

 

Also if you look at SHS Gears, Shooters, Ares, Eagle Force, AF and about 6 more. The gears are the same.

Edited by Guges Mk3

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I got some advice from friends, I am going to replace everything inside and I was told that I need to replace my stock gearbox with a Lonex SP140. The problem is that I can not find anybody in Canada that has one of these in stock.

What would be my next option for a drop in gearbox for me to shoot at 450FPS in my DMR ?

 

I would prefer not to buy only the shell and then build the entire gearbox since it will probably cost me over $100 more.

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These friends...I would not listen to them.

 

If none of them has less than 10 years of direct hands on experience...they know not of what they speak.

 

Because I can tell you from direct experience. the Lonex gear box will not fit. Specs are off in holes by .5mm and the back needs grinding to get it to drop in.

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Radius the front corners.

 

Do Airbornes101 Mods and put in a M130 Spring with a Tienly GT35K Motor.

 

Maple leaf Packing and nub

 

That is all you need. for 80M Head shots with .28g bbs all day.

 

All on a 2S Lipo battery for consistency.

Edited by Guges Mk3

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Save yourself some money and go with an SHS or ZCI high torque motor, the Tienly won't offer any better performance and is nearly twice the price. I have a Tienly GT35k myself and it's a bit disappointing to be honest. It's not a bad motor, but definitely not worth the price, my SHS/DA motors rivals it's efficiency and are at least as durable and are about half the price. A middleground price wise would be a Guarder ITU, the pinion is a bit on the soft side compared to an SHS, but I'm very pleased with the performance with the one in my M4.

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While I look on the positive side of a Tienly. I admit the new price levels of 60.00 is still rather high. Yet get a consistent QC and certain HQ motor.

 

However, the exact opposite issue is true for SHS or ZCI. The motors are made in china in "batches". One great batch will run out and the next batch is suspect or not as high performing. In the US this is indicative of a downward trend for the "popular" low cost motors.

Edited by Guges Mk3

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A drop in for an A&K?

 

Another A&K, Kings Arms of JG would be no issues.

 

However, if this is your only AEG...don't be like other new players. Get a functioning AEG and use it as a primary. Then get "another" AEG and mod that one to your desires. Then when it fails you can go back to your primary stock AEG.

 

I can say this from personal experience that I will always see one kid sitting out the rest of the day after a few rounds because their only "modded" AEG failed on them.

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What do you guys think about this Gearbox ?

Matrix M150 rated for up to 550FPS, I would obviously change the spring to shoot 450FPS.

 

Will this hold up ??

 

Here are the specs:

Matrix / AIM Lipoly Ready 8mm Complete Gearbox Set for M4 / M16 series Airsoft AEG (Monster Torque) - Wiring to the Back / Stock
*Motor Not Included / Sold Separately. Recommended Matrix Magnum Motor.

Manufacturer: Matrix Tactical Systems. OEM: AIM. Matrix is the exclusive US Distributor for AIM Products.
Compatibility: Tokyo Marui, Classic Army, Echo1, JG, G&G, G&P, Echo1, DBOY, SRC, A&K, KWA and compatible models. Modification might be required for certain brands.
Matrix Tactical Systems Gearbox Models : Available in Monster Torque and Tornado High speed. Front wire and rear wire.

Specifications:
- Systema / G&P / Classic Army Type 8mm Enhanced "Thick Type" Mecha Box Shell.
- M150 Spring. Velocity out put for this gearbox is around 480~550 FPS.
- Low Resistance / High Capacity / High conductivity / Wire & switch assembly Set.
- High Grade 8mm Metal Bearing Set Installed. Providing enhanced stability over the 6mm and 7mm gearboxes
- Ball bearing CNC Stainless metal spring guide.
- Matrix Ultra High Performance High Speed Piston with Metal full teeth strip.
- CNC Stainless Steel Cylinder Head.
- Reinforced Silent Polycarbonate Piston Head.
- Steel Gear Set
- Reinforced Nylon Smooth Selector plate and tappet plate.
- Reinforced Ball Bearing Polycarbonate Piston Head.
- Reinforced Matrix Monster (Torque Up) Gear set Installed.

 

http://www.evike.com/products/30443/

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AIM is not a brand to be proud of. Matrix is a Evike rebrand and the stuff is not good. There are many dumb or redundant parts in this build for a HP Mechbox.

Plus that fps rating is entirely subjective to barrel length. Drop that mechbox in an AEG with a 250mm barrel and you may not even break 400fps.

 

Plus these things are a bad sign:

- High Grade 8mm Metal Bearing Set Installed. Providing enhanced stability over the 6mm and 7mm gearboxe

You don't want BEARINGS in HP build. You want bushings.

- Reinforced Ball Bearing Polycarbonate Piston Head.

- Reinforced Silent Polycarbonate Piston Head.

It has two piston heads? Not a good sign. Last two headed piston AEG I saw didn't work very well.

 

- Ball bearing CNC Stainless metal spring guide.

- Reinforced Ball Bearing Polycarbonate Piston Head.

 

If both of these items are installed...it is very wrong. You only need 1 bearing set not 2. That is if you need any at all.

- Matrix Ultra High Performance High Speed Piston with Metal full teeth strip.

Full rack HS piston is NOT want you want in a HP build. The weak mounting point on the back will blow out rather shortly.


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