Kimber 8400 to 300wsm

[280rem]

Wondering how well it would work to rebarrel a kimber 8400 300 win mag to 300 wsm. As a platform to run the Barnes 212 LRX bore rider. I assume the mag rails would need to be tuned to the wider case. Just curious if there is anything that would cause this to not work well? Would it feed well? The 8400M seemed to be a great WSM platform.

 

[thinhorn_AK]

The short mags used a different action than the standard magnum ones. So your project probably won’t work.

 

[Walker6]

Never done it, but seems like an interesting idea..

Case head is a tiny bit larger on the WSM, so maybe you’d have to open up the bolt face a little, but maybe not? Maybe a little less taper on the WSM case, but it’s so short that it might not matter?

If someone had a 300 win mag action, they could stack a few WSM cases down in the belly and see if they hold?

 

[Johnwell]

No experience with the 8400 action, but I built a 300wsm on a weatherby mkV which is also a long action. It was originally a 300wm also. I did the throat with a separate reamer and increased the free bore 0.25” (I think; I don’t have my notes in front of me). I’m using the 208 berger and getting 2775 fps with h4831sc out of a 25” barrel. Could improve that with a different powder but it’s fine for my uses.

Feeding is challenging. Rounds tend to want to nosedive due to the rebated rim/fatter case. I imagine you’d have similar issues with the 8400. I’m planning on either 3d printing or machining a feed ramp for the front of the magazine well to help pick up the nose of the bullet; since I have so much extra room in the mag well.

Didn’t have to do anything to the bolt face, they’re both so close that it doesn’t really seem to matter.

In retrospect, it probably would have been easier to build a PRC instead, but overall I like it.