I didn’t see a topic specific to the Cortina Precision mandrel dies, and now that I’ve gotten to use it a bit (350 rounds-ish), I thought I’d share a couple observations and open the discussion for anyone that may be considering these dies.
My primary interest was in the mandrels/armoloy coating, however one of the selling points of this die is that it also acts as a base sizer die. In the product video, it is described as “the same as your sizing die” and “not a small base die.” Supposedly it will help with “clickers,” which has been an issue with some chamberings. I’ve never had a clicker that wasn’t a snipershide level pissing hot handload (with no pressure signs, of course), but I figured there may be some merit to holding the base of the case during the mandrel operation so I ordered a 308 win family die as well.
Fit/finish on the dies and mandrels are very nice. The inside is smooth, and sizes smoothly. I like the wrench flats and wrench holes on the lockring. The lockring has two sides, one rounded, and one squared that is allegedly machined true to the threads and perfectly square. I have no way to test it, but it sounds good. There are two set screws on the lockring. Mine came so loaded with yellow threadlocker that I couldn’t screw them in far enough to engage the die and stop it from spinning using a standard allen key. I cleaned most of the threadlocker off so that I could use the set screws.
I’m using this die to resize Lapua 6mm Creedmoor brass. It has been fired 10x in a standard PVA chamber and has never been annealed. There is a Mighty Armory FL sizer in station 1 (mandrel/decapper removed), and the Cortina die in station 3 of a 550. I measured several pieces of brass from fired, resized, and after the mandrel operation using Mitutoyo calipers.
Body diameter at the .200 line (ish)
Fired - .471
Resized MA - .470
Resized + Cortina - .469
For comparison, CIP/SAAMI maximum cartridge drawings put the base diameter at .4708” and .4703”.
With it squeezing an extra thousandth after I set the shoulder back, I did see headspace grow .0005” after the mandrel die. I did not think to measure overall lengths while I was reloading. I may next time just for giggles. Visually, there is a good amount of additional body sizing going on compared to the Mighty Armory die. The sizing appears very consistent within my small sample size.
Here’s an example of the base sizing, although it is a 6.5CM not from my rifle and received a little less of a squeeze, it conveys the idea/results...
Overall – It does what it says on the tin. I like the armoloy mandrels. I’m interested in hearing other’s experiences and if the extra base sizing is helping anyone outside of the PRC calibers.
Link to the Product video.
