GothicGhost Posted June 24, 2018 Share Posted June 24, 2018 Hi all. I need to downgrade the spring for just under 350 fps. What spring should I buy? Thanks for any help. Link to comment Share on other sites More sharing options...
MisterG Posted June 24, 2018 Share Posted June 24, 2018 You need to provide more info. Do you know what it currently has? Is it stock? Was it new from somwhere abroad, if so the website might tell you what spring it has. If not we'd just be guessing, but if I had to guess I'd say you probably need an M100. But if you have a highly optimised AK, it might already have an M100 in there, in which case M90 or M95. You could also short stroke it. Cheers G Link to comment Share on other sites More sharing options...
Supporters Sitting Duck Posted June 24, 2018 Supporters Share Posted June 24, 2018 Easiest option - correct AoE (the cylinder head will fall out no doubt) That should drop 10 to 15 fps Just that one thing should do it You could, remove the heavy 8mm alloy spacer inside the piston you need a m3 nylon nut & penny washer This will lose about 40fps I'd say as it will not compress the spring as much now (it is about same as short stroking 3 teeth off - but you don't lose volume) If it is a full size AK with a 455mm barrel you can't Short Stroke as you need max volume Could SS a 74 with a 250~275mm barrel but need new piston with more metal teeth on rack SS 1 tooth for a 400mm barrel SS 2 teeth for a 350mm barrel SS 3 teeth for a 300mm barrel you can take an extra tooth off at a push but those are examples I tend to go with on volume Don't worry too much if some most of this way over your head - just saying If you drop spacer, then you need to improve seals, the o-ring is so-so on piston head wrap ptfe around the cylinder head to seal better could maybe change nozzle if you wish but there are two AK nozzle lengths To be honest, the least amount of f*cking about - correct AoE leave most of it alone perhaps and should be near 350fps If you start improving seals you likely will hit 400fps then you need to remove alloy spacer as well as AoE I mean you should if you was going to do it correctly gets seals really good, drop the alloy spacer, AoE, regrease etc... Then pretty sure you should have a 350fps gun cycling more efficiently and not needing to compress the spring quite as much all for next to nothing Or buy say a m95/m100 spring but problem is some springs can come in a bit higher/lower than expected generally you want a m95/100 for a full AK 455mm barrel or maybe a sp85/90 if it is a Garder spring (don't ask me about springs with percentages - fuctifino is the answer there) Personally I'd work with what you got if you know it is 365fps and go from there plus it is cheaper - no ordering of bits if you got asay a 22mm x 3mm rubber washer to correct AoE Or get more involved with sorbo/silicone, ptfe, m3 nylon nut, new/stretch o-ring etc... Still cheapy options working with what you got already but that is just my take on stuff Link to comment Share on other sites More sharing options...
Supporters Rogerborg Posted June 25, 2018 Supporters Share Posted June 25, 2018 Er, lop a coil or two off the spring? No need to over-complicate things. Link to comment Share on other sites More sharing options...
Supporters Sitting Duck Posted June 25, 2018 Supporters Share Posted June 25, 2018 Lopping coils is a bit of guess work plus need to finish/straighten coil end a 20~22mm x 3mm thick washer (not perfect like sorbo/silicone) that will reduce stroke by 3mm aprox = about 13fps like short stroking 1 tooth Correcting AoE & dropping 13fps - a washer & some superglue clean up cylinder head (washing up liquid to degrease) check old existing washer on stock head, if in doubt remove and clean up bit of cheapy poundland superglue... Plop plop refit old & new washer adding 3mm to correct AoE (or two washers if old washer ripped apart on removal) slap it back together - couple of minutes no hacksaw/pliers/molegrips/vice/file required Personally I'd be tempted to redo seals drop spacer but I'm a tart I guess but reckon cheapy simple no frills or extra messing with other stuff just correct AoE should do it about right - quick, easy & very cheap without too much work or guessing stuff Obviously if get seals really great then gun will likely shoot 390fps and have to remove spacer nah pull it apart carefully just correct AoE - ya gun's std piston will thank you for it in the long run Link to comment Share on other sites More sharing options...
Supporters Rogerborg Posted June 26, 2018 Supporters Share Posted June 26, 2018 21 hours ago, Sitting Duck said: Lopping coils is a bit of guess work I'd guess 2 coils. I'm pretty awesome, I just chopped my sniper down from an insane-in-the-membrane 600 to spot on 495 with one mighty cleave. 21 hours ago, Sitting Duck said: plus need to finish/straighten coil end 10 seconds on a gas hob. Link to comment Share on other sites More sharing options...
Huxley Posted June 27, 2018 Share Posted June 27, 2018 On 24/06/2018 at 12:37, MisterG said: You could also short stroke it. I tried that once, it didn't go well...... Link to comment Share on other sites More sharing options...
Supporters Druid799 Posted June 27, 2018 Supporters Share Posted June 27, 2018 2 hours ago, Huxley said: I tried that once, it didn't go well...... Did you buy it dinner first ? If not there’s your problem ! 😉 Link to comment Share on other sites More sharing options...
GothicGhost Posted July 1, 2018 Author Share Posted July 1, 2018 Thank you for the advice I will do the correct AOE first and see. And I need to buy myself a chronograph at some point. Link to comment Share on other sites More sharing options...
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