Austeyr

Changed the bucking over to the original black one, still having FPS spikes albeit a LOT hotter, one of the shots chrono'd at 468 (On a .28g BB 😳) The hop unit is bolted to the back of the barrel so sits firmly against the gearbox, and has a large spring also pushing it against the gearbox too. I noticed the hop unit itself has some wobble on the top wheel which seems to be a common thing with these, so I'm going to try the mod shown here;

Thanks, I’ll give that a try!

Took my Cyma SVD out Sunday and noticed every now and then my shots would veer off randomly. Today I figured I’d chrono it and the variations are all over the place. All readings are on a 0.28g BB 313.4 386.6 392.1 317.6 312.6 318.8 316.0 315.7 318.1 386.1 319.4 319.3 323.3 322.6 299.8 317.5 324.3 304.1 320.2 325.8 324.6 304.0 400.2 I fitted the following parts: FPS Airsoft Aluminium Cylinder Head for CYMA SVD FPS Airsoft Ergal Air Nozzle Inner O-Ring for CYMA Dragunov SVD CYMA SVD/SVU Piston and Head Set ASG Ultimate Mil-Spec AEG Spring (M135) Maple Leaf MR Yellow + Omega Nub When fitting the cylinder head I had to remove a tiny tiny part of the oring edge to get it to go into the cylinder, but the air seal passed all of the tests… What could be causing the low fps (In terms of the spring power) and the random jumps in power? I’m thinking of buying the Cyma cylinder head and nozzle but the cylinder head has a 21 day wait time

What kind of rifle are you using? It would help to help give a better answer. Personally I use an Acog/Elcan which only really aids in target acquisition like Tackle mentioned. That being said, using an LPVO with a true x1 is the best of both worlds and you can pick them up for a relatively cheap price!