Extra Cavity in Buttstock

[The Rattler]

I am refurbishing the gunstocks of an old Wingmaster. After removing the buttplate, there are 2 holes bored in the rear: One goes from one end to the other and is for the rod that attaches the buttstock to the receiver; the second is only around 3 or so inches deep, and has nothing in it. At least that was the case when I recently bought the gun.

What is the purpose of this empty hole bored into the wood?

Would it be in any way detrimental to apply 0ne thin coat of a sealer into about 1 to 3/4 inch in these holes that are on the rear end of the buttstock; i.e., not to the front of the buttstock where tolerances are tighter?

Thanks.

[Banshee]

To add weight i would assume. I have a 3/4 carbide blank in the stock of my TC Trap.

[Synchronizor]

You'll see two holes in the butts of 870 stocks in early pictures or illustrations, so the extra hole was probably standard at one point. My guess is the same as Banshee's, it's probably there so you can add weight to reduce recoil for things like trap shooting or waterfowling (free recoil energy is inversely proportional to the gun's total mass). You didn't mention the hole's exact diameter, but a 1" wide by 3" deep cylindrical space could hold almost a pound of lead, for example. Early on, 870s also came with a special weighted plug that you could use to add 3/4 of a pound to the magazine tube. It was a nice accessory for your 870's duck mode that you could remove when you took it upland hunting.

These days, I feel like the industry (probably following their customers, to be fair) has stopped caring about properly matching a gun's weight to the recoil of the shells being used in it. Every shotgun is meant to be a "do-everything" model, even if it's a pig in some applications and/or a shoulder-destroyer in others. At least with the 870, there are all kinds of accessories and modifications you can do to suit it to different loads.

[The Rattler]

Many thanks for these replies?