VSR-10/SD-700 (slam Fire)
 

I've read a lot of treads about this problem and now I'm having the problem.

What's the clear fix for this problem? New piston or trigger parts?

To to state the problem clearly:

The bolt will lock back but with a little pressure it will slam forward. I've taken the gun apart to try to fix it and remove a ton of grease. It worked for 60-100 BB's then it went back to slam firing.

I'll post a video later tonight.

Short term is the piston. Installing a Prometheus Red piston will solve the issue until the trigger sears break.

Basically, the weakest part fail first. If you replace that nylon part with an aluminum/steel part, then the next weakest part will break, in that case the sears.

Thing is that the RED piston does not work with aftermarket trigger units. You need either the Prometheus ORANGE piston or PDI VC/HD piston, both have the rear end made different, like an L96 instead.

Would the airsoft gi vsr parts work? Does anyone use those?

Yes, it would work, but no one uses it because they are a lot inferior quality for a not so good price.

No one that use a VSR-10 on a regular basis uses the RED piston with the stock trigger box. It breaks too often. Remember that the trigger was designed to break when past 330fps (japan laws), so what ever part/upgrade you want to install to improve it, it will fail again.

You can get the Prometheus trigger + piston for about 200$

Thank you Kos-Mos. Well I guess I'll put that on the Christmas list lol.

unless, you upgrade the trigger sear on the trigger box

I'm going to do a mod I seen on youtube for the trigger sear to see if it will work till I can get the real parts I need. It involes putting a screw in the sear.

No, that last until it breaks the trigger box. It is not the trigger sear that breaks, it is the second, the long one with all the other parts attached to it. It breaks where the joint to the first sear (the one that contacts the piston) is attached, right in the cross pin hole.

I have seen "upgraded" sears break 4 times in a single summer. It would have been more cost-effective to change the trigger completely.

Kos-mos..... that is the trigger sear bud. The one that hits the piston is the ... piston sear.

The piston sear likes to wear down, but like it was said first it will be your plastic piston, it will get a flat spot. Than when you go to a metal piston your stock pot metal piston sear will wear down and get a grounded edge. Than depends on spring strength your trigger sear will break. Pretty much right in the area you described.

The thing is even on the upgraded trigger sears right where the piston sear sits there doesn't seem to be alot of "meat" and its where all the pressure is.....

Well I've got the gun firing normal again.

I drilled a hole in the sear which stops the piston and put a screw into it to build it up. Then a grinded down till it would catch the piston. I know this will kill the plastic piston but I've ordered all new upgrade parts for that part of the gun (sears, piston, spring and spring guide).

That is exactly why we upgrade to a Zero/Light weight trigger. It works exactly like an L96 trigger instead and can handle any spring without any wear. Instead of holding the piston at angle, there is a cam that lock the piston perpendicularly (sp?) to the sear, then the trigger sear is just in the way of the rotation. That gives a very smooth and easy trigger pull, and sudden release of the piston. It is mechanically efficient versus the VSR-type trigger.