I use the HCA mags in my 7 SAUM as well. Tikka PRC mags weren't a thing when I built it. They work well with the 175/180 class bullets loaded to 3.1ish COAL but do not feed well with 145 CEB lazers at just under 3.0" COAL.
Looking forward to hearing what others have to say as it might be a good option for my shorter light bullet ammo. Id think the 6 UM users experience around here would extrapolate well to what OP is looking to do?