Here, I will tell you how to make improvements on a good performing bolt into a great performing bolt. I will show you how to take the venturi out and make the stock bolt more paintball friendly. You can make your bolt rear cocking if not already by looking at my Rear-Cocking rod article. You do not need to do all of these modifications. Do just one if you want. At least do the second part of this modification of sanding the inside lip.

Remove all air and paint prior to doing this modification. Read the instructions through. Make sure you have an understanding on what is involved in doing and what is needed for a trigger modification. If you attempt to do any of the home modifications listed on this site, I am not responsible for any damage done to, or from, modifying your marker. Also, by doing any of these modifications, you will void warranty of the marker. Kingman does not support the home modifications that I share.

• The Venturi

I like to call this the "Poor Man's Lightening Bolt" modification. The reason is I say that is because it will resemble the AKA Lightening bolt. This is a very simple modification that is done to a bolt that has a removable venturi like what is on a stock bolts and Bob Long Cyclone bolts. What this entails is to remove the venturi from the inside of the bolt. Why do it?

Well, the Venturi is why! Since I have been playing back in the mid 80's, the venturi bolt has been a questionable theory that is still in question with paintballers that like to squeeze every ounce of performance out of there marker. You may not want to do this modification at all. That is fine. It is your decision. Either way, it will not hurt the marker.

What is the venturi? The pic above shows the front end of a stock bolt. See that star thing in the center? That is the venturi that we will be removing. /P>

There are many forms of venturi that are made. The picture above shows three types of a venturis that you can find in a Spyder bolt. The one in the bottom is a first generation venturi found in the older Spyders. Kingman re-designed the venturi to reduce the costs of cutting the curved "slots". This is the 2nd generation venturi pictured on the top. The one in the middle was a transitional phase. It is simply a 4-pointed metal stamping.

Notice also the needle nose plyers on the left side of the picture. The first generation venturi could be removed using the one at the top. But, the middle and top venturis are mounted deeper in the bolt. So, the thinner one pictured on the bottom is needed.

What the venturi is advertised to do is to disrupt the air flow and make the air hit the paintball more evenly and to cause less ball breaks as compared to a non-venturi bolt. I do not believe this at all. I have tried pretty much every bolt and have gotten equal ball breaks with them. Most ball breaks is contributed to the balls not feeding fast enough or an improper paint to barrel match. I also found that you need more air to get through the venturi before hitting the ball. Not exactly air efficient. As far as hitting the ball evenly, not much of a concern in such a small area. By the time the ball gets to about 1"-2" down the barrel, there is equal amount of air all around the back of the ball. And contrary to many beliefs, paintballs do not deform that bad. Again, by the time the ball is about 2" down the barrel, it is in its natural shape.

As I have said, this has been a debatable subject ever since the venturi came into the picture. When I removed the venturi, many others and I have experienced an increase in the velocity by as much as 10fps. This increase in velocity will require you to reduce the tension in the main spring. Thus, less air used.

For those that want to convert their Spyder to LP as inexpensively as possible, removing the venturi is a must! Either that, or spend the money and get the AKA Lightening bolt.

Removing the venturi is an inexpensive alternative to purchasing the AKA Lightening bolt. The Lightening bolt has a large hole in it that has no venturi at all. It is an open space from where the air enters the bolt to the back of the ball. No venturi equals less restriction that enables lower operating pressure. I am not going to get into LP in this how to. But go to my Low Pressure - F.A.Q. for an explanation.

Onto the bolt mod...

What you will need is a heat source, needle nose pliers, regular pliers or a vice, and muscles. You will also need some sand paper (about 200-400 grit) to finish the job. A dremel tool is also helpful.

Take out your bolt from your marker. Carefully, take off the o-rings and set them aside.

Secure the bolt in a vice or grip it with regular pliers by the bolt pin. Do not grip the bolt body. Putting scratches on the outside of the bolt could cause the bolt to get stuck inside the marker. If you do get a scratch on it, sand it smooth. Next, insert your needle nose pliers and turn counter-clockwise when looking at the venturi.

For those stuborn venturis, it is probably held in place with LocTite. If this is the case, simply hold the bolt over an open flame (candle, lighter, or torch). Heat the area just inside the hole where the gas enters. Careful! The bolt will get hot. Heat for about a minute or two. Twist out. You may have to reheat a few times to soften the lock tight. But the venturi will come out. And be careful not to scratch the body. For some, you may need to continue heating the venturi at the same time you twist.

The hole that is now present needs not be filled in with anything. It really doesn’t effect the airflow. You're done with this portion of the modification in this article. Proceed to have a paint friendly bolt.

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• More paintball friendly

Wipe off the soot from the bolt if you had to heat it while taking the venturi out. Just some final finishing is left to do. Look at your now empty bolt hole. Where the paintballs rest, there is a semi-sharp edge. Take your sandpaper and sand the inside lip. This will enable the bolt to cup the paintball gentler then before. A Dremel tool with a grinding wheel helps in this. You may still need to use some sandpaper to get rid of any sharp edges.

Wipe off the sanding residue and any other soot on the body. Replace the o-rings and oil them until moist. Put your marker back together. Poor man's Lightening bolt mod finished!!

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