VSR troubles...

[Kagedwolf]

So, managed to fix my damned, yet prized, VSR for a skirmish last Sunday, it worked fine for all of about... ooooohhh... 30 minutes, then it started slam firing, now the funny part is I took it apart and put it back together, it started working perfectly fine, then after about 10 or so shots it starts to slam fire again. Repeat that many a time...

Now before any of you say sears or piston, both are in very good nick, there is very little wear on the piston sear, it's a laylax pss10 one, it's had at max, about 600 rounds through it. The piston is in good nick too, very, very little wear.

Now, after some research, I checked the teflon rings that sit in the receiver, both are still there, in the right place and solidly in place so no chance of sliding about. The spring guide stopper is fully screwed in, again, laylax pss10.

When it does slam fire, the piston sear engages properly, so the thing clicks into place when pulling the bolt back, pushing it forwards takes ALOT of effort and causes a slam fire. Now I've checked everything and it all looks good... So I'm stumped as to what it could possibly be.

Any suggestion, oh knowledgeable ones of Zeroin?

If it helps I can take and upload pictures of any parts as required to get to the root of this. The gun itself works properly right now, but I'm not sure for how long, there is a metallic grinding/scoring/scratching noise when pushing the bolt back into the receiver right now, the pull and push are fairly easy. The spring installed is a new laylax 150SP, had about 100 rounds through it, so it's not bedded in. Was pushing out about 465 FPS at the last chrono. Rising with each shot as the spring bedded in.

[Orion1]

Re: VSR troubles...

What cylinder do you have?

[Kagedwolf]

Re: VSR troubles...

That would be the standard stock cylinder, no obvious marking on it at all, and it's also in very good nick. Always lubed, etc.

[Orion1]

Re: VSR troubles...

Hmm, I get the feeling that maybe its the piston. Are the sears compatible?

[Kagedwolf]

Re: VSR troubles...

Hmm, I get the feeling that maybe its the piston. Are the sears compatible?

Yup. Everything inside is Laylax, sears, piston, spring, spring guide, cylinder head, etc... It's a new thing after about 2 months of use, everything is relatively new with little to no wear.

[Twisted Fate]

Re: VSR troubles...

have you had the trigger mech apart to see if nothing is jumping out of place my l96 did that turned out a spring wasn't sitting right soe the trigger sear was only just catching in the mech and returning the bolt to its forward position was enough to jog it as if you was pulling the trigger

[Kagedwolf]

Re: VSR troubles...

have you had the trigger mech apart to see if nothing is jumping out of place my l96 did that turned out a spring wasn't sitting right soe the trigger sear was only just catching in the mech and returning the bolt to its forward position was enough to jog it as if you was pulling the trigger

I'll give the trigger box a good strip and look at tomorrow when I get home from uni. It may be that, I'll post results of that.

[Twisted Fate]

Re: VSR troubles...

either way if its not maybe a strip , clean and re grease may do it some good (Y)

[Kagedwolf]

Re: VSR troubles...

either way if its not maybe a strip , clean and re grease may do it some good (Y)

Already did that with everything else bar the trigger mech :P

[Twisted Fate]

Re: VSR troubles...

aha there lies the possible weak link lol you never no buddy stranger things have happened in airsoft may just need a tighten up

[dazz666]

Re: VSR troubles...

Sounds like you have checked the obvious.

The stiffness when pushing the bolt back into the receiver after cocking isn't unusual. In fact with new parts you will indeed find it hard to push the bolt back into the receiver however this should wear down, ensure the inside of the cylinder is sufficiently lubed, especially the piston o-ring.

That said you could have a worn piston just in one area and thus when rebuiling the rifle it works for a while until the worn area of the piston catch moves round again into alighnment with the sear and not catching. See link below from PDI site which is very useful to demonstrate how the pistons in 45 degree setups wear down quickly.

http://www.x-fire.org/vsr10/e.triggerproblem.html

Ensure your trigger pull is correct, the trigger sear should have plenty of trigger to sit on - use the eylet in the mech box to help determine correct position.

Here's one to also try which i had a problem with......... the spring which returns (keeps up) the trigger sear is too weak and buckiling under high pressure. Take apart the trigger mech and replace the vertical trigger sear spring with one which is stronger - try this and report back to us.

Good luck.
Daz

[Kagedwolf]

Re: VSR troubles...

Okay.. So, took the thing apart again and checked everything. I took some pictures which are below. The most wear on the piston is indicated and the little wear on the sears is shown too. It's still slam firing after x amount of shots (changes each time I rebuild it). Could it possibly be the wear on that but of piston which is causing it to slam fire? And if it is, why doesn't it stop and continue normal firing as the gun is re-cocked each time? The spring is strong enough to hold everything, it doesn't buckle (tested and confirmed).

[Beef]

Re: VSR troubles...

Sorry to be a noob but whats slam firing meen? I to have a VSR.

[Kagedwolf]

Re: VSR troubles...

Sorry to be a noob but whats slam firing meen? I to have a VSR.

It's when you pull the bolt back and when you push it back forward it slams back into the receiver without loading a bb and pulling the trigger does nothing.

[TheChef]

Re: VSR troubles...

Its not the wear that might be the problem, is the trigger sear straight along its long axis, i.e. not banana shaped as this is what causes most slam firing. even if it has bent slightly itll cause it not to engage properly.