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Discussion Starter · #1 · (Edited)
Project: Total rebuild of M16 DMR --Updated 6/3-2012--

Hey fellas!

First thread in this forum and im from sweden so excuse my poor english.







Well it all started about 10 years ago, bought my first CA M16 and it was
all busted up 2nd hand when i bought it, gearbox was completely shot off
in the front and the first thing i had to do was to dive into the world of AEG's!

good thing because i learned a few things along the way and ive had a passion
for the DMR role since i started playing airsoft. bolt's in all it's honor but being
in the group taking out targets further back than my team can reach is intense!

Current setup is an ACM metal receiver with skullfrog-markings and a fullstock
wrapped in carbon fiber-wrapping foil, standard M16 outer barrel and a 12"
front freefloat ris, home-buildt suppressor and some lathed parts between
the freefloat and the suppressor, i know it's far from RS but i like the look.
part from that there's a pretty standard foregrip and a bipod, Tasco 3-9 40mm

Internals:

Guarder 650mm 6.02 (mind you it's 6 years old.. i didn't know better)
MODIFY Torus 8mm reinforced gearbox
CA 18:1 gears from early stoneage
SHS M160 spring
Energy full metal-teeth piston
Systema bore-up kit (getting preeeetty damn old..)
ASCU V1
Madbull hopup unit/rubber
some noname ball bearing spring-guide
11.1V 4200mah 35C constant 75C burst.
noname China engine that outperforms the old trusty MAGNUM -it has no markings
but it's one HECK of a motor!! - wish i knew what it was lol..

guess that's it..

modifications done to the internals:

everything is polished.
gears and bearings are worn in under water for 24 hours without cylinder nor spring
but WITH the tappetplate installed - helps keeping the gears stable
and contacting in the right direction (language..) Makes an incredible difference
in both noise and durability! - i do this after every re-shimming.

tappetplate is rounded off to minimize contact surface inside the gearbox
nozzle front is lathed to a more shalow angle to better penetrate the hopup
rubber. the tappetplate itself has had about 0.6mm removed from it's front
to alow better penetration as well

using a stronger spring for the tappetplate to ensure constant power towards
the hopup each shot helps ALOT in both FPS and overall consistency +15m/s
compared to standard nozzle-shape and standard tappetplate spring.

flat o-ring lathed down from an oversized Oring made from a harder compound
to rely less on pressure-expansion and more on constant sealing (still low friction tho)
- playing around with O-rings has been one hell of a trip!!

i dont know what more to say.. part from all that work resulted in...
well a heckofa rifle, when it worked... now it's .. a bit broken shall i say?

Gearbox smashed it's front to bits and im quite surprised because i've heard
other people run M170 setups in their modify-gearboxes without problems..

guess i've must have gotten that monday-ex that shouldn't have left the factory
in the first place..

as i said, have no pictures really on this computer so this is just a buildup and my
starting point to start fiddeling around making this the best DMR i've done so far.

loads of changes are to be done to the barrel and the hopupunit and so forth
i know now from reading the forum that THIS is the place to be when it comes to
these kind of builds!

Take care and to be continued, with pictures and results, videos and comments.
 

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That is a very sexy gun, it nearly makes me want an Armalite!

It sounds like a really sweetly ran gun and it's a shame it's shattered it's Gearbox! But I must ask, how does running your gears underwater for 24 hours help? And can you (or somebody else) link me to an in-depth article (or forum discussion) on the subject!?
 

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That is a very sexy gun, it nearly makes me want an Armalite!

It sounds like a really sweetly ran gun and it's a shame it's shattered it's Gearbox! But I must ask, how does running your gears underwater for 24 hours help? And can you (or somebody else) link me to an in-depth article (or forum discussion) on the subject!?
Its an old technique we used to use to break in our motors and gearbox bearings in R/C cars when I used to race them semi-profesionaly, an alternative is to use a battery that puts out about 3volts for the duration of its charge.

It basicaly polishes the contact faces on everything that makes contact with each other without over heating, and thus bluing, them.
 

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It's called work hardening. I've also read a few guides which talked about work hardening however none of them did it underwater.

The reason to do it in water is because the water acts as a lubricant and coolant.
 

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I can understand why the work hardening would have a positive effect on the gears, I will be trying that the next time I re-build my M14.

I'll also try this running the motor underwater business too, but I must ask, does it have any negative side effects? (Such as shortening life span, etc)
 

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Discussion Starter · #9 ·
wow! im away for 2 days and BAM 6 posts!

well first of all thanks for all the positive comments! i was affraid you guys
would be too RS-hardcore to enjoy a carbon pimped fat-piped armalite but
i guess i was wrong =)

//start wall of text.

__________________________________________________________________
Work-Hardening your gears.

Yep it's called work-hardening and is done to most industrial transmission-setups
before it sees proper resistance. If you buy a new lathe or milling-machine with a proper
gearbox it is standard procedure to let the machine run in mid-RPM for several
hours before you actually start using it.

Doing it under water does not only act as a lubricant and coolant, but helps to rinse
off any particles that tends to stick to the newly polished surface and thus totally
messing up the "grinding" process of that particular surface at that revolution.
Doing it in water also helps the gears to get some resistance making the
contact surfaces always facing the right way, which is a better method than
shimming one gear a bit tight for the same reason.

when done, replace the water and let it run for 5 mins in clean water with some soap
then replace the water again and let it run for a min or 2 in regular clean water.

I did this using a couple of 8.4V batteries making sure i don't reach too high rpm's,
the water allows me to use higher voltage than the 3-4V range one would normally use.

A good tip is to add a couple drops of regular dish-washing chemicals to get
rid of the surface-tention, that way it really gets in and removes all kinds of crap.

Once you do it in water you realize why, when you see the water turning grey
even tho the motor might not be fully submerged hehe..

Workhardening your gears is a GREAT way to make sure the gears run smooth and quiet,
not to mention that once you work your way through that surface-hardening reaching
the core-hardened steel that lies beneath you really are ending up with some proper hard gears!
- Ever wondered how the grease allways turns grey in gearboxes?.... well there's your answer =)

after i polish the gears and then workhardening i can open the gearbox after a season
and the grease is still white and transparent.

------
Running in the motor under water should only be done if the motor is brand spanking
new or if you have replaced the brushes, this should be done with lower voltage 3-6V.
Basically what you want to avoid by running the motor in under water is arcing and
chipping when the brushes are still flat, it really doesn't do anything else to the motor
besides maybe giving the bearings a good workout before actually seeing any
load, however i doubt that makes much of a difference to the reliability of the bearings.
________________________________________________________________________

//End wall of text.


Thanks a heap for showing interest!

In it's current state, using the bipod and with proper hopup-settings (as good as it could get)
i was hitting mansized targets at about 240 feet with 9 out of 10 hits.

i have no real experience of bolt rifles so i dont know if that's good or not considering the time
spent on the gun but i was happy with it for a while.

i do however feel a proper Hop-up construction is needed and that's where my next project
starts!

A new Bore up Cylinder with no scratches and some slight modifications to the pistonhead
and then cutting the barrel and enlarge the window for a proper contact-patch and dual-adjustment
and what not.

Pictures will ofcours be uploaded, i do however have a couple of other jobs to finish first
feels like half of this towns airsoftcommunity has landed their rifles in my basement for an overhaul
so im pretty smacked with work atm.

I'll keep you updated!! - let me know if you have any questions =)
 

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You should try out the ER-Hop; it would most likely boost that range out to close to 300 feet with heavy ammo. Some have trouble doing it, but if you've done all those upgrades above yourself, then you'd have no problem doing it.

The one thing that I personally think would make it look even better would be a stock pouch to store the battery.
 

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Discussion Starter · #11 ·
to be quite honest with ya, that is sort of what i have been doing -i know my way around the gearbox and mechanical stuff in general but i havent stayed updated when it comes to hopup-modifications, so i just started cutting in my barrel, doing what i thought is a better way of constructing a hopup, so i took fuel-line rubber wich had a 6mm inner diameter and sanded the outer diameter down to the same outer diameter as the barrel, after that cutting a patch matching the elongated window in the barrel. im now working on rebuilding the hop up unit with 2 screws that ajdust the front and rear part of the patch in fine increments..

Had no idea there was a name for it, i was like !OOH ER-Hop! i haveto check that out... turns out it's exactly what im doing.. hehe
 

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I will advise you that while the dual screw adjuster is good, they are an absalute arse to set up and get running and balanced in cohesion.

I've been running a dual screw, long hop in my EMR for about 6 months now and I'm still not completely happy with it, though it is a marked, and not to mention, more stable, solution over the single central screw.
 

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to be quite honest with ya, that is sort of what i have been doing -i know my way around the gearbox and mechanical stuff in general but i havent stayed updated when it comes to hopup-modifications, so i just started cutting in my barrel, doing what i thought is a better way of constructing a hopup, so i took fuel-line rubber wich had a 6mm inner diameter and sanded the outer diameter down to the same outer diameter as the barrel, after that cutting a patch matching the elongated window in the barrel. im now working on rebuilding the hop up unit with 2 screws that ajdust the front and rear part of the patch in fine increments..

Had no idea there was a name for it, i was like !OOH ER-Hop! i haveto check that out... turns out it's exactly what im doing.. hehe
The standard size is called the R-Hop, but when the barrel window id elongated, it's the ER-Hop. I think the elongated window would work best for your rifle because you'll be able to take advantage of sending heavy bbs way out there. This isn't the first time I've heard of somebody doing something similar to the R-Hop without even knowing about it.

Where did you get the fuel-line and does it work well? I'd rather mess around with something cheaper before buying the actual R-Hop.
 

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Discussion Starter · #14 ·
yeah well im having some ideas about using a thin spring-metall plate that goes along the patch, resting on top of the barrel on both the front and rear part of the patch, and then use a single screw in the middle of that springsteel-peice to get a smooth distribution of the pressure over the whole surface... any ideas on that?
 

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I dont think you'll get the result your after using that system, it doesn't give the aggressive 'pop' to the bb that a normal system gives or the long, softer drag up to speed that a long hop gives.

But the only way to really find out is to try it and compare it with either a standard hop system or if your willing to do it an long-hop system of some description that maintains the same level of hop in a linear line.
 

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It's called work hardening. I've also read a few guides which talked about work hardening however none of them did it underwater.

The reason to do it in water is because the water acts as a lubricant and coolant.
I also apply work hardening to my GB builds.

I use a 4.8v 700mah NICD r/c controller pack for the process.After I get the gears shimmed,I run the gears and nothing else in my GB for three one minute intervals,with one minute in between intervals.By the end of the third interval,ussing a torque or super toeque motor,the r/c pack is completely dead.

I've found it seats the gears nicely,and really helps in reducing the noise signature of the GB associated with flat cut gears.

This is the second Torus GB ive read about that suffered this fate.The first wasnt radiused and had succumb to the fate of V2's that havent had the front of the cylinder window radiused,or sorbothane used.Did you do either of these things to your GB?

Your parts list looks good,but if I were you I would reconsider ussing SHS springs.I have read posts else where that state SHS springs cant be relied upon to supply the power there sold to put out.Simply put,if one were to buy an M120 spring,it could perform as an M90,or an M90 as a M130.I have no first hand knowledge,its only what ive read.For a build like this I would use a PDI 300%.With good compression,and air management you could be very close to 550fps or more,esspecially with that inner barrel you have.

For range I would suggest an EDGI 6.05mmX509mm inner barrel.They are simply outstanding in all categories.I have one in a CA AR-10 chronoing at 548fps(with .2's) and with a conventional hopup setup im able to reach out to 80M+ ussing .3's.If you combined one of these barrels with the long hop you want to do,you could have the potential for a very far shooting gun.
 

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It does not because the voltage you are running isn't high enough to transfer through the water. Also, when you are done you have to flush the motor with a cleaner to make sure you get the water out. Then re-lube the bearings and oil the coms.
 

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Discussion Starter · #19 ·
thanks for covering the motor-break in process.

Anyways!

Some updates over the past few days, everything has been
on hold since i dont have a gearbox for the sniper but now
finally i've managed to get my hands on another fresh MODIFY
Torus 8mm box and hopefully this one is A-OK!

i allso decided i needed a new cylinder-setup since the one i have
is incredibly worn out! (over 5 years old)

so i decided to go with the Modify Bore-up kit from WGCshop
and hopefully that will stabilize my fps a bit!

part from that i updated the look of the rifle, i reduced the length
since i've cut the barrel down to 510mm! buildt a new supressor out
of aluminum tubing and the endcap from the old supressor, some
spacers on the outer barrel to make it fit snug! the carbon look might
be too much but to be honest.. i think it looks just right! lol

i allso"redesigned" the 3rd cell of my lipo with velcro and allso gave
the stock a blanket of velcro enabeling me to add just about
whatever i want to the stock, patches, cheekrest or why not just slap
a spare mag on there? anything is possible =)

soon i'll get the stuff back home and i can start taking some pictures
and start working on the damn thing!!















Any ideas? pointers? :cheers:
 

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You stole my idea! I was going to put the Major League Sniper patch on my stock this week!

But I like how you did a lot of the stock with the velcro. Looks good. Now i have to find tan velcro!

And where did you get the big piece of velcro?
 
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