changing the spring on a hk417?

[chris_taylor]

hey everyone, recently bought a vfc hk417 and chrono'd it last night to my dismay 358-362 fps. but the sights i play at are 330. does anyone no how to change the spring on it? google is no hope and i undone every screw i could physically see and i could get the gearbox out. :S

any help will be greatly appreciated

[Razielkah]

Re: changing the spring on a hk417?

Out of curiousity, is the rifle brand new? If so, you will find a drop in the FPS after a few magazines have been put through it. So if you can try wearing it in at home by putting 3/4 mags through it and see if you notice any difference.

Failing that, it appears to have the standard v2 gearbox (There a pain in the ass) Once youve undone all the screws in the upper and lower reciever, removed the stock tube etc, there should be a pin you need to push out above the trigger, have you done this also? That pin goes straight through the center of the GB and holds it firmly in place!

Goodluck

[chris_taylor]

Re: changing the spring on a hk417?

yes it is, but on the note of v2 gearboxes i have had m4's before and it isn't fixed by the stock tube, its a 3 part v2 .2?? its odd but there appears to be no pin either near the trigger.

[badger906]

Re: changing the spring on a hk417?

leave the gun half cycled over night, will bring the fps down a bit.
And is that chronoed with no hop? Applying hop lowers the FPS, unwind the hop fully on my M4 and it shoots at 343fps (legal at my local) but if i have the hop set to where it fires straight and far, it shoots at 315-325fps

[Mace]

Post this on the AI page as they took one apart for their review a couple of issues ago (vol 8, issue 4). I seem to remember they said that all but the front body pins were dummies. You do need to remove the buffer tube and then remove a plate which masks a bolt and this with the bolts on the grip retain the gearbox. Not sure if there were any other things to note. They too found it shot hot and suggested an M100 spring or trim a coil from the existing spring. I've not got mine chrono'ed yet but I'm going to bump mine to 400 or so with a stiffer spring and use it as a DMR so not worried if it's hot out of the box.


Sent from my iPhone using Tapatalk

[chris_taylor]

Re: changing the spring on a hk417?

no, thats with the hop set and hits 360fps. i will try the half cycled thing but i think its a spring change jobby

[chris_taylor]

Re: changing the spring on a hk417?

ahh, thats cool. how are you locking it to semi? mosfet?

[Mace]

Re: changing the spring on a hk417?

At the moment i'm thinking about a plug and play unit like the Burst Wizard. I don't think it would be easy to hard wire given the particulars of the gearbox (AI comments not mine).

[chris_taylor]

Re: changing the spring on a hk417?

yeah, thats cool