Marlin 336 Firing Pin

Part of my service as a firearms technician includes sighting in all manner of guns. This picks up markedly as the firearms deer season nears. It was such an occasion when a hunter brought in a Marlin Model 336 lever action chambered in .30-30 Winchester. The rifle had been regularly sighted in for the past several years, requiring but a shot or two to attain zero.

As I chambered around I looked his way and said, "The old 336 is about as dependable a rifle as a hunter can carry afield." Moments later, as I pulled the trigger, the rifle failed to fire. Ire-cocked the hammer and… nothing! The same thing happened with the next cartridge. There wasn’t even a firing pin mark on the primer. On initial inspection it was determined the end of the firing pin had broken off, including that portion from the tip taper extending out through the bolt face.

This is a highly unusual occurrence with the Marlin 336. These firing pins are A good deal of precision workmanship goes into such apart. Part measures 3.722 inches in length. Tip breakage of this part is a rare occurrence. made of semi-hardened steel, about the hardness of an ordinary knife blade, but not so hard a standard file won’t remove metal from it. Dry firing a rifle can eventually break a firing pin, but this wasn’t the case here as this rifle hadn’t been dry fired.

Bolt/Firing Pin Removal Only partial disassembly of the rifle is necessary to remove and replace the firing pin. This will include removing the bolt from the rifle, which is quite uncomplicated. Always be sure the rifle has no rounds in the chamber or magazine. Lower the finger lever and remove the lever screw located on the lever tang beneath the receiver. The bolt assembly can then be withdrawn from the receiver. The bolt consists of seven parts including the bolt body.

To disas- Below that, an exploded view of Marlin Model 336 bolt. (1) rear firing pin, (2) front firing pin, (3) firing pin spring, (4) rear firing pin retaining pin, (5) front firing pin retaining pin, (6) breech bolt. semble the bolt, first remove the spring-loaded extractor from its race and set it aside. There are actually two firing pins (the front and rear) retained by separate retaining pins that fit the race within each respective firing pin. The rear (shorter) firing pin retaining pin is removed first.

Be careful to drive the retaining pins straight out with a properly-sized punch. The main or longer firing pin retaining pin is then driven out releasing the two firing pins and the firing pin spring (a flat, curved, leaftype spring). Inspect the parts carefully for breakage or excessive wear. On the rifle described here, the firing pin tip was totally broken off, leaving only jagged edges, however, it was the only part in need of replacement. (Continued on page 23)

Firing Pin Parts Replacement Reassembly of the Model 336 firing pins and spring are in reverse order of take down. As shown by the illustrations, there are five bevels or Lever must be fully closed to fire rifle. Removal of finger lever screw permits removal of lever and withdrawal of bolt. As bolt is removed, ejector can be removed from inside of cartridge port. Note the angled view of rear firing pin through slot at rear underside of bolt. This feature renders the firing pin nonfunctional as bolt is withdrawn.

Underside of bolt cocks the hammer as finger lever is moved downward and forward. Closing of the lever leaves the hammer back, ready to fire, and must be carefully let down with thumb and trigger finger to a safe position if not fired. This maneuver should be practiced with an unloaded gun to totally familiarize the safe use of such a hammer. The broken front firing pin is pictured below the trigger here. cutouts in the primary (front) firing pin.

The spring unites and aligns the two firing pins, allowing the rear firing pin to tip downward as the bolt is fully withdrawn. The illustration of the withdrawn bolt clearly shows this. Replacement of the firing pin retaining pins and extractor allow the bolt to be started into position, mating and controlled by the finger lever. The finger lever screw replacement finishes the job. The lever should then be worked several times and the hammer let down and tested in half-cocked, safe position.

As I reassemble a rifle, I normally coat the parts with a light film of gun oil. Following this I continued sighting in the rifle. Function was perfect and the hunter was back in the deer woods with no further interruption. Conclusion Each gun we take on is a somewhat different entity. Those appearing simple can sometimes be quite complicated. The Marlin 336 falls somewhere in the middle.

There is a slim chance you’ll ever need to replace a Marlin 336 firing pin but it’s good to know just how to go about it should the need ever arise in your shop. AG