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 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 70D bucking
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:
VFC 8mm bushings
Siegetek 10.44:1 gears
ASG 28tpa motor
VFC bearing spring guide
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 50d bucking
Prometheus 6.03 x 407mm barrel
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.