Chamber & Tooling Size Variation

Handloading for the 38 WCF cartridge has been a lot of fun both with smokeless propellant as well as with Holy Black in both real Black Powder and Pyrodex. Nothing seemed amiss until I added another 38 WCF firearm to the stable. Initially I was shooting the cartridges in an Uberti 1866 rifle and cartridges made with virgin brass from Starline and those made with my Lee 3-die reloading set cycled, chambered and fired just fine in the rifle.

When I tried to chamber the reloaded cartridges into an Uberti 1873 revolver, things went array. The cartridges simply would not chamber fully into the revolver and were sticking out at the rear for .040” (about half of the rim thickness) preventing cylinder rotation. At first I though the .401 bullet was giving me fits but I soon determined this was not the issue. Either the cartridge base was too wide or the shoulder was the problem.

Observation of virgin brass compared to my “Full Length Resized” brass confirmed the Lee resize die was acting as a “Neck Size” die with little to no resizing of the shoulder or base of the case. Measurements indicated the fire-formed forward moved shoulder (as observed) was appropriate. Reading and studying the subject revealed that virgin brass had a shoulder set way aft to allow the assembled cartridges (with virgin brass) to chamber in a plethora of original and reproduction firearms. In fact, the shoulder on virgin brass is almost indistinguishable on the case.

After comparing fired cases from both the rifle and the revolver against each other, it seemed the now fireformed cases from the revolver has longer necks, meaning the shoulder was farther aft on the case. Measurement revealed that the shoulder was in fact farther aft by .040” (forty thousand). It was apparent that the Full Length Resize die was not setting the shoulder back far enough on fired brass to allow the newly formed cartridges to chamber in the revolver. Either the die was a tad off or the chamber was a tad too shallow.

I decided to try dropping the die downward, thereby setting the shoulder farther aft on resized cases. Since the die was mating with the shell holder, the bottom of the die would need to be trimmed. Not having a lathe to knock .040” off the die, I fired up the bench grinder to grind off some metal. I realized at this point in life that rather than taking chemistry and physics in school, I would have been a lot happier taking shop class. Perhaps I would have had a lathe by now. Regardless, the grinder worked and provided me with a working trimmed resizing die.

I fired some cartridges in the rifle and resized/reloaded them with my modified size die. The cartridges dropped right into the revolver chamber like virgin brass. Inspection of the resized brass with the modified resize die revealed that the shoulder is set back farther aft on the case allowing chambering in both of my firearms.

I will never determine which object is out of spec, the revolver chamber or the size die. It could actually be that both the chamber and the size die were at the far end of the tolerance table. I don’t really care to spend any time figuring this out since the problem has been resolved with a die modification.

The funny thing is that after seeing the rough finish on the mouth of my modified die, it kept working on me to clean that up. Without a lathe, this task was near impossible. I contacted a Tool & Die shop near me and those rascals cleaned up the mouth of the die on their lathe for a very modest fee. You would never know that die has been bench ground! I was also provided a tour of the shop and I have to admit, it was very impressive. I didn’t even recognize most of the machinery in there and just nodded my head when the shop owner described what they are. A wire lathe? You got me. It sure looked EXPENSIVE though. It cuts metal with a wire strand, I think.

Anyway, here are some pictures of the cases for you to view. Those of you who shoot the 38 WCF will be familiar with the images.