Benefits of Topline Porting and the Porting Process

Our business was created to meet the immediate need of all shooters, and to bring the business full time to the appropriate site--the shoots. Our patterns were developed at the request of shooters and based on empirical data compiled mainly from outstanding engineering and physics departments of major universities throughout the United States, using a seventy year old process called Electrical Discharge Machining (EDM). Top Line is involved only in the porting of shotgun, and rifle barrels. We are committed to this portion of the industry. We were the fIrst to bring the EDM process to the shooter on-site in 1990

EDM Process

EDM was developed in Europe by the Germans in the late 1920's and early 1930's. The process is unique in that the application we use on barrels, commonly called the "sinker" method, operates at ambient temperatures. It is a spark erosion process and there is no heat involved. That is why blueing is not disturbed in any way. Nothing mechanical occurs to cause burrs because no abrasive surfaces rub or cut against one another.

What does porting do for you?

Porting was designed initially to eliminate barrel air turbulence. The rest of the benefits are peripheral. The effect of porting essentially spreads the recoil time out over a longer period of time, which for the most people reduces perceived recoil about 15 - 20%. Additionally, gun motion is reduced about 85 - 90%.

• The standard pattern consists of five teardrop shaped ports on each side of the barrel. Our unique shape allows the placement to be higher on the barrel. The higher the pattern, the more effective the result.
• The extended pattern consists of two additional ports at the back end of the pattern. This pattern is the preferred choice for many who shoot heavier loads for pigeons or game hunting.
• Ports are smaller elliptical holes(not teardrop). The number of holes depends on barrel length and caliber. Eliminates 15% to 20% of recoil.

Ask us about our unique shape and pattern that gives more effective results!