Knight Ignition Improvement

Faulty primer ignition can originate from a number of causes. Chief among these are impeded firing pin thrust, which may come from sluggish spring pres- Bottom: Disassembled view of the Knight muzzleloader bolt shows nose of firing pin. Firing pin travel is very short on this type of rifle. sure. This can stem from too short a spring or a spring that is weak. There also may be a hysteresis factor where spring bind or cocking piece friction is present.

Where correction of these factors is obviated, it may be time to The primer is contained in this jacket. Bottom: The rifle bolt with a loaded Full Plastic Jacket as used in Knight DISC muzzleloader rifles. take a close look at the firing pin tip for both shape or depth. A customer presented me with a .52 caliber Knight DISC Extreme muzzleloader that had erratic ignition, particularly in cold weather.

By design, the bolt on this rifle is equipped to utilize a standard 209 shotgun primer encircled by a Full Plastic Jacket that seals the primer. The firing pin is also designed to use a Number 11 percussion cap with the same firing pin nose radius of 0.168". While a nose radius of this diameter may be suitable for musket cap ignition, it appears poorly suited for shotgun primer ignition as it often fails to crush the primer mixture against the anvil with full effectiveness.

This is particularly true in cold temperatures as are routinely encountered during many hunting seasons in the north. On closer examination of the firing pin nose tip compared with that of a standard shotgun firing pin, a major difference in diameter was noted. The Knight’s firing pin measures a full 0.168" across the extreme borders of the primary firing pin protrusion. By comparison, a standard shotgun firing pin radius is much smaller, measuring at 0.110".

Primer is shown loaded in the Full Plastic Jacket with the tip of original firing pin taped to side. Above center: Knight DISC Extreme firing pin set up in a lathe in preparation for tip modifications. The solution was a firing pin nose tip conversion. A plan was presented to the customer whereby the firing pin nose tip would be reduced from 0.168 to 0.110 and properly radiused. This would result in 0.060 radius tip protrusion beyond the bolt face.

The work was performed in a lathe, conveniently accomplished with the back portion of the bolt centered and held in the lathe chuck and the rounded end of the firing pin shoulder centered in the roller bearing lathe center rest. A properly sharpened tool bit was used to reduce the diameter of the firing pin nose tip from 0.168 to 0.110. Following the lathe, a fine machinist file Below center: These two Knight DISC Extreme rifle bolts show the work performed on the firing pin.

On left, the original configuration of firing pin. On right, the re-shaped firing pin tip with 0.168" radiused diameter and 0.060" length. was used in forming the radius on the new tip and finally polished with 600 grit paper. On firing, the nose tip imparted a precise 0.060" indentation flush with the surface of the primer. Testing In testing the reworked firing pin there was no question about the improved functionality of the newlyformed nose tip.

It was tested on a cold day at a temperature near zero Fahrenheit with Remington 209 and CCI 209-M Magnum primers, Blackhorn 209 powder, and 325 grain Hornady bullets. Primer ignition was vastly improved, along with much better grouping on target. There was no longer any sign of hangfires or misfires even in the frigid temperatures. As a means of improving ignition reliability on the Knight DISC Extreme muzzleloader, I can strongly recommend this firing pin nose tip modification.

For best performance, the tolerances should be held as closely as possible to those described herein. Sometimes a small change can make a big difference in performance, as was the case here. AG