Reamer/throat for 7SAUM with 180 Hybrids

[ormandj]

I want to chamber a barrel I have for a long-action build I’m doing with 7 SAUM, to primarily shoot 180 Hybrids. Unfortunately, I don’t have any 7 SAUM brass (ADG won’t be producing another batch for some time) and don’t have any 180 Hybrids (haven’t been able to find them in months). This is my first 7mm, so I only have a few 175 Hunters I was able to find on the classifieds.

What reamer specifications are people using for 7SAUM builds with long-action magazines, who are running 180 hybrids? I want to check against my calculations to ensure I get the right JGS reamer machined before chambering. I’m sure they’d help out too, I just figured I’d ask here first.

Is anybody doing any modifications to improve the case, as well, or just leaving it stock dimensions?

 

[Jrebyank777]

I am in the same boat here and have the same questions. In

 

[4O6shootist]

The 180hyb has a very short bearing surface, 100k freebore will work well with it in a saum. However you go to different bullets and that dimension quickly starts pushing bearing surface below the neck shoulder junction. Personally if I had a reamer cut to run 175eh, 180hyb,184hyb itd be 180-200k freebore.

 

[Raffy]

Your safe with 180 freebore for the 180 hybrids. I had a reamer cut from dummy rounds that would accomodate both the 180 hybrid and the 180 eldm. My freebore is 221. The eldm barely makes it so the bearing surface is *just* above the shoulder neck junction, but the bearing surface on the hybrid starts a little under midway up the caseneck and still has 40 thou jump to the lands. It surprised me how different the freebore requirements for the hybrid and the eldm were. The 180 eldm is still long but has a stumpy nose.