Shortened spring = higher force to paintballs?

So my main gun is a pump mag, and this last weekend I was having some real problems with broken paint. It's a classic valve LVL 7 pump in a z body. I have a foamied Venturi ANS bolt in it. I was shooting Hell Survivors red marbz, and it was between 55 and 68 degrees while playing. Some of the things I tried to fix it:

- using a wider bore insert (went from 684 to 687 and then to 693)
- swapped out the foamie bolt for a non foamie venturi (the foamie is a little worn down)
- turned down the velocity
- switched to semi auto (removed wave spring and put in standard length main spring)

Aside from some double feeding issues from a sticky detention, I notice that I had no breaks once I switched to semi auto. This would indicate to me that my trimmed mainspring is not "restraining" the bolt enough when the gun is firing, resulting in breakage even in a semi cold day. The same set up with the same spring worked fine on a day in the low 80s in July (two days straight actually - Global Survivors).

Does anyone have thoughts to share, or critiques of my hypothesis regarding the shortened mainspring?

i would suspect the paint (could be defective) or the non-agd bolt before the spring. some of those those venturi bolts aren't really long enough, and allow the ball to roll back a little bit. this let the next ball in the stack sit lower, so when you fire the bolt could clip that ball, damaging it, which then results in it breaking apart when it's fired.

see if you have the same issues using a stock agd bolt, or different paint (to rule out the possibility of defective paint with weak seams). as for your spring theory, i don't think it matters, but it takes no effort to throw in a good spring and test that out too. may as well, right?

I use a lvl 7 foamy bolt in all of my pump mags. It makes a huge difference. But your initial assumption that the bolt hits the ball a little harder is correct also.

Depending on what type of body you are using, the detents can play a big role too.

If you are using small bore paint and/or if the paint is allowed to roll back, then the bolt can clip the next ball in the stack causing it to fracture. That can cause the next ball to break as you are firing it. Using a short spring does cause the bolt to hit with more force, so the next ball in the stack will get hit harder in that scenario.

Quote:

---

Originally Posted by Cyco-Dude

i would suspect the paint (could be defective) or the non-agd bolt before the spring. some of those those venturi bolts aren't really long enough, and allow the ball to roll back a little bit. this let the next ball in the stack sit lower, so when you fire the bolt could clip that ball, damaging it, which then results in it breaking apart when it's fired.

---

Thanks for the tip. I have a digital caliper to measure, but I don't have a stock bolt. Does anyone know the length of a standard LVL 7 off hand? I have a LVL 10, but I'm not sure they're the same overall length. I also suspect that a slightly flattened foamie would have contributed to the "shortening" effect.

I also think the z body and the apparently deficient detent (even with a Kila magnetic) may have contributed to the issue because I was getting some double and even one triple feed.

Damn irresistible vintage bodies.

Thanks all for the input. I will continue my investigations and let you know.