I have loaded rounds with a COL of up to 1.70" -- more than that and I run into a chance with some bullets getting stuck in the lands. I tried the C-products 5.45 mag and it did not work well for me so I tried the 20 round Magpul Pmag. I have only loaded 5 or 6 rounds maximum in the Pmag each time I'd be testing a load. I will say that the Pmag has worked perfect for me in this type of load testing. I have even used standard length loads with a COL of 1.36" and loaded 6 rounds and the magazine functioned perfect on each test. The reason I've posted this is some people may wish to try rounds loaded to a COL that will not fit in a PPS-43 magazine and don't want to single load the rounds. The C-products mag did work but some different length rounds gave me some jams -- I have not had that problem with the Pmag.