Ak fps drop and rise?

[dazzer106]

Hi All
A while ago I brought an SRC AK47 TAC, took it along to my local site for its first skrimmish. So after lunch time break took over to have the chrono done to take a diff gun on, so fired a few shots though chrono and FPS came out a dissapointing 260/280 range ( hmmm I thought place I brought from advert said FPS 330) still took it on. So when I got home that evening and set about cleaning my two guns that that I used. All I did was clean barrel, mag well/ hop area then sprayed with silcone in mag well and down barrel. Left it for a week and went to local site again. Got to chrono gun to take on fired 1st rnd 390 fps 2nd 460 fps 3rd 490 fps 4th 420 fps. was told gun was to hot and what did I do to it all I said was clean it had a few raised eyebrows was told to fire a few full brusts though it, retired chrono but FPS was still in same ranges as before (lucky for me I took 2 guns with me). Now I havent got a clue what has happened here as all have done is to clean out barrel and magwell. I've only used this gun once now and had it for about 4 months, no internal mods have been done too it, all that has been changed is front rail. Was told by site that spring has to been changed (wouldn't have knowledge how to) but i dont want to pay out if it doesnt need doing

[Crude Skinny B]

Re: Ak fps drop and rise?

Well I would not advise spraying silicon in the barrel to start or hop up as they should be as clean and dry as possible. Having a barrel full of silicon will only rub off into the bbs causing advers effects on accuracy and fps.

My first theory would be that the silicon has dislodged any dirt inside of the barrel causing the fps to rise.
Another would be that the silicon almost acts as a seal between the walls of the barrel and the bb causing a "better" seal therefore increasing fps. Not sure if that would actually work but just an idea.
Perhaps originally the hop up was on too much and slowed the bb down significantly, adding silicon has made the hopup rubber more slippery.
Maybe the nozzle seal better with the added silicon in the hop up rubber.

A lot if ideas but I would thoughly clean the barrel and hop up once it has been removed from the gun.
Then re chrono.

The fps jumps around quite a bit to, meaning that there was/is some kind of air-leak within the gun: gearbox, hopup etc.