I get more range with hop up off? No hop/jams/less fps

[MikeRarrmeh [64oz]]

I have a KWA SR5. I have upgraded the barrel to 363mm 6.03 barrel(Madbull V2)(which is 138mm longer than stock, stock barrel is actually 225mm not 263), Systema duracon piston head, and prometheus air nozzle.

I'm pretty sure its started with the air nozzle, I switched it out because it has an o ring and the kwa one wasn't holding its compression when I tested it.

When I was playing at my field yesterday I noticed I wasn't shooting as fast as my friends stock devgru which was strange to me, so when I got home I opened up my GB and tested the compression (Piston-->Cylinder-->Tappet+air nozzle-->finger) and it's a perfect seal. I looked at my hop up rubber and its fine, no tears.

When I have hopup off it shoots totally fine, and shoots the speed it should. When I turn it from mid-->forward twice, so half rotation, the fps goes down visibly, and theres barely hop if at all, and range actually goes down. I turn hop up more, range goes down, and soon jams up and kind spits them out.

I put the nozzles side by side so I could see if they were the same size, and to me it look right. But maybe its a size difference not highly visible or even its thickness? So I'm thinking that maybe the air nozzle might be longer than the KWA one, and its sending the bb too far up in the hopup. Either that or possibly the air nozzle isnt as thick and its blowing more of the to the top/bottom of the bb, screwing with it hoping? I'm just guessing at this point, help would be awesome

[Paladin101]

I would suggest having a professional put the stock components back in the gun and fix whatever you did to the hop up unit.

[Burke]

Dumb question but is your nub aligned? If you look down the center of the barrel and add hop is the nub/bucking protruding into the barrel centered?

[MikeRarrmeh [64oz]]

I would suggest having a professional put the stock components back in the gun and fix whatever you did to the hop up unit.

I didn't do anything to the hop up unit, and I know how to work on GBs, been doing it for a long time now. I could easily put the stock parts back in, all the parts are fine besides the nozzle (it leaks due to no O Ring). I just wanted a ported piston head for ROF+ and less gear stress/no barrel suck. The barrel size matches the cylinder port for the correct amount of air. Its most likely the alignment of the air nozzle w/ the hopup, even though they looked like the same size to me.

[MikeRarrmeh [64oz]]

Dumb question but is your nub aligned? If you look down the center of the barrel and add hop is the nub/bucking protruding into the barrel centered?

Yeah it is, its the 2g bucking so its actually has arms in a V form, but yeah its there

[Burke]

Ive had similar isses with an m14 and the nub wasnt centered.....

You said you put the nozzles togther and theyre same size, I assume that means length and width as well?

[LiberalPacifist]

What weight bbs are you using and how hot is the gun? If you are using bbs that are too heavy for your bucking/spring, or applying too much hop it will jam or spit them out.

Also, how old is your hop up bucking? If its new it may not be broken in yet, and if its too old it may be worn out.

I have this problem periodically with my CETME, but its almost always because I tuned it incorrectly, coupled with the .25s and relatively weak gearbox spring I run with it. One of the guys on Fragistan got a RealSword SVD and couldn't figure out why when it was stock it wouldn't hop the .40s he was using, until we tried .25s. Then it ran great.

[MikeRarrmeh [64oz]]

Ive had similar isses with an m14 and the nub wasnt centered.....

You said you put the nozzles togther and theyre same size, I assume that means length and width as well?

Yeah they're the same from what I saw, I guess next time I open it up ill take them and measure the dimensions exactly just to be 100% sure. I just did a test with my upper receiver off w/ the barrel out. Made the gun shoot to where the nozzle was all the way forward, then but my barrel+hopup on the nozzle seeing if there was any resistance going back and forth, but there wasn't. I'll probably fiddle around looking at the bottom part of the 2 piece hopup and see if maybe the nozzle sits higher than the KWA one? Either way, even without hopup on when it shoots just fine, its still shooting at least 125-150 feet without dropping, so I can still play and make it work until I figure this crap out

[MikeRarrmeh [64oz]]

What weight bbs are you using and how hot is the gun? If you are using bbs that are too heavy for your bucking/spring, or applying too much hop it will jam or spit them out.

Also, how old is your hop up bucking? If its new it may not be broken in yet, and if its too old it may be worn out.

I have this problem periodically with my CETME, but its almost always because I tuned it incorrectly, coupled with the .25s and relatively weak gearbox spring I run with it. One of the guys on Fragistan got a RealSword SVD and couldn't figure out why when it was stock it wouldn't hop the .40s he was using, until we tried .25s. Then it ran great.

I always use .25s in my gun, its shooting 370 with .2, 335 with .25, i've always been able to use .25s in my gun, tested a while back and I could even use .32 with hop all the way up

Anyways my bucking is preeeettty old, id say about a little less than a year but i've shot probably 150k rounds through it

As for applying hop, when I use none it shoots strait 125-150 and drops at the speed it should be shooting, when I apply hop, it gradually decreases range and goes visibly slower velocity.

I have another 2g bucking and hopup, ill see if theres any difference tomorrow