Accuracy help, factory Kimber Montana 300wsm

Roninco said:

A friend bought a Montana in 270 Winchester that would shoot two inch plus groups. I bedded the action from the recoil lug to the tang. Afterwards he reported the groups at one half inch.

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Would you mind describing your bedding job?

Might also put it in a Boyd's stock

I had same rifle, same caliber, from 2005 manufacture.
I never had a "flyer" problem as you described but that gun was a 1.5+ moa gun. I ran untold numbers of different factory loads and reloads trying to find the right mix and never discovered a solution.
Without flyers, I chalked it up to that whippy-light barrel.
Really nice carrying it on hunts, not so nice at the range where I only want "interesting" guns.

OG-danimal said:

Would you mind describing your bedding job?

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There are plenty of youtube videos showing how to do it. Brownells Acraglass is a good compound. Be sure to use a releasing agent on all metal parts.

My wood stock kimber had a very nice factory bedding job. I like to do the easiest thing first.

1) confirm it is free floated. free floating is not a dollar bill - free floating is about 3 dollar bills of thickness.

2) If free floating doesn't fix it, now insert 1 or 2 business card about an inch back from the muzzle to simulate a pressure pad. Pressure pads are quite effective.


3) Try "barrel whacking" - see this thread https://forums.accuratereloading.com/eve/forums/a/tpc/f/3221043/m/1111035152/p/1
this is not a joke, it works and won't hurt the rifle.

I have one in 300 WSM, it right at 1 MOA in factory configuration. I wanted a more compact package and cut the barrel to 20" and put self timer SRS TI PRO Tiny titanium brake on it. The same loads that were 1 MOA or better with now all shot 2.5 MOA. I ended up playing with the self timer brake and rotated it 180 degrees and locked it down, I tried some Norma 180 bondstrike and they went into multiple sub .5 moa 3 shot groups, I had a handload with 185 bergers that shot even better. Those tiny barrels are "whippy" dont be afraid to try one of those rubber "donuts you slide up or down the barrel. action torque specs need to be spot on also, I have read about the binding mag box alot also.

I have the same gun and it had the same issues. I had the lightweight, whippy barrel replaced with a heavier contour (3b) 22" Bartlein barrel (making it a heavier gun). Also, had the gunsmith bed the action, free float the barrel and check to ensure the action screws weren't bottoming out. With high quality reloads and me doing my part I can now get 1/2 to 3/4 MOA fairly consistently. I put a lot more money than planned into the project, but it fixed the accuracy problems. (That's the same gun in my avatar.)

MtnTrax said:

Open the bolt make sure you can move the box with finger, it not lightly sand the inside until it's not binding

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I believe that on many rifles the metal magazine box should not interfere with proper torque of the action screws. I have three Weatherby Mk V' and on one the factory decided to add thin spacers between the floor plate and the pillars presumably to give more clearance for the mag box. The spacers might be an interim measure to explore before altering the mag box.

This will help you out. Start at the beginning and follow it through.

I had an early Kimber Montana in 270WSM and had the same issue with poor accuracy! I eventually re-bedded the rifle -- twice before I started to see results! After the 1st re-bedding job I felt I could have done a better job -- so I did it again being much more careful! I made sure none of the trigger assembly was touching as well as the magazine well and it only touched where the screws came through tang, the front action screw and 2 inches in front of the action! I also made sure the action screws weren't too long and weren't touching the sides of the holes! I made sure the recoil lug didn't touch on the bottom of the lug or the front or sides of the lug! I also tried as much as I could to approximate pillar bedding using the Brownells Acraglas! Then I read reports that the early ones had a reputation for poor accuracy! I once met a gunsmith while hunting and I talked to him about blueprinting the rifle and he told me Kimber had the barrel glued into the action and they were very difficult to remove in order to blueprint them and some gunsmiths wouldn't even take on the job! Anyway, after a LOT of load work and after the 2nd re-bedding job and using every bullet weight possible and about 6 or 7 different powders, I finally found 2 very accurate bullets using one powder and 2 bullet weights! Those were Barnes 110gr TSX Tipped and 150 gr Sierra Gameking SPBT bullets and both shot consistently into slightly over 1/4 inch (110 Barnes) to 3/4 inch (150 Sierra) at 100 yards but while only while using H-1000 powder!

Crockett12 said:

I had an early Kimber Montana in 270WSM

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That's what I had….
Didn't bother trying to address the flimsy stock, knew it was good enough for 2 shots while hunting and was no target rifle.
A buddy from my club liked it more than I did, so he bought it, he knows it's limitations.

Cheers.

MagnumManiac said:

That's what I had….
Didn't bother trying to address the flimsy stock, knew it was good enough for 2 shots while hunting and was no target rifle.
A buddy from my club liked it more than I did, so he bought it, he knows it's limitations.

Cheers.

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I actually loved the rifle -- liked the way to felt when bring it up -- liked the way it looked and especially liked the action, which was similar to the old Win M-70 -- but I never felt it was a flimsy stock! I felt it was because Kimber had glued the barrel into the action! Once I got it well bedded, it gave me less than 1/2 inch groups with the 110 Barnes bullet but just didn't like any other bullet, other than the Sierra 150 gr!

Interesting... I have 1980s-era Kimbers (84s in .223 and .17 Mach 4), and early 2000s era 84M Classics (.243, .308, both unfired and NIB). The 80s era rifles shoot 1/2 MOA with factory ammo (Fed Premium 52gr .223, Nosler 25gr BT in Fireball... yes, I checked the chamber). I have shot other early 2000s 84Ms in .243 and .308 and they shot well. I have heard that Kimber quality took a beating over the past decade... is that what it is? Every Kimber rifle and handgun (1911 clones) I fired shot reliably and well, and maybe a couple of customers had minor handgun issues that we corrected at the shop.

They were beautiful rifles but for the larger, more powerful calibers I preferred the New Haven M70 Classics. Not a big fan of light, heavy-recoiling rifles.