Danerd's Various Builds and Tech Thread

So, starting off with the SR16:

I originally built this thing as an HPA setup with a Protech Mk2.5. Now, there wasn't anything wrong with it, and it actually performed pretty well. I was offered a Gen3 V2 Fusion Engine in exchange for it, and I couldn't say no. After installing the FE and getting it dialed in, I quickly realized this:

HPA (in my opinion) takes a good amount of fun out of the sport for me. It was stupid easy to get dialed in and shooting like a dream. My qualms with it were these:
- It took the satisfaction out of building a gun that performs extremely well. In my case, really getting to know what makes your gun tick. Simply dropping something in with little (or no) major tuning and boom, instant high-end performance is a detractor for me.
- The dang line and tank. These took up valuable space on my kit and I just wasn't a fan. Now, I know what some of you may be thinking "Well, you just have to get used to it". Ive been playing with AEGs for 11 years. I remember when Polarstars first hit the market. I wasn't a big fan of them then or now.
- I don't have good access to a source of air. Surfing and scuba shops aren't really a thing in Northeast Ohio (while they do exist, they aren't widespread), and the closest field for me that does do fills is an hour a half drive over in Pennsylvania. With the amount of shooting and tuning I do, this was the biggest factor in me ditching HPA.

Soooo..... I rebuilt it as an AEG. Digging through the bag of parts I pulled out of it, I took stock of what I had, and what I wanted the rifle to do. I wanted a platform that would get great trigger response, be highly accurate, and have a respectable rate of fire. Now I did a build back in 2013 with a G&P VLTOR Mk18 as a base, and it shot amazingly. 399-401fps, 39rps and dead-on accurate out to 220ft. The parts in it were:

G&P Shell
G&P 8mm bearings
G&P Tappet plate
ZCI Bearing spring guide
Seigetek 10.44:1 Gears
SHS High Torque motor (16tpa_
SHS M130 Spring
SHS 15t piston
SHS Nylon piston head
ZCI Anti-heat cylinder
G&P Cylinder head
G&P Aluminum o-ring nozzle
BTC Chimera Fet
Lonex hopup
Lonex 70D bucking
IR-Hop
ZCI 6.02x320mm barrel


I based the SR16 build on that G&P. As the old saying goes, "If it aint broke, don't fix it", but I did make a few improvements on the second go-around. After selling the Fusion Engine, I needed a gearbox for this thing. I opted for a Lonex, as I have had good experiences with them in the past. The only issue with the Lonex shell is that the back end is a tad thicker than the VFC shell and needed some dremeling to get it to seat right.

I also opted to get rid of the Lonex bearings and replaced them with the steel bushings I kept from the VFC shell. I've blown bearings from Lonex, G&P, and even Modify Ceramics. For me, I prefer ultimate reliability over the slight performance boost bearings can offer; those being less resistance and an ever so slight rate of fire boost. A few other parts were changed for better ones, those being the spring (A Guarder SP110 instead of an SHS), the barrel (A Prometheus instead of a ZCI) and I changed the motor from a 16tpa to an ASG 28tpa. Ive been using buffertube lipos to power this thing, and as a necessity to not overdraw them, I needed a motor that I knew had a good track record of being efficient and would give me the performance I wanted. The updated build list is:

Lonex Shell
Lonex Tappet
VFC 8mm bushings
Siegetek 10.44:1 gears
ASG 28tpa motor
VFC bearing spring guide
Guarder SP110
SHS 15t piston
SHS Aluminum piston head w/ bearings
VFC full cylinder
VFC o-ring air nozzle
ZCI aluminum cylinder head
BTC Chimera fet
Lonex hopup
Lonex 50d bucking
Prometheus 6.03 x 407mm barrel
IR hop.

It averages 335-338fps on .28s which translates to 1.46 - 1.48J, and 26rps on a fully charged lipo. With a 10ms precock, the trigger is lovely, any higher and it begins to double cycle. Accuracy wise, its darn near a tack driver with .28s. Buuuuuut, being the person I am, it could be faster Dont get me wrong, 26 is very respectable, but it could be better. I've worked some numbers on various motor setups when paired with the 10:1 gears, and Ive settles on a 22tpa to get me where I want to be. With a 22tpa motor, I should be getting around 34 rps and still retain a decent amount of efficiency.

I went ahead and built myself a 22tpa motor. Now you may be asking why I built one instead of buying one. Well, I have a few neodymium cans laying around and a pile of older motors sitting around begging to be ripped apart . Besides, motors are a tad pricey at the moment and I have a few build to work on that are going to need some funds put into them. It took some trial and error to get it right, but the motor turned out pretty good.

- Krytac can
- VFC armature (oddly enough)
- SHS Neo magnets
- JG endbell
- G&P motor bearings
- ACM pinion (that is getting eaten alive by the Seigeteks...it just doesnt seem to mesh well)
- SHS tower.
- 2mm bullet connector mod. Because spade connectors break easy and suck.
It gets me 34.4 rps on an 11.1v lipo. Not too shabby at all. There is just one teeny tiny issue....
It cycles fine without a mag; it sounds smooth and clean. However, with a mag, it makes a horrendous grinding noise, but shoots perfectly fine. In my experience, there is only one thing that makes that noise.............PME. Why it hits PME only when a mag is in it is pretty confusing. Pulling it apart to check shows definitive wear on teeth 3, 5 and 8 on the piston, whereas the rest of the teeth are fine, so it is hitting PME. The only thing I can think of that is causing that is the backpressure from a chambered BB creating a bit of an "airbrake", slowing the piston down just enough for it to hit PME.

Ive since ordered a few M120 and M130 springs to toy around with and a few new pinion gears to replace the one that is getting eaten up, as well as for a few future builds I will be installing the beefier spring this evening and will update later.

So, a few new developments:
- installing the M120 and removing the bearings on the piston head have yielded the same results as the Guarder SP110 with PH bearings. The PME issue is now gone!
- Frank at BTC will never hear the end of me... I have a few items that are in need of repairs, and once that happens, another build can start.
- the motor turns into a pretty nice handwarmer rather quickly. This was to be expected given my setup, but it shouldn't be heating up as fast as it is.

The SR16 currently chronos as follows on G&G non-bio 0.28s:

337.5
336.2
335.7
336.2
336.3
338.6 * (highest)
337.8
336.7
336.1
335.6
336.2
337.0
334.8 * (lowest)
335.6
335.3
337.5
336.8
336.7
336.9
336.7

AVG: 336.51
MAX DEV: 3.8

So not too shabby at all. Chrono readings on BLS 0.32g rounds give around 300fps. The range and consistency on the .32's is equal if not better than on the .28s, despite the lower fps and joules behind each round. My end goal is to have it shooting as close to 1.5J on .32's as I can, which if my math is correct, equates to 317 fps. I did do some earlier calculations that if I were to add the bearings back onto the piston head, they give about a 20fps boost. That would be nearly dead-on to where I want it. Accounting for the eventual break-in of the spring, it should be a tad under that 1.5J threshold and be reasonably within fields' requirements near me; and not shooting crazy hot or packing too much of a punch.

Will update later.

USPS was generous today. Among the goodies were a Gate Titan and a new hop up for the M14. Some of you may be thinking, "wait a second, didn't he have a BTC fet in that SR16?", and you would be right. I sold it off and used the profit from that to pick up the Titan. So why the switch? Its not that the BTC fet was bad, in fact I've been lovingly using them for years, and have hoarded those that I have picked up. The fact of the matter is, BTC has been pretty slow to respond to customer inquiries for repair services and is lacking in aftermarket customer support. I've installed Titans in a few customer guns and have liked some of the features they have on them; and lets be honest, they are much easier to obtain, and Gate generally has better support as of late...

Anywho, after installing and getting the Titan setup, I realized something... All of my (high-power) batteries are wired for XT60 plugs, and the Titan is wired for Deans. The dilemma is this: I can rewire the Titan to XT60, and void the warranty, OR, I rewire all six of my batteries. I have to rewire the Titan from the usual spade connectors to 2mm bullet plugs, so I'll be voiding the warranty anyway. I think to make life easier I'll just wire it up to XT60, and make a Deans-XT60 adapter so that I can still program the unit. I also re-installed the bearings onto the piston head. Hopefully the extra compression will give me the joule readings I want. Will test things in the morning and post results.

Once this little project is done, I think I may start on the G36. So far, it looks like the next project that *shouldn't* take too much time. But seeing as how this is airsoft, I doubt that will be the case.

UPDATE:
The SR16 is being finicky. It seems that the selector isn't engaging the sensors quite right, and is leading to misfires and dud trigger pulls. Looks like I have some tuning to do to the Titan. I did manage to get a few sets of test data. Those are below:
EDIT: It was the selector sensors misbehaving. Issue has been fixed.

BLS 0.20g (ZCI M120, Bearing Spring guide + Piston head) Hopup OFF:

401.6
400.2
400.7
399.2
401.2
398.5 *
400.3
401.9
400.7
399.8
399.4
400.2
402.4
399.8
402.3 *
400.6
400.8
399.8
399.2
400.6

AVG: 400.46 fps
DEV: 3.8
Joules: 1.489

Now, here is where things get interesting:

BLS 0.32 (ZCI M120, Bearing spring guide + Piston head) Hopup OFF:

320.0 *
323.7
321.4
322.9
322.7
322.8
321.3
322.3
323.8 *
323.4
323.4
322.0
322.6
322.0
322.6
322.6
322.6
321.8
323.8
321.6

AVG: 322.465 fps
DEV: 3.8
Joules: 1.545J

The 0.20g energy output is 1.49J, compared to the 032g 1.55; thats a 0.06J increase. While that may not sound like much, it actually matters quite a lot. That can be the difference between playing at a field or not. Luckily, my local fields' limit is 1.56J w/ .30g, and doing the math, I should still be under (but only by a hair). With .32g rounds and the hopup ON, results are also interesting. It chronos in at 309-312 fps, with the joules coming in at 1.45. The reduction in energy directly equates to the loss of velocity, yet it is shooting just a tad under what the .20g rounds do, despite these being 55% heavier. So, why does it do this? Im fairly certain it is the result of a phenomenon called Joule Creep. I won't go into the nitty gritty specifics of how it works, but I know why it is happening in my setup.

My cylinder to barrel volume ratio is more than what is needed to propel the bb down and out of the barrel. The excess volume ends up putting more energy behind the bb for a longer period of time. This effect is not seen with the .20g rounds because they are too light. However, the heavier rounds have more mass, and thus require more energy to move them. The excess air behind each round is what gives the bbs that extra energy, combined with the additional mass, and you get a round that has the same (or similar) energy behind it as a much lighter one. The perks to this:
- better range (when combined with a properly tuned hop setup)
- better accuracy (generally speaking, but there are situations where too much extra air can cause rounds to fly off course)
The only big downside is that your rounds are not traveling as fast as lighter ones. This doesn't matter in CQB as the distances are too short to make a quantifiable difference. However, at range, it can make a difference as your shots will take a tad longer to travel their distance to target.

Ive posted a batch of results that the software has gathered from the Titan unit. Not bad at all if I do say so myself. My setup is:
Riot 10.1 gears
28 TPA motor
M120 Spring.

I may just re-tune the motor and speed things up a tad My batteries are 11.1v 2200mah, 30-60C and 40-50C discharge respectively. This setup is barely making them sweat.

Where do I even begin???

Things have been crazy the past while. Graduated college, job search, interviews, travel....
I have managed to secure a job, the caveat being that I am moving half way across the country for it. Its a brand new start in a new state. I'm looking forward to it, but getting all of the logistics in order has taken a the majority of my time. That being said, does anyone know of any good fields in the Springfield, Missouri area? There is a small shop that would be local to me (thank god. there isn't s**t on a stick in northeast Ohio) and a few places in and around the Joplin area...

Once I'm done moving and get settled in, things will resume. In the meantime, I have been busy picking up a few items One additional BTC Chimera, and a 2014 VFC HK416C

Crazy week. New job, new state....new....everything. Except these projects, those haven't changed

The 416 project is coming along, although I personally won't have it. It's going to someone else who wants it built, and wants me to do it while I still have it. For now, its just getting a basic overhaul until the customer figures out what they want done, if they want anything.

The M14 is on indefinite hold as of now; that is until I get a few more tools and make a space to work on it. I just don't have the room or facilities to continue on it.

The G36's (yes there are two of them, 1 C and 1 E) are in progress. I need to pick up new motor cages for them, and source a few external parts to get the E where I want it. I also need to send the Chimeras I have back to BTC for repair, so this project will continue when I get those sent out in the morning and they are repaired and come back. Hopefully that doesn't take too long, but we'll see.

There is a new addition coming in tomorrow (at least that's what USPS is telling me. Hopefully the package isn't swiped while I'm at work): another VFC SR16. Its identical to the tan one I have, but its black, not tan. This one will be my 'new' primary while the tan one takes a backseat. For this SR16, Im going to build it extremely similar to the tan one. Speed gears, torque motor etc... A very well-balanced field rifle, great range, accuracy and trigger response. However with this one I want to test a theory I have. With my choice of external furniture, I will be limited to buffertube lipos, so efficiency of the system is paramount. There are plenty of topics all over about what setup gives the best response, short of building a DSG; whether those are combinations of torque motors and speed gears, or speed motors and torque gears. The most accepted setup is a combination of speed gears (10,12,and 13:1 ratios) and typically 16,22, and 28 tpa motors. My theory is this:

Lower ratio gears are less likely to pull heavier springs due to their lack of torque. This is simple mechanics. To compensate for this, stronger motors are used that are able to pull said springs. This typically comes at a cost of the motor having to pull more amps from the battery. Higher tpa motors are able to generate stronger magnetic fields with fewer amps, thus they are more efficient. Add in stronger neodymium magnets, and the efficiency increases more. The principles are similar in a setup with a speed motor and torque gears, except the motor is used to keep the system's cyclic speed from being too slow. The gears in this setup are capable of pulling the spring; the motor in this case primarily moves the system. If a balanced setup were to be used, how would this affect the performance of the system?

For example, lets assume a typical setup:
13:1 gears
22 tpa motor
M120 (for a 400 fps field rifle)

If we look at the ratio of the gears, to the tpa of the motor, we find it comes out to about 1.692:1, meaning the motor has to work almost 1.7x as hard as the gears to move the load. Add in the resistance characteristics of the system (spring, piston, tappet, gears, etc..) this can easily approach a factor of 2:1 if not more. If the motor pulls 10 amps with no load, and 17 amps under load, this means the motor needs at least 17 amps to perform properly. Here are a few more ratios:

10:1 gears
28 tpa motor
M110
Ratio: 2.8:1
*This is the current setup in my SR16

12:1 gears
22 tpa motor
M120
Ratio: 1.83:1

When the motor needs to draw additional amps, the effect is additional heat. Heat is a killer of any electrical component, and sometimes it doesn't take much to do permanent damage. The plan I have for this SR16 is a balanced build. I'll be pairing 16:1 gears with a 16tpa motor; in theory giving a nominal gear-motor ratio of 1:1. This *should* spread the systems' workload evenly, reducing the total load on the motor, and increasing the efficiency of the system. The overall idea to build a platform that maximizes performance and battery longevity, without overdrawing the power supply (because lipo fires are NOT fun).

Obviously this is just an idea. What do you guys think? Does any of this make sense, or am I spewing total crap?

The 416 is done as of now. The customer just wanted some basic tuning. That is set to go out next week. In exchange for the 416, hes sending a few internal components, a UBR stock, mags, and a Dboys SCAR H. Looks like another project. Ive been tossing around the idea of building a .308 short-barreld battle rifle for some time. This may be a good opprotunity to try that out.

The other SR16 arrived Thursday. Sadly, its not the Asian version (the one with all of the laser engraved trademarks on the rail and in other places.) but it still has the deep engraved trademarks on the body. Its in pretty good shape for being an older VFC model. It has some leftover residue from a few stickers, but its nothing a bit of rubbing alcohol wont get rid of. The parts for it from Brill also arrived Thursday. If there is one thing I hate about the older VFCs, its that they dont like SHS pistons. It took a while to grind down the piston rails and polish them up to where the piston slides freely.

I also paid a visit to my local Army surplus shop. They have some really great items in there, including an original Colt 1911 circa 1913, and a few World War 1 US Infantry rifles and a British Enfield. They also had a few packages of authentic Knights Armament rail covers and foregrips. Ive been looking around for a set of rail covers in general and have yet to find anything that I liked... untill today. The nice thing is that all of the serial numbers on the packaging, covers and grip all match; so its not just a random set someone may have thrown together. I'll work on getting pic of the stuff in the morning.

Pics of the goodies are up. Also, thats a nice looking gearbox for the SR16:
- VFC shell
- VFC 8mm bushings
- SHS 16:1 gears
- SHS 15t piston
- Guarder tappet
- Guarder SP120
- VFC aluminum piston head
- VFC full cylinder
- VFC spring guide
- G&P aluminum cylinder head
- 1/8" sorbo + 3/16 neoprene pad
- VFC oring nozzle
- BTC Chimera
- Retro Arms straight trigger

@BOA_SP3CT3R I know the exact ratio wont be 1:1, but for the sake of easy math, its close enough I have pulled "16:1" ratios out of a few VFCs before as well.

The SR16 is finally back together after giving me quite the headache. The larger wiring I put in it was causing some fitment issues, as well as for whatever reason the Umbrella Armory grip I wanted to use seemed as if it was throwing off my bevel-pinion alignment. I put the VFC A2 grip back on for now until I figure out the exact cause, as it works perfectly. Overall, the gun cycles extremely smooth, and actually double cylces on semi auto with an 11.1v stick. No big deal, nothing a fiddling with the settings on the Chimera wont fix.

I also dug through a box and found my old KJW Hi-Cappa. I got it in a trade years ago and it bit the dust some months ago before my move. The disconnect went and it turned into a cannon. I spent some time this evening rebuilding it, installed a ZCI steel disconnect, and now it seems to work great. The Tanio Koba grips on it cause the TM mag to not seat correctly if the baseplate is attached. I'll have to dremel it down a tad so the mag seats with it on. In the future I'd like to put a PDI W-hold and ML Crazy Jet in it. Ive had really good experience with that combo in the past; or I'll just Rhop it

While I wait for BTC to get the Chimeras I sent in for repair, I think I'll start on the G36. I have the vast majority of the parts I want for it, save for a good barrel and the external pieces. Im thinking of just 18:1s and a 14-16tpa motor. Just something that will be a good workhorse. With it being the full-size G36, the chance to turn it into an MG36 and have a more unique support weapon might be neat. The only real differences between the G36 and MG36 is the latter has a heavy match barrel, integrated bipod in the handguard, and typically uses the 100rd beta mag. Since this is airsoft, the barrel is irrelevant. The handguards and beta mags are relatively easy to find and would be a cheaper option than to pickup a comparable platform. Plus, the option to fill a dual-role, that of either a rifleman or SAW gunner could be nice.

The SCAR and other goodies arrived today. The SCAR is pretty plane-jane, other than the previous owner did mod it to take SR25 mags. I think this will be a great platform for an SBR battle rifle.

The UBR has needed some modding to fit. The buffer tube is a few inches too short to fit my lipos, wiring and Chimera. However it does have the compartment inside that makes a perfect little spot to tuck everything away in. 15 minutes with my dremel and its a pretty slick setup: All I have to do is pop the door open and the connections are all right there. Changing the battery is a bit more involved, but I'll get the hang of it. The rifle chronoed 427 fps on .20s +/- 1.8. Thats too hot for my fields, so I need to shortstroke. 2 teeth should put me around 390-400.

Potato pic of the stock: