Gunsmithing 300 WSM reamer/freebore questions

[Iamero]

Hey guys, quick question for those that run/have built a 300 WSM recently. I am wondering what you guys are running for freebore for the heavier bullets like the 200 ELDx and 208 ELDM (I have no intention of going 225-230gr at this time). I'll be using the ARC mags which will allow me OAL of around 2.97". I did a little reading on what I could find and I've seen some people say they use .055 freebore but most seem to be .100 to .155 freebore.

Let's hear some feedback from real world trials (would love to see some load data too if you have that).

 

[Clint E.]

I am not an expert, but I had a 300 WSM built on a short action this year, with intentions to shoot 215 berger hybrid.
I think that you want a SAAMI spec chamber if running on a short action at mag length. My rational is that the SAAMI chamber basically has zero freebore, which is good because you wont get close to the lands with the 200gn class bullets at mag length anyways so any extra freebore will just add to the bullet jump. Check this article out, it discusses the reamer specs at the beginning. If you were running it on a long action I think you would then want some extra freebore to seat things out further.

https://www.loaddata.com/articles/PDF/3-Inch%20300%20WSM.pdf

I should add that I have Berger 215 hybrids loaded at 2.90" and am not into the lands in my SAAMI chamber.

 

[flyfisherman246]

I am running a SAAMI spec zero freebore .300 WSM in a short action with a notch cut in the feed ramp and shooing accurate mags. I am loading 2.950" OAL with a 208 ELDM and it is jumping .040". So 2.990 would be touching a zero freebore with 208 ELDM. Hope that helps.