VFC Sig Sauer M17

[Lluis]

Hi,

Just recently got a sig m17 used in very good condition. Being aware that this stem has a lot of issues however it was shooting fine first few mags when they were nice and warm and then now it shoots every other shot. Skirmished it all day yesterday and this just happened constantly. I am running 0.3g bbs I have tried 0.2g green, red and black gas and I can't get it to shoot consistently. Now I'm back home and the mags are warmed up all fine other than the odd shot. Anyone who has owned an M17 have you ever got it to run consistently or have I just buried myself into a no fix hole... Cheers

 

[Chev Chelios]

Can you take the slide off and take me a well lit photo from the top with the magazine in with a cocked and non cocked hammer please (want to see the valve knocker)

Do you have a valve key? If so can you screw the valve into the mag loose (hand tight then back off just slightly) and see how that affects the issue. 

When the issue starts try pushing and holding the mag in the gun (want to see if the nozzle to mag seal is playing up) 

Again when the issue starts if you can shoot it upside down and let me know if any change.

Just trying to diagnose what might be the issue, if you can be arsed a video of the gun firing when playing up would be a big help.  

Edit: Also does the fake outer barrel move in and out of battery with the slide when you fire it? If possible assemble with out the outer barrel and give it a pop.  

 

[Lluis]

Can you take the slide off and take me a well lit photo from the top with the magazine in with a cocked and non cocked hammer please (want to see the valve knocker)

Do you have a valve key? If so can you screw the valve into the mag loose (hand tight then back off just slightly) and see how that affects the issue. 

When the issue starts try pushing and holding the mag in the gun (want to see if the nozzle to mag seal is playing up) 

Again when the issue starts if you can shoot it upside down and let me know if any change.

Just trying to diagnose what might be the issue, if you can be arsed a video of the gun firing when playing up would be a big help.  

Edit: Also does the fake outer barrel move in and out of battery with the slide when you fire it? If possible assemble with out the outer barrel and give it a pop.  

Hi mate, just gave it a deep clean and re greased and oiled everything up. No change still misses every other shot.
 

Two older mags I have changed some of the o rings on as they were leaking anyway. The mags sit tight when inserted and there is no play up and down, even when trying to push them up when firing no difference.

Upside down it will fire correctly for some reason so I suppose that means it needs more gas to come out? I have got a stronger amg hammer spring to see if that helps.

I notice it gets stuck a little bit if I gently cock it back, it sounds almost like there is some part rubbing. I am just not able to see what it is. When i take it appart after firing the liquid left inside has some black residue so some black part obviously. I have heard of people filing back a part just not sure what.

I have attached an image showing how it got stuck.

View attachment 111946

 

[Madhouse]

My P226 was a bit like that when new, was sluggish to return and as a result wouldn't fire consistently - by sluggish it didn't have the energy to lift a BB from the mag's feed lips. Hence when I chrono'd it I got readings between 0.5j and 16.6j (1336fps on a 0.2!! - not sure what happened there).

Not sure I'd call it a fix but a clean & lube and then manually cycling it certainly freed it up, followed that with a few mags using maintenance gas and it's cycling nicely now at 0.7j / 277fps on a 0.2 using 144a.

Actually, looking at your picture, you've not even got the mag in. When you had the slide off was the piston moving freely and returning nicely?

(apologies in advance for any dodgy terminology, I'm still learning about gas guns myself)

 

[Chev Chelios]

Upside down it will fire correctly for some reason so I suppose that means it needs more gas to come out? I have got a stronger amg hammer spring to see if that helps.

Ahh good stuff. 99% sure its the barrel binding (why its cycling fine upside down) if you don't want to go down the filing route, they sell new outer barrels to stop it happening when a suppresser or comp is fitted but should solve the issue you are having. Have a search for "non tilting vfc sig sauer m17 barrel". 

Vid showing what I mean if my gibberish does not make any sence https://www.youtube.com/watch?v=MkoSYWSA_bs&ab_channel=GunSightTV

 

[Lluis]

Ahh good stuff. 99% sure its the barrel binding (why its cycling fine upside down) if you don't want to go down the filing route, they sell new outer barrels to stop it happening when a suppresser or comp is fitted but should solve the issue you are having. Have a search for "non tilting vfc sig sauer m17 barrel". 

Vid showing what I mean if my gibberish does not make any sence https://www.youtube.com/watch?v=MkoSYWSA_bs&ab_channel=GunSightTV

Thanks for the quick replies and info! Got it fixed for now by filing down a strip of metal on the slide nozzle housing which would rub on the hammer wheel. It was missing a spring for the Gas Cutte as it was second hand so added a new one and no full auto issues. At the moment I got no more problems so wont be touching it lol but I'll keep the barrel thing in mind. Thanks a lot!