New piston head shaft too large for old piston.

[porkchopz28]

This has been solved, thanks for your help.

I bought a bore up kit with silent piston head and when I went to install it the shaft on the new piston head is a bit larger than the current hole that is in the piston. It's hard to tell how much larger the shaft is maybe 3/16th of an inch. The piston head comes with a bushing and barrings that sit inside the piston.

Am I correct in thinking that it will be OK to drill the hole in the piston to a larger diameter to accommodate the larger shaft? But before I even go through the trouble of modifying the piston, should it have more than the last tooth metal, I also added a heaver spring it's a M120 now.

I'm working on V2 classic army, the bore up kit is also classic army I'm thinking the piston is stock.

Thanks for your help.

[Stealth]

Let's take a step back, why are you installing a Bore-up Kit if you're running only an M120 spring? Are you using a barrel that's significantly >> 509mm in length?

Provided the piston is of decent quality, enlarging the hole should pose no issues. Ensure that the piston head is firmly secured to the piston body. Use blue loctite on the screw.

The number of metal teeth varies from piston to piston, but in general it is pointless to have more than one metal tooth, unless you are attempting to do a short-stroke setup and/or using dual-sector gears where you would be removing teeth from the piston. More metal on the piston = more mass = additional strain on your mechbox.

[SuperHog]

Before you do any modifications, check the diameter of the holes. Most stuff made off-shore are not in spec anyways. I had a similar issue, that the piston and piston head was just too tight.

If you drill the piston off center, you will have other issues when you put your GB back together.

If the piston shaft is 3/16 too large, then have it turned down on a lathe so it will be true.

[porkchopz28]

Problem solved it was the OEM piston, bought a new one rather than modifying the old one. The old one has a really good air seal on it maybe I can use it for a low fps CQB gun down the road if need be.

[porkchopz28]

Originally Posted by Stealth

Let's take a step back, why are you installing a Bore-up Kit if you're running only an M120 spring? Are you using a barrel that's significantly >> 509mm in length?

The bore up kit is a little misleading, the cylinder is ported and adds very little in the way of volume.