You may have a couple of concerns with the feedneck of your 98 Custom that I can help you resolve with a couple of simple mods that may take you all of 15 - 20 minutes to perform. Are you having some chopping concerns and does the feedneck feel as though it's going to fall off wobbling all over the place when you're running with it on the field? If you said yes to either or both of those questions a couple of simple mods can alleviate those concerns.

Chopping

The stock delrin bolt of the 98C is just a simple tube that has an o-ring on the forward end with a protruding boss for the linkage arm. It reciprocates along the power tube which is an integral part of the valve that delivers the pressure to the paintball. The pressure exerted from the power tube pushes the ball forward in the barrel but there's no seal at the back portion of the bolt. This means that any excess back pressure can actually be blown back into the marker through the back of the bolt. This excess pressure will actually funnel into the feedneck and blow the paintballs waiting to be fed, back into the hopper. Unless it's a force fed hopper, this in turn will cause a hesitation in the drop of the next ball to be fed. If a ball is only half fed into the breech, the bolt will chop it. This is actually quite a common concern in blowback style marker design but the 98C's particular design may be a little more extreme than others.

Resolve: You need to find a way to purge this excess pressure from the feedneck somehow. This can easily be resolved by drilling a hole or a few holes in the feedneck. You can use a smaller drill bit like 1/16" or 1/8" to drill a few holes or 3/16" or 1/4" for a larger single hole. As you can see in the photograph above, I just chose to drill one single 3/16" hole in the side and it did the trick for me. You can drill the hole(s) in the side or back portion of the feedneck to relieve this phenomenon. Drilling these holes may render the feedneck more susceptible to exposing the paintballs to water if it rains while you're playing but chances are you'll be playing less in the rain than not.

Wobble

As I mentioned earlier, the configuration of the 98C's feedneck is a good design. You can just depress the front site, push the feedneck to the side in case of a chopped ball. This is a nice option if you use a pull through squeegie. The problem with this design is Tippmann didn't make the fit to any sort of close tolerance. This means that when you have an attached hopper, the feedneck wobbles and is a bit annoying especially when you're running with it.

Resolve: You can just find a relatively thin o-ring and stretch it over the bottom portion of the feedneck so one half of the o-ring is between the body and feedneck. Look in the photograph above to get an idea of what I mean. This will alleviate any wobble concerns that you may have. Use an o-ring about the size of a C02 bottle o-ring. When stretching it, take your time because if you stretch it quickly, chances are that it will snap in half. It took me a few attempts before the o-ring didn't break when doing this to mine. Heating the o-ring with a hair dryer may ease the o-rings elasticity temporarily long enough to stretch it over the bottom portion of the feedneck. I used a black o-ring that I purchased from a local hardware store that matched the color of the feedneck.

A couple of simple modifications that shouldn't take you too long to perform that will rid your 98 Custom of these concerns.

Technical Information