A Serious note on "drop in" and replacement stocks/Bedding

K

Kirk Ethridge

New member
Sorry it's been quite a while since i've posted,(5 knee surgeries over the last 8 yrs or so and a broken ankle surgery back in August halted my rifle work. ) , but I've recently been doing some rifle smithing again and found out something quite important. I had sold a couple old Hunter benchrest stock blanks to a friend and have bedded the first one for him.. Jim had given me a Remington 700 short action with a LV barrel and factory lug on it to use as for bedding the stock, so he could keep shooting the actual rifle he wanted to use on the newly prepped stock i had finished for him.. This was a pillar bedding job which turned out perfect as far as myself and he was concerned. (with the action he had provided). It turns out when we tried 2 other barreled actions in this new stock, neither would fit... ie they would not "drop in" ready to shoot as i presumed they should have, (had the actions turned out to be identical to the one i used for the actual bedding job.. The guard screw holes would not line up with the prepared pillars at all. I took the barrel and lug off of the rifle he was going to install and it actually measured .057 shorter than the one i had used for bedding his new stock hence the lug surface contact area in the stock was too far forward.. another friend had a rem 700 short action with LV barrel i had built, (he had it in one of those Aluminum stocks Sinclair sold as "F" class stock several years ago, so was really easy to remove)... This particular barrelled action fit absolutely perfect with full lug contact. So far 2 of the 4 actions tried fit the newly bedded stock correctly..

This got me thinking of a "drop in" stock i had used on an Alpine action (700 short action footprint) 7mm-08 deer rifle for one of my grandsons.. I had never really got this rifle to shoot as small of groups as i wished. A previous 7mm-08 i had built and "dropped in" the exact same brand/style of stock shot tight as any rifle with a sporter barrel has a right to,,, I had shot 5 x targets on a 200 yd IBS score targets
off a bipod no less with this rifle that i built for a friend. Checking it, it had full lug contact in the "drop in aluminum block chassis stock". I just checked my grandsons beautiful alpine actioned 7mm-08 and there is at least 1/16 inch or more of space between the lug and stock bedding block!.. I'm adding bedding to it soon as i finish typing this. I'm expecting this should make load development a little easier, and bring group size down. If it don't, proper torque free bedding is not as important as i feel it is! All my previous rifle builds were bedded with the action to be used in the stock, so this little "serious problem" had never came up in my builds.

The deal is, I had never bedded a stock before that may have been intended for use with multiple barreled actions.. It really surprised me of the variation in length/guard screw spacing ect.

The lesson learned from this is to make sure you have full recoil lug contact with any "drop in" stock you choose to use. They obviously have to make the lug mating surface a little short in order to accomodate these variations in action length, otherwise a good number of "drop in" barrelled actions wouldn't "drop in" these stocks. Obviously, these well built fine "replacement" stocks sometimes need a little extra attention/love to get the max accuracy out of your rig.

Hope this helps someone..

Kirk
 
I can't imagine why the screw spacing would vary, but I have read of this last week on a different forum. Would the actions be different enough in length from truing the action face to make some not fit?
 
I've always taken "drop in" to mean that all the tolerances are sloppy enough that most factory guns will "drop in." That in fact NOTHING, including the recoil lug bearing surface is anything but "relieved to be out of the way."

Factory guns vary, a lot. Action hold down screw hole spacing is just one of many variables.

I don't mean this in a disparaging way, it just IS what it is. I assume all dimensions to vary between actions. Even custom actions (altho some of them are close, close enough that parts may be "safely interchanged" at least)
 
stock

i've not used but 2 "drop in" stocks that i can remember.. The first one worked perfectly with grouping absolutely great on this sporter deer rifle, The 2nd one i used (same brand & design) fit very poorly, & required a complete bedding job even though it was the same make and model of a "drop in". the "chassis" design was different looking however, i suppose because the stocks were bought several years apart. These 2 stocks were installed on excellent custom actions with the rem 700 footprint. (they were different make/model actions either of which i would use again) however.

Incidentally, the screw hole spacing was identical on all of the 4 rem 700 actions i tried in the stock i bedded (not a "drop in") . 2 wouldn't fit & this was because of the action length. with the recoil lug in contact with the stock bedding, the action guard screw holes were either too far forward or rearward to line up without an excessively large pillar hole..

These "drop in" stocks are marketed primarily to the "non" gunsmith as an upgrade to factory stocks. It is obvious from my experience that it would be either a hit or miss situation as to whether or not improvement in grouping would occur... Also, this same variation could explain in part why factory rifles of the same make/model/caliber do not perform equally. The factory stocks have to be built sloppy enough to compensate for this. I'm pretty sure the injection molded factory stocks are also "drop ins" so to speak.

regarding the action face, none of these were "blue-printed" actions. so squaring of the action face had could not have been an issue. (I was just doing the stock bedding for the guy when i found this issue)

Kirk
 
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