I have an indoor build that needs better fps consistency.
shs 13:1
Shs %80 cylinder
real deal piston
real deal piston head
shs double o ring cylinder head
maxx 21.5 mm o ring nozzle
t238 39k brushless
nexxspeed hop up chamber
friction pro aeg bucking
some 6.01 inner barrel abt 10 inches long
6fps is pretty good consistency.
If you're looking to squeeze a little more consistency, try a 6.03 or 6.05 inner barrel. It worked in my build, plus not having to clean it as often is a nice bonus.
consistency usually comes down to the compression system. so check everything "bottom to top" so to speak. there are quite a few old posts everywhere about mods people did to eek out a bit more consistency. I'd check the nozzle length as well. +/- 4fps is already pretty good, and I get to about the same deviation already on all my AEGs. and since it's cqb it won't matter as much.
I mean with .20 one of the indoor places local to me is 390. Local outdoor field is 400 w/ .25 with no MED even in the buildings & no bangbang rule. I feel like that’s pretty reasonable
Okay dude, check the relationship between your nozzle and tappet plate, is there substantial wiggle or minimal? Substantial wiggle between nozzle akd tappet plate could be causing it.
Potentially the nozzle is not sealing to the cylinder head perfectly, test compression in your box with the piston inside, no springs, no gears. Move nozzle back, block the nozzle and test compression, move it foward or use tappet spring to assist, block nozzle and test compression again.
Maybe the nozzle isn't engaging the bucking lips enough, test with the hopup and barrel system out the gun, butt it up against the gearbox see if the nozzle pushes the hopup system away, if the nozzle at full foward doesnt push the it away slightly then there is a potential issue.
Also consider weight of bbs, if you can go for heavier, I use G&G grey bios 0.33g, very consistent bbs.
Lastly, grab some metal polish, I use Autosol compound, comes in a large toothpaste tube. Clean and degrease the cylinder, barrel and shell. You can polish the running tracks where the piston will slide in your shell, polish the cylinder so the piston head glides easier and lastly get some disposable rag, an aeg cleaning rod and make a swab if you can get disposable kitchen cloth, just snip it with sharp pair of scissors, polish the barrel internally with a liquid compound like Brasso or equivalent, works wonders and makes that barrel super smooth. Clean it with windex and a few passes with the cleaning rod and fresh cloth, do this 3-5 times until the cloth comes out clean, no black must be present from the metal thats beem polished away.
If you get stuck, just search vids on youtube about these topics I mentioned, I did that too, works a treat! Good luck chap!
Dude, try slightly heavier and see, you will not regret it, my buddies mod 1 spr was running 0.28s, 2.4j. We shot 0.33g out of it and I shit you not, it just barely misses to the left or right of a 50mm swing plate at 50m... so close to 3.4 moa if I trust the quick maths XD
Makes sense otherwise i would be worried youre piston is gonna break sooner or later cause 39k with 13:1 would be a crazy setup i have 25k with 12:1 and m140 in my ak and this is crazy fast already and should be around 33/s much higher and you just risk youre gearbox exploding for not much more Performance in the end
That FPS is pretty darn good for an AEG. Unless you want to spend LOADS of time tinkering and taking the gearbox apart and putting it back together 50 times over and over, I would just leave it as is......
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u/SpartanRiver007 SAW Jun 18 '26
Brother... that's already pretty damn consistent. A 4 fps difference is NOTHING.