What’s this wear mark?

I wanted to ask brighter bulbs than me about the wear marks that have appeared in the inlet of my McMillan Hunter stock at the rear action screw and recoil lug. It's inletted for a Savage that's chambered in 300 WSM using a factory barrel but an upgraded .250" recoil lug.
I'm assuming these marks mean I'm getting movement when shooting and I'm also assuming bedding it would solve that? I torque the screws at 40-in lb as Savage suggests.
It shoots pretty dang good like it is, for a factory barrel and all—getting consistent groups of .75" or so at 100 yards and it'll usually hold that 3/4 MOA or so out to 600 as long as I do my part.
I've put about 350-400 rounds through it in the 5 years since I put this stock on it. I break it down at least once a year after hunting and give it a good cleaning and I don't recall the action screws ever being loose when I've done that. This isn't the first I've noticed it but like I said, it shoots fairly well so I never really dug in to find out.
Thanks for the help!

Get it bedded

stock bolts loose and as said above get it bedded

It's hard to tell by the pic, but to me it looks like there is a crack to the left of the rear pillar and along the rear edge of the magazine well. That would account for the movement causing the scuff. If in fact it is a crack, I wouldn't shoot it until it was repaired and bedded.

Good bedding and a floating barrel is its own reward.

Those marks are called "Fretting Marks" in some disciplines. Can happen when the fit isn't great, even if the fastening method is to spec. They are a sign of relative movement, so as Victor3 said, bed it or have it bedded.

The pillar has been compromised. What happened there?
There is the cause of your movement. I'm guessing there was a need to cut out part of the pillar for inletting.

Rosebud said:

The pillar has been compromised. What happened there?
There is the cause of your movement. I'm guessing there was a need to cut out part of the pillar for inletting.

Click to expand...

Yeah the pillar is like that because that's a product of how it needed to be inletted to fit the action. It's also one of the reasons McMillan said they stopped inletting for Savage rifles—because they had to remove so much material around that action screw to allow for the sear to function. But they've since gone back to inletting for Savage in a few of their stocks from what I've seen.

I'm thinking the root cause hasn't been correctly identified. My observations: 1) the wear marks (if that is indeed correct) are not parallel with the pillars centerline, 2) how could such movement affect one pillar and not the other? I suspect your marks were present before you installed.
The recommendations to bed have merit. McMillan recommends installing with correct guard screw torque and, if your targets satisfy your expectations, the install of your new McMillan is completed.

Rflshootr said:

It's hard to tell by the pic, but to me it looks like there is a crack to the left of the rear pillar and along the rear edge of the magazine well. That would account for the movement causing the scuff. If in fact it is a crack, I wouldn't shoot it until it was repaired and bedded.

Click to expand...

Good catch,it does indeed look like a crack.

That is typical of savage action screws. There is not much meat there at all. The hole is just too close to the inlet.

Rflshootr said:

It's hard to tell by the pic, but to me it looks like there is a crack to the left of the rear pillar and along the rear edge of the magazine well. That would account for the movement causing the scuff. If in fact it is a crack, I wouldn't shoot it until it was repaired and bedded.

Click to expand...

Thanks for calling that out. I took another look at it with a bright flashlight and took another photo and it definitely looks like a crack. I just sent McMillan an email with the photo pointing out the crack.

Jasbo said:

I'm thinking the root cause hasn't been correctly identified. My observations: 1) the wear marks (if that is indeed correct) are not parallel with the pillars centerline, 2) how could such movement affect one pillar and not the other? I suspect your marks were present before you installed.
The recommendations to bed have merit. McMillan recommends installing with correct guard screw torque and, if your targets satisfy your expectations, the install of your new McMillan is completed.

Click to expand...

I special ordered the stock directly from McMillan and those marks definitely weren't there when I got it or I would've sent it back. Not sure how it would affect one pillar and not the other except that the front pillar has better, more uniform contact with the receiver. I always torque the action screws to Savage's specifications with a torque screwdriver.

Fill the cracks and get it bedded.
Unless they will give you a new stock and if they do bed it to your action, problem solved