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Posted: 4/15/2014 3:54:23 PM EDT
[#1]
I have fit a couple of them. They can be a pain. The last one I did had the rear hole for the receiver drilled out of place. I had to drill it oversize to make it fit.
You need clearance around the stock at the tang to prevent recoil from splitting the stock behind the receiver (so make sure you have clearance along the sides and behind the tang where it sits down into the stock). You want firm contact between the stock and receiver underneath the front ring, and under the tang. You want contact between the receiver lug and the recoil bolt in the stock. The purpose of the rear pillar is to prevent you from crushing the wood in the rear of the stock. The CMP stocks come with a bushing made from wrapped sheet brass, toss it and make a proper one from a piece of 1/4" brake line tubing. You want the barrel to be free floated except for the very front, where you want 5 - 7 lbs of upward pressure on the barrel. Matt |
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Posted: 4/17/2014 8:38:46 AM EDT
[#2]
Also be certain that the bolt handle does not contact the stock, or it will affect accuracy and possibly cause other problems as well.
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Posted: 4/20/2014 6:52:17 AM EDT
[#3]
go real slow,
use a good set of wood files to fit the action into the wood, just be careful and dont go crazy. it will be a tedious process. it usually can take me 3-10 hours to get a stock right, just fitting it. when i am working on a stock, i use 80-100 grit to shape the wood, and use finer grit to smooth it out. make sure the wood around the stock where the bolt handle goes into the stock has just enough clearance, but not too much start with the action area first and then work up the stock to the tip of the barrel fitting it as you go. be careful and take your time and dont get distracted |
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Posted: 4/21/2014 3:48:15 PM EDT
[#4]
Anywhere to find dimensions of the proper inletting etc. to know what it should be? thanks for the replies .
Edit to ad how can you check for the 5#s of upward pressure? Is that measured at the bottom clips that cradle the barrel to the lower part of the stock? |
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Posted: 4/21/2014 6:39:46 PM EDT
[#5]
...The information you may have found (photo of stock with red arrows maybe) was mine.
 I have fitted a couple of these this year to my 03A3 and A4 rifles so I don't have to abuse original (and less than optimal) wood. What I have found, more than anything, is that the action rests on the radial surfaces on either side of the trigger clearance hole and holds the action's rear tang bedding surface (where the bolt threads in) up off of the stock. So when you hear people complain about split stocks what you are likely seeing is this issue where the action is pulled down and bedding on these radial surfaces forces the stock apart and it eventually splits under recoil, etc. Use a color transfer medium, lipstick, inletting black, candle soot, to color the bottom of the barrel, the recoil lug, handguard rear retaining ring, and bottom and sides of action. Put it in the stock carefully, draw it together with the bottom metal and bolts. Ideally you want the action to bed on the flat area behind the recoil lug and on the bottom of the rear tang. I generally leave just a bit of contact with the radial surfaces for added stability but really there isn't much pressure. I also find that on some stocks (not the CMP yet) the barrel will contact the barrel channel before it reaches the bedding pad at the end of the stock. You have to clearance for the handguard ring and likely some under the area protruding from the action that holds the cut-off. To reduce the radial areas I use a suitable round object wrapped in sand paper. You will notice that on the front maybe 1/3 of this area you will have hard contact. Look at the bottom of the action and you will see the features causing it. I scallop those areas with a suitable rounded chisel. I also remove wood in the other non desirable contact areas with a chisel or some sandpaper. Once you get things bedded properly in the action area, if you want more for-end pressure, reduce the height of the pad behind the recoil lug. I generally use a scraper and then flatten with a sanding block. A little goes a long way and you need to re-check your bedding in the barrel area for contact. You have roughly a 6:1 ratio here. Assuming rear tang to forward pad is 4" +/- and from that point to bedding point is about 24" +/-. SO for every .010 you go down there you reduce that height by .060 at the barrel tip bedding. That is how you increase upward pressure. These are just guestimates ratios off the top of my head but should be close. To measure upward pressure a fast and dirty way is to clamp the gun in your gun vise and grab your trigger pull gauge. With just the action secured in the stock put the gauge right in front of the stock and lift. I generally hold onto the stock to keep it from lifting. When it begins to separate let go and see what the scale read. Again not exactly scientific but quick and dirty. Hope that gets you started. |
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Posted: 4/22/2014 6:34:08 AM EDT
[#6]
Found some good info on the cmp site forum.
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