My Kimber Montana Tinkering

Marbles

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This thread started with one idea, and has morphed into a stream of consciousness style narrative. Hopefully the information in it can help some with their own tinkering, and as mistakes are many times more valuable for learning than success, I have tried not to hide mine (other than avoiding photographs that show the flaws in my spray paint job :eek:). It should also be obvious that the input of others has helped me in this project quite a bit.
End edit.

So, I will start by saying that this is only one example and an n of one is a dangerous thing to draw conclusions on, however when combined with other data it can be informative. It sounds like I had worse luck than most who get a new Kimber.

I changed out my Sako model 85 in 30-06 for a Kimber Montana in 30-06 in the spring. At first I thought everything was great with the Kimber, slowly I have concluded that is not the case. That said, I see no alternative that I like more, so I will stick with it, even if it becomes nothing more than a donor action. I like CRF (Sako is pseudo-CRF) and three position safeties, no other platform I can find offers that at this weight or price point. Part of the reason for switching was also the desire to tinker and customize. So, I'm not unhappy with the Kimber, but I'm also not impressed with the QC.

The Kimber is of new manufacture.
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These were on the inside of the stock in the mag box. The gun came new from Eurooptic, still in the factory plastic bag.

The Kimber action is not nearly as smooth as the Sako, though it is on par with FN manufacture Winchester model 70's I have handled, it may even be a little better, I just don't have the time behind a model 70 to say with confidence. A Tikka action feels smoother to me.

Like I said, on initial inspection I thought all was good. After putting 20 rounds through her at the range I found several issues. The mag box was binding, 45 seconds with a file fixed this. The front action screw was too long by a hair.

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The shiny spot was not their before firing and shows where it was bottoming out. About a minute with a file corrected this.

The factory bedding job is practically non-existent.
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In the above images you can see where paint and metal clearly have contact on the bedding posts with wear isolated to these areas. When I get time I will bed it.

While not visible, a slight smoothing of the finish can be felt in the action area and forward of the recoil lug to the barrel tapper indicating there is some contact at these points. The barrel is free floated beyond this.

Before anyone brings up torque, I use a torque wrench and set the action screws at 45 in.lb.

Accuracy is good enough for hunting, and my shooting is not good enough for me to swear it is the gun. I will say, I got better groups with the Sako. So far I have put 280 rounds through her.

The firing pin spring needs to be replaced. I had two FTF using cheap Remington ammunition at the range. Neither would fire on a second try, so I assumed it was an ammunition issue. However, on a recent hunt I had an FTF using premium Winchester ammunition. This round also did not go off on a second strike. Thankfully this did not result in the loss of an opportunity and there is just a live round somewhere in the muskeg.
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Two days earlier we had a close encounter with a curious black bear, less than 20 feet away and did not run off until I closed that distance to under 15 feet. My partners gun was strapped to his pack, so the Kimber was the only weapon available for protection if the bear had been aggressive. So this failure could have had worse outcomes than just a lost animal. I should have known better than to ignore it on the range, however I wanted to assume the best about the rifle.

She took a beating on that hunt, and other than scratched paint and rust on the mag box and scope ring screws she held up very well.
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My modifications so far have been an oversized Ti bolt handle as the objective bell of the scope was close enough to slow me down with the regular bolt handle. You can also see where I removed a portion of the picatinny rail to allow better access for loading the blind magazine. I know Tallies would be lighter, but the picatinny rail allows me to move an expensive scope to other guns. I also believe it is a more robust system, though this is debatable.

I cut 4 inches off the barrel. It was 24.5 inches from the factory measured from breach face to crown, so it is now 20.5 inches. Accuracy improved slightly after the cut and crown. The cut took all of 5 minutes, the crown took about 3 hours as I lacked the proper tools and used a 1 inch steel ball bearing with lapping compound to finish it.
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After bedding her, I plan to use the left over Devcon with some microballoons and a layer of fiber glass cloth to build up the comb so I can ditch the stock pack and duck tape currently serving that purpose (8.8 oz).
 

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Marbles

Marbles

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As she sat for that hunt, unloaded weight was 7 lbs 0.5 oz. Not bad for a scope and ring set up that comes in at over 22 oz.
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1 oz
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3 oz
 
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I owned an Adirondack that had those issues. I replaced the firing spring with one from Kimber. The new one was significantly longer than what came out of the bolt. However I also had FTF's as well on numerous occasions. I thought that the spring would rectify this. It didn't. I sent it off to the gunsmith I use in Fairbanks where he found that the rifle had a headspace issue. Rifle was re barreled. I would take yours to a competent gunsmith and have the headspace measured. I know that mine failed in a couple critical situations, thankfully only on game and not involving a bear.
 
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I owned an Adirondack that had those issues. I replaced the firing spring with one from Kimber. The new one was significantly longer than what came out of the bolt. However I also had FTF's as well on numerous occasions. I thought that the spring would rectify this. It didn't. I sent it off to the gunsmith I use in Fairbanks where he found that the rifle had a headspace issue. Rifle was re barreled. I would take yours to a competent gunsmith and have the headspace measured. I know that mine failed in a couple critical situations, thankfully only on game and not involving a bear.

Good to know. A trip to the gun smith is now on my list.
 

Wapiti1

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A couple of other things to check on a FTF.

Have you taken the bolt apart and cleaned the interior? A new spring may be needed, but it may also be full of shavings from machining. I've seen that on factory rifles from several "trusted" manufacturers.

Also check the firing pin protrusion from the bolt face. It should be about 0.045"-0.055". Wouldn't be the first short pin or mis-matched cocking piece ever installed.

Jeremy
 
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After I checked my firing pin protrusion of course, I was still get a wide range of primer strikes. Some good, others really light. Also some would be dead center and others off to the side. Too much headspace was causing the round to move within the chamber when fired. I would imagine an issue of just a weak pin would cause only light strikes and not the wide range that I was seeing. Something to check.


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A couple of other things to check on a FTF.

Have you taken the bolt apart and cleaned the interior? A new spring may be needed, but it may also be full of shavings from machining. I've seen that on factory rifles from several "trusted" manufacturers.

Also check the firing pin protrusion from the bolt face. It should be about 0.045"-0.055". Wouldn't be the first short pin or mis-matched cocking piece ever installed.

Jeremy

Thanks.
Inside of the bolt is clean and was clean from the factory. Firing pin protrusion is certainly over 0.045. Cannot say exactly as I don't have the correct tools, but it is a good bit longer than a 0.035 feeler gauge and shorter than 0.067, but closer to 0.067 than 0.035.

The primer strikes at the range looked to be solid, I did not ever put eyes on the primer in the field. The primer strikes on spent brass are all consistent. The primers are not overly flat, though some protrude ever so slightly beyond the rim. On inspecting the brass, there is clear signs of case head separation. (Edit, this is wrong, which is discussed further down). 20200902_113737.jpg
You can see the stretched brass on well on the case 3rd from the left in the picture, I can feel it on every piece of brass. I compared the nickle plated brass to the un-fired factory rounds and the case/head junction is both visually and palpably different.

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Primers.

Looks like I will need to throw out the brass. Guess a trip to the smith is due sooner rather than latter. If it is out of spec, I guess I will consider sending the gun back to Kimber before I modify anything else (I hear they like to return them to factory condition at the owners expense). Swap the bolt handle back, and confirm they will not give me grief over the shortened barrel.

Reynolds and Wapiti, thank you both, I've learned more than I expected today.
 
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Wapiti1

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That isn't head separation. That is a loose chamber, which is normal on factory rifles. They order reamers that are cut several thousandths over the min chamber dimensions so they can get more life out of them. They are in spec, but fatter than a "match" reamer. It is also possible they had a little wobble when reaming and cut it fat due to that.

Separation would be from excess headspace, and would show as a bright ring or partial ring at the web where that slight bulge is on your cases.

The firing pin indent in the bottom photo looks a little shallow to me on all but the two cases to the left.

Changing the spring is in order.

Jeremy
 
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Marbles
Those things are pretty typical of Kimbers and other rifles also. Also be sure to check your front scope base screw for contact with barrel threads.
 
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That isn't head separation. That is a loose chamber, which is normal on factory rifles. They order reamers that are cut several thousandths over the min chamber dimensions so they can get more life out of them. They are in spec, but fatter than a "match" reamer. It is also possible they had a little wobble when reaming and cut it fat due to that.

Separation would be from excess headspace, and would show as a bright ring or partial ring at the web where that slight bulge is on your cases.

Thanks for the feed back, I would say you are correct. I cut down a spent case and cannot see any thinning inside.
20200902_135239.jpg
Arrow points to the bulge point, which starts once the support from the head is lost.

New Wolff extra power spring was ordered a few days ago.

Marbles
Those things are pretty typical of Kimbers and other rifles also. Also be sure to check your front scope base screw for contact with barrel threads.

Thank you. Front scope base screw has about 1.5 threads worth of clearance from the barrel.
 

Wapiti1

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If you have a neck sizer, you'll get good brass life in that rifle. If you full length size, it will be about 4-5 reloads before it really will separate. Assuming you reload.

Good to know Wolff makes a spring for that rifle.

Jeremy
 
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If you have a neck sizer, you'll get good brass life in that rifle. If you full length size, it will be about 4-5 reloads before it really will separate. Assuming you reload.

Good to know Wolff makes a spring for that rifle.

Jeremy

Don't to reload yet, but saving brass as I plan on doing so. So good to know about neck sizing instead of full length.
 
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Seems like you have pretty much covered all the normal Kimber woes.
Here is a great write up for anyone else looking for tips.
 
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I meant to add, even though the Kimber is lighter than the Sako by about a pound, I find the recoil less punishing. I attribute this to stock design along with better fitment. I have put 100 rounds through her in one range session and had no issues with soreness.

As for the Nightforce, I find optical performance drops off above about 6x and in low light (though if I can see it with the naked eye I can shoot it with the NX8). I was aware of both of these before purchase. They are the trade offs for lighter, compact package; and 1x. I can resolve bullet holes in paper at 100 yards on 8x, so clearly it is not terrible; but it is noticeable in comparison to its performance below 6x. Low light performance is judged against Zeiss Conquest 8x42 binoculars. I have not owned any other decent glass to compare it to. It is hands down better than the Weaver K4 it replaced in every respect other than weight.
 

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I bought one of these in WSM for a Father’s Day gift project. I ended up getting one load to match both our rifles, but the chamber was def larger on the Kimber. The same loads in my rifle would close stiff, in his rifle was loose as could be. Shoots fine, after a duracoat and dip, he loves it.

It also had a weak spring and when the safety was in the unload position, you could depress the trigger. There was a bit of wear in the safety, so had that replaced as well. It was used, but I’ve never had to do all that to a used gun before.
 
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We will see if I got this right tomorrow.

Prepared stock. I sanded all the paint off the contact areas, and scrapped it off the recoil lug recess. Then took my wife's dremel and one of her jewelers burrs to rough up the finish. There where some large air bubbles in the stock, so I also opened them up enough that epoxy could fill the void. I found a couple places where these bubbles had been filled with a very soft white material at the factory, so I removed that too. Then washed the whole thing with alcohol. As can be seen, I decided not to bed forward of the recoil lug.
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Action prep. After going to three different stores I was unable to find neutral shoe polish, so I oiled the action well. Packed it with sculpey clay. Then sprayed the whole think with Silicon PB blaster and let it drip dry (guess if this does not work I will be taking a torch to it). I taped the forward and bottom sides of the recoil lug. As the lug is tapered, I decided not to tape the port and starboard sides to provide a tighter fit and, in theory at least, allow it to resist rotational forces better. We will see if I regret that.... I also picked up some Forster Stock Inletting Guide Screws for a Remington 700 from Midway USA as Remington's use the same 1/4-28 TPI threads.
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Used Electrical tap around the barrel to keep it floated, and when I dropped it in the stock I taped over the spot that was wrapped to hold it in the stock. I also taped the tang down. I had to build a small electrical tape shim that is between where the trigger would be and the rear action screw as once the factory paint was removed the action sat about 1/10 of an inch too low in the stock.
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I used Devcon Titanium because I had already bought it. If I had not already had the titanium I would have used Devcon Aluminum or Marine Tex Grey. When I bought the Devcon Titanium I did not realize it only had a 20 minute pot life. I dropped the action in at about the 18 minute mark after mixing and could tell the putty was getting thicker and harder to work.

13.5 hours to go until I get to find out how I did.
 
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