300 BlkOut Case Trimmer

thingiverse

There are many trimming jigs available for turning 300 Blackout brass into 223 cases. Most are designed specifically for the mini chop saw sold by Harbor Freight. I had used that chop saw for a day until it overheated and stopped working, so I returned it and bought the next larger size. The standard cutting jig worked fine, but the cut-off brass ends would frequently get stuck in the vise on the saw. I'd have to stop every 20 cases to clean out the brass ends. To solve this problem, I decided to build a jig that would send the ends flying using the bigger cop saw. Using the jig: Line up the cop saw blade with the case-holding side of the jig, and it will cut off about 1.389". Then you can trim down and clean up the case to under 1.368". I could have made it cut shorter, but I wanted to leave room for fine-tuning the cases I use, and the chop saw blade used is a rough-cutting tool. There isn't a stop that will prevent the blade from cutting the jig in half, so just stop after you've cut through the brass. I'm working on additional features for this jig, including a case-hold down support and a better cut-end deflector to keep the ends out of the way. I also plan to add a blade stop to ensure the jig isn't cut in half. Remember to use safety gear and practice safe power tool usage.