Home Forums Hunting & Shooting Hunting Rifles Kimber 8400 magnum ultra mag

Thinking about buying a used kimber 8400 magnum, and having it rebarreled to 7mm RUM. I have a kimber 8400 wsm in 7mm WSM. I love the 3.05" magazine box. Wanting to know how long the magazine box is in a 8400 magnum. Hoping it is longer than 3.60". Thanks

The maximum mag box length in my 8400 .338WM is 3.390".

I load my 250 gn partitions to 3.365 in my Montana 8400 338WM. I think that's pretty close to max COAL to make sure they don't bind up in there. That would be a big problem with the blind mag. Neat idea I've never seen it done. Sounds like they are a little shorter than you were hoping though.

Don't think you'll have the length for a RUM case in there

That's kind of a bummer. I remember reading when they first came out that they would have a 375 H&H length magazine (before the Talkeetna was announced). I'd be a buyer if Kimber made a montana in any of the ultra mags, or even the 375 or 416 ruger!

Mill out the mag box pocket then use a cutoff wheel and cut the box in half and add a peice walla a TIG welder and have your length you desire

I'm going to have my gunsmith do just that and remove the pocket, or spacer, or whatever you want to call it that takes up 0.2"+ at the rear of the box. Mine was re-barreled to a 7 Mashburn and I want the extra room for the long vlds.

https://www.24hourcampfire.com/ubbth...on_Mag_box_ejector_mod_on_Ki#Post7189586

What about putting a magazine box from a talkeetna or caprivi? It has to be long enough, they are chambered in 375 h&h, 416 rem mag, and 458 Lott. Does the 338 win mag have a spacer in the back of the mag box that could be removed?

I'd do like Smoke did and go Mashburn Super

Dober

375 or 416 Ruger would be easy, just re-barrel the 8400 Magnum...of course you're buying a real expensive rifle just for the purpose of a re-barrel. Not sure I'd be a real fan of shooting a near 7lbs all up big bore though lol

I don't want a 375 or 416, was wanting to rechamber a 7 rem mag to a 7 RUM.

Are those built on the same action? How long are the mag. boxes?

Nothing wrong about a handloaded 7 RM.

Old thread but curious if anyone has done this and has info or updates. Did the H&H mag box work??

Today, I would just go 28 Nosler. No muss, no fuss.

Will the loaded RUM eject without milling a relief in the ejection port?

Yep.

Was really looking at possibility of a 300 rum. Wondering if it would be possible off this platform. If nothing else maybe a custom throat win mag for 215 Bergers and max mag box length.

I'm about to list my Talkeetna for sale........................

I removed the spacer in a 8400 action and it gave me a total length of 3.67" (a few taps with a hammer and a twist with a flat sd). I hunted with it for a few months now with the follower as is and have not had a single feeding problem.