Frankford Arsenal Case Trimmer and Prep Center

For the review I had a friend give me over 100 pieces of 2x fired 243 Winchester brass that needed to be trimmed. Before trimming, all the brass was thoroughly cleaned using stainless steel tumbling media and allowed to dry completely. The proper bushing and collet were selected as mentioned in the previous paragraph. I then followed the instructions to get the trimmer set up.

The bushing and collet were both placed into the case holder assembly and the lock ring was tightened until the plastic collet held the body of the 243 with minimal wiggle. This assembly was then screwed into the unit using a CCW (left handed threads) rotation until the neck of the inserted shell lightly touched the trimmer head.

I then tightened down the second lock ring, pulled the case back out, turned the unit on and reinserted the case to trim it. After a few seconds the motor sounded like it no longer had a load on it and I pulled the case out of the holder assembly and touched it up on the chamfering tools. This first case ended up a little short, but with a few adjustments of the micrometer head my next piece of brass came out right where I wanted it.

To get more familiar with the trimmer, I chose to take a few pieces of brass and experiment with different trimming techniques to find out what was going to give me the best results. I found that pushing the case in too hard produced a big burr on the outside of the case neck that would take a long time to remove and made the machine sound like it was being overworked. Pushing the case in with fairly light but constant pressure created smaller burrs and gave me 3 cases in a row with measurements between 2.035-2.038 so I considered the machine ready to roll.

I ran 100 cases through the trimmer and fully deburred them as part of the process. Using light pressure and a ½ turn of the case at the end of trimming I was producing cases that were fairly easy to deburr and looked very nice. The best part was it only took me only 35 minutes to complete all 100 cases!

Next I measured all the trimmed cases and was a little surprised with the results. My minimum case length was 2.030”, maximum was 2.048” and average was 2.039” with a standard deviation of .005”. I found 34% of the cases were over my predetermined reject length of 2.040” and all of these long cases were trimmed again. After the second trimming, all but one of the retrimmed cases now measured less than 2.040”.

After this initial batch of brass I was not impressed with the trimmer. The results I got were worse than I expected and any time saved went out the window if I was going to have to retrim over 30% of my cases on every batch. I thought of possible causes of the inconsistent trimming and figured I might be using bad technique or maybe I had cases that had inconsistent shoulders. I didn’t have a shoulder gauge to measure the distance to the shoulder on the 243 cases so I decided to reevaluate the system again on another occasion.