Kimber Montana Build

Njadams13

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Apr 13, 2022
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Hi guys, looking for some input from some guys who have put similar rifles together.

I just picked up a Montana 8400 in 300 WSM (Yonkers rifle, not threaded).

I do plan on shooting it as is, and if it shoots well, I MAY just have it cut to 20” and threaded for my DD enticer STi.

I am however more interested in rebarreling the rifle. Lilja can cut the factory contour (or one slightly heavier and likely flute it). I have so far looked into 6.5 saum (currently in the lead if anyone knows a good smith for a Montana with the Saum reamer), 6.5 or 7 SS (I had one guy mention the Sherman may not feed reliably in the blind mag), 7 WSM, a faster twisted 270 WSM (if the modern longer bullets like the 170 will fit in the mag, 6.8 western (if it will feet and the coal with the 170 will fit), 6.5 prc.

The internal mag box is right around 3.044.

Looking to see if anyone has any input on the above cartridges in both performance and ability to reliably feed from the blind mag.

This will be an 18.5-20” barrel threaded for a can and will almost exclusively be shot with a suppressor. This is going to be a multi state all game gun. Looking to keep 2000 fps at 600 yards and although I am well aware and understand that energy really does not matter, 1300+ ft pounds of energy at 600. The goal of this is a lightweight mountain rifle in a magnum caliber that I can hunt just about if not everything in North America with, regardless of caliber restriction. I’m sure there are some places that require above .264 for certain species, but I’m not talking about the outliers.

Also. Has anyone used the Warne picatinny bases? The split ones, not the full rail. I assume they are plenty reliable? The leupold full length pic rail currently on the rifle is not only really thick, but makes loading the mag rather difficult. Doesn’t seem to be a ton of options for these. I was hoping Hawkins had some direct mounts for these. I looked into the Talley rings, however I know there are some stories of these failing
 
Probably 2850fps? I’m guessing, based on the 2950fps claims from 22”. Probably a bit more efficient than a 7 PRC and like speeds.

Brass might be problematic but you can resize 300 WSM brass.
 
I would probably go 6.5 PRC in a 20” for ease of use, simple reloading, and availability of factory ammo in a pinch. 147s at 2800fps carry 2000fps and 1300 to almost a grand at 6500’ DA. Would be a lot more comfy to shoot than a 7 WSM with 180s in a Montana weight rifle too.

Leupold backcountry one piece rings are your huckleberry on that gun. Mediums for a 42mm scope.
 
I was wondering this. 7 wsm isn’t listed in hornady’s manual anywhere, and I’m just not sure how fast I can push them from a 20”
Upper 2700s would be top end I’d think. 162s went 2920 in my 20” 7 WSM before I started seeing some pressure.
 
I would probably go 6.5 PRC in a 20” for ease of use, simple reloading, and availability of factory ammo in a pinch. 147s at 2800fps carry 2000fps and 1300 to almost a grand at 6500’ DA. Would be a lot more comfy to shoot than a 7 WSM with 180s in a Montana weight rifle too.

Leupold backcountry one piece rings are your huckleberry on that gun. Mediums for a 42mm scope.
My problem with the leupold is the gross way they hang the ejection port lol.

6.5 prc is appealing, I just have bad experiences with a short PRC not even remotely living to what it should have gotten in theory on accuracy. Thats why the saum is intriguing.
 
ADG is making 7mm-6.5 PRC brass, I imagine 2800 is possible with a 20” and 180s.


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7-6.5 prc is really intriguing. If anyone happens to load for one and could throw a dummy round together seated to neck junction, I’d be curious on the length and if they would fit.
 
My problem with the leupold is the gross way they hang the ejection port lol.

6.5 prc is appealing, I just have bad experiences with a short PRC not even remotely living to what it should have gotten in theory on accuracy. Thats why the saum is intriguing.
On my set on my Kimber 7 WSM, I got pretty aggressive with a grinder and flappy disk on the rear ring and it worked out nicely. Just took a big flat chunk out where it hangs over at a 45*. I’ll see if I have a pic.

I don’t think there’s much reason to think a short SAUM will be more inherently accurate than a PRC. I had a 24” 6,5 SAUM on a Bartlein, and it did hammer and shot 140s at 3100 or so. That wouldn’t be a bad mousetrap at all with ADG brass being available…
 
On my set on my Kimber 7 WSM, I got pretty aggressive with a grinder and flappy disk on the rear ring and it worked out nicely. Just took a big flat chunk out where it hangs over at a 45*. I’ll see if I have a pic.

I don’t think there’s much reason to think a short SAUM will be more inherently accurate than a PRC. I had a 24” 6,5 SAUM on a Bartlein, and it did hammer and shot 140s at 3100 or so. That wouldn’t be a bad mousetrap at all with ADG brass being available…
I ended up grabbing a set of the Warne bases (20% off of $30 for cyber Monday, not losing much if they suck). I imagine bedding them will make them hold up just fine. If they don’t I’ve still got the leupold base I can chop or grab the leupold.

I actually meant to type velocity there. My short prc was an absolute hammer, but at 18” had to be run HARD to get anywhere even close to 2700 with a 140. I just don’t want to experience that again.
 
I ended up grabbing a set of the Warne bases (20% off of $30 for cyber Monday, not losing much if they suck). I imagine bedding them will make them hold up just fine. If they don’t I’ve still got the leupold base I can chop or grab the leupold.

I actually meant to type velocity there. My short prc was an absolute hammer, but at 18” had to be run HARD to get anywhere even close to 2700 with a 140. I just don’t want to experience that again.
I like Warne bases myself, I use them on a few rifles paired with the simple Leupold Backcountry pic rings and that setup works well.

If velocity is paramount, I think a 6.5 SAUM makes a lot of sense for you. I may have some dies still kicking around that you can take if you go that route…
 
I like Warne bases myself, I use them on a few rifles paired with the simple Leupold Backcountry pic rings and that setup works well.

If velocity is paramount, I think a 6.5 SAUM makes a lot of sense for you. I may have some dies still kicking around that you can take if you go that route…
Definitely the way I’m leaning currently. Adg brass, easy enough to find dies, 140 EH/156EOL or 147 eldm. And a handful of guys have done them on the 8400, so I know it will actually feed properly
 
Following this thread, as I have a Kimber Montana and Kimber Classic Select, both in 300 wsm. Considering either chopping one of the barrels to 18" or rebarreling to 6.5prc. Figure I might just drop a little money to chop a barrel, and see how much I like the short barreled 300wsm.
 
Following this thread, as I have a Kimber Montana and Kimber Classic Select, both in 300 wsm. Considering either chopping one of the barrels to 18" or rebarreling to 6.5prc. Figure I might just drop a little money to chop a barrel, and see how much I like the short barreled 300wsm.
I thought about doing the same, it kind of depends how it shoots first. Granted I’m not sure I’m the shooter to print sub moa with a light wsm on day one. 22s and 6s have spoiled me
 
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