Typically when you look for an aftermarket bold they are advertised as either a straight shot or as having a Venturi insert. Straight shot bolts are bolts that are an open tube design with no obstruction between the ball and airflow.  Venturi bolts have either an insert or cover that restricts the airflow into a pattern (usually a variant or series of holes). So what is the pros and cons of each design?

Straight Shot

Straight shot bolts are usually included on a gun stock.  Guns such as the Hammer, Autococker, Automag, Tippmann Pro-Lite/68 Carbine, come with straight shot bolts.  This bolt design was the original concept in the paintball design
originally appearing in the bolt action Nelspot 007 (one of the first markers).  The design of non-obstructive airflow is said to
allow more air flow to the ball giving an increase in velocity.  Also a straight shot bolt consists of less metal allowing for less weight and a higher rate of recocking and firing (at least when heavier bolts drag).  The draw backs of the straight shot design were typically, the inconsistency of ball velocity, and that hard burst of air released on the ball.  This "solid burst" sometime tends to warp the ball decreasing distance accuracy and sometimes resulting in ball breakage.

Venturi

The concept of a Venturi bolt is very simple and quite ingenious.  With the drawbacks of the straight shot, being mentioned above, the venturi setout to fix this.  The Venturi insert in such bolts, as the Bob Long Cyclone, allow for the air to be dispersed along the entire surface of the ball.  This lessens the "smack" against the ball, reducing warping.  This means longer range, more
consistent velocity, and better distance.  Yet, on some Venturi bolts, you will experience a loss of velocity in your marker, but this only means a small adjustment at the chrono.

So which to buy...?

Overall the performance and price weighs in the favor of Venturi.  First, there aren't many places that produce aftermarket bolts that are straight shot.  Second, the reason they don't is because Venturi gives you the better performance.  With better gas efficiency, distance, and velocity the Venturi is the overwhelming choice.  I suggest either the Bob Long Cyclone Bolt series, or the Starfire Bolt series.  The Bob Long uses a spiral insert that also places back-spin on the paintball.  The Starfire series have a cover plate which with a five hole design drilled in it.  This pattern creates a even air distribution over the ball.  Both are around $25-$35 and are worth the price.

Tony Sasso
MPN Columnist