There was another thread about bedding the Kimber Montana, and another with "accurizing" ideas. I'm one that thinks there is more than one way to achieve a goal, and rather than post on those good threads, I thought I'd just put up my own comprehensive post, sharing my own experience, methods, and observations.
As to history, I got my first Montana (8400 300 WSM) in the Spring of 2004, and have had something like 16 in the intervening years. Four were 8400's, and the balance in 84M and L's. Everything I'll share here I've done to all those, and I've never had a Montana that wouldn't shoot something sub moa.
Here's my rifle Pre-flight Checklist
, some of which is specific to the Kimber, but most of which I apply to any new rifle:
1). Bed full Receiver and Shank (or full chamber).
2). De-grease Bolt and Trigger (Brake Cleaner).
3). Re-Oil/Grease Bolt and Trigger.
4). Apply nail polish to firing pin set screw (Kimber).
5). Adjust Trigger to 2.5 - 3lbs (MT's I like 2.5lbs).
6). Break top of feedramp with fine rattail file.
7). Polish feedramp and underside rails with 600 Emery.
8). Eezox all metal below stock level.
9). JB Weld scope ring bases to receiver top.
10). JB Weld sling swivel studs to stock.
11). Lap Rings, and de-burr with fine rattail file afterwards.
12). Mount scope in rubber cement. Blue Loktite ring screws.a). With the 84's, make sure to check that the forward receiver scope base screw does not bottom-out into barrel shank. This is not always the case, as it was not with the rifle in these photos.
b). Much has been made about the mag box bottoming-out in the stock. I've never had this problem, but it certainly bears paying attention to.
c). Torque Specs: Front action screw, 45 inch lbs. Rear action screw, 35 inch lbs. Scope bases, 25 inch lbs. Ring screws, 20 inch lbs.Bedding:
First some general thoughts... I've read the idea of bedding the MT with only the rear action screw tightened and a "guide screw" in the front. Have also seen "finger tightening" the action screws only. My own view is the action should bear on the pillars. That's what they're there for. Without using a bit more pressure than the above methods provide, the action isn't going to bear on them tightly, while oozing out excess epoxy. I put my action screws in "farmer tight" while bedding in order to make full pillar contact, and to move out excess epoxy. Afterwards I employ a torque screwdriver for consistency. As I said originally, there is always more than one way to do something, but I prefer my own method obviously!
Though the Montana is factory bedded with a "slave" action, it's surprising how much area will fill up with epoxy while still making full contact with the pillars. The factory bedding, however, really does move the process forward a fair bit, but I really don't think there's any substitute for bedding the actual action to the actual stock.
Bedding an already painted rifle is a bit more demanding than bedding a stock blank with no paint. More care is required to avoid beating-up the paint. Just a head's up.Bedding Stuff:Epoxy
- I like Acraglass Gel or a similar Gel like Marinetex. I've also used runny 2-part epoxies but have always added a thickener like Cabosil (fumed silica) to those. The important thing is to NOT use non-thickened epoxy. I see guys using JB Weld, and while anyone is free to do what they want and it undoubtedly works well enough, I prefer a stronger epoxy. I use JB's on less critical chores like ring bases, where I prefer a weaker epoxy.Release Agents
- A lot of different ones work. I use Paste Wax for some aspects of the job, paint-on Brownells blue release agent for others, and Brownell's Acra-Release Aerosol for the barreled-action. Exacto Razor Knife. (I prefer a no. 2 blade - have extra's on hand).
Blue Tape or quality masking tape (I prefer masking tape).
60 Grit Sandpaper.
Fine artists brush (think small sable).
Before I take the action apart from the stock I take the Exacto knife and score the paint around the tang to give my self a "guideline" to prep to. I also mark the stock with a pencil where I want the bedding to stop at the barrel shank.
After disassembling and setting the barreled action aside, I begin by prepping the stock.
I score a line in the stock at the end of the shank where I want to stop the epoxy. I then sand all the areas I want to bed with 60 grit, including down inside the lug area. Where I want to be careful to not over-sand into finished paint (like the tang and forward the shank) I score and "crosshatch" with the exacto, essentially duplicating the sanding, but in a more controlled way. After all this is done I wipe all the sanded areas down with acetone until all residue is removed.
Next I apply blue tape or masking tape along the top of the receiver, letting it overhang into the stock (PS, I prefer quality masking tape to blue tape). I then take the exacto and cut off the overhanging tape. It's important when using tape to really press it down to mate to the stock.
I then coat (the artist's brush) with the Brownell's blue paint-on release agent any and everywhere I DON'T want epoxy to stick. Those areas would include; Inside the pillars, the taped areas, inside the mag well (3/4 - 1" below the area being bedded), the barrel channel forward the shank where I want the epoxy to stop (put a lot here forward the shank - the epoxy will ooze forward!), the tang, the bolt handle cutout, etc. You really don't necessarily need tape on the stock... two coats of the blue release agent thinly applied will work on the stock, but I usually put tape on the flat surfaces for trimming purposes:
You can really see the blue release agent in this photo all around the tang and on the inside of the stock:
Next, I de-grease with acetone all the rifle surfaces to be be bedded. With the Montana I don't remove the trigger, bolt stop, or anything (other rifles I sometimes do). I wrap the trigger with tape and fill any voids with modeling clay. I fill the tang and lug screw holes with paste wax, and also the gas port. I re-wipe those areas with Acetone, and spray the entire receiver with the Brownells release agent, then set it aside:
I coat the action screws with paste wax so they'll release later: