I have both 6 mm and 22 Creedmoors. I resize the once fired brass from the 6 mm (Hornady 6 mm brass) in a Redding FL die with a .254 bushing. I use a Hornady seating die I cobbled together after calling them and ordering different pieces and parts. I'm running it on an xray chassis with ASIC mags and haven't had a single issue with feeding.
What I've found so far is whatever works in the 6 mm works in the 22 within a .5 grain or so. I've used 4831SC, R26, MRP and Retumbo with both 75 AMAX and 77 TMK's. All three use roughly 45 grains of powder in either load. 47 grains of MRP fills the case to the top, 46 gets to the neck/shoulder and 45 is just below the shoulder.
The TMK's for whatever reason are a bit faster by about 50 fps. I get 3600 fps with the 77's and 46 grains of MRP in my 23" barrel. I've settled on 45 grains for 3545 fps.
With both rifles sighted at 100 yards, the 6 mm requires 29 clicks on my Nightforce mil scope at 600 yards with a 105 Hybrid at 3050 fps. The 22 requires only 19 clicks with the same scope. Both seem to buck the wind about the same but the 22 is flatter.
My gunsmith simply took a 6 mm Creedmoor case, necked it to 22 and sent it in to have a reamer built. Accuracy is fantastic.
I've already got a spare barrel figuring I'll burn it up quickly since I just shoot it and don't baby it. I'll probably set the new barrel at 19 or 20 inches. From what I've been able to find, an 18" barrel doesn't lose too much from a 22" barrel with the 22.
Last edited by parshal; 07/01/16.
