Shifting point of impact

[Wally Whitetail]

Hi all. I'm new here. I'm from MN. Just started hunting deer last year and bought my first centerfire rifle about 6 months ago. It's a Winchester M70 Featherweight with a stainless barrel chambered in .308. I did a bedding job on it by following a guide by GunBlue490 on youtube because I was getting decent groups with several types of ammo, but not great (nothing sub MOA). The bedding job went well as far as I could tell. I work with epoxies professionally, so I felt confident that I could do the work in a competent manner, and the results look great.

My issue now, though, is that I'm experiencing strange groups at the range, where I'll put two shots very close together and the third will be 2-3 inches away. I have several groups where that "flyer" is in the same direction about the same distance, but sometimes it goes back and forth, 2 here and 2 there, but there is a definite disconnect between what I'm seeing in the scope and what I'm seeing on the target. I'm a lifelong shooter and I have pretty solid trigger control, and I've shot enough with this setup to confidently say there is a pattern here that exists independently of my human error. Now the other relevant bit of info is that I'm shooting primarily solid copper bullets. The ammo that I'm seeing these groups with is Barnes VOR-TX 150g TTSX. I've shot a lot of this, as well as the 130g ammo of the same variety.

My question is this: should I suspect my bedding job is the culprit, or is it more likely to be copper fouling that I need to use a copper solvent on? Until now I've only used standard mineral spirit based cleaners like no.9 (as per the advice of GunBlue490 again, who claims solvents are a bad idea and that the copper only smooths the bore and doesn't require solvent removal).

Thanks for your input. Let me know if I've left out any necessary info.


WW

 

[Steel head]

You could possibly bed it.
I”d bet that it’s more you than the rifle.
It’s a common problem especially with light rifles.

<<<<<From Lake of the Woods county.

 

[steve123]

Your photos aren't coming in for me but if you bedded down the barrel channel on the stock also, that would cause a major POI shift. Don't bed the actions screw holes either.

A hunting rifle is usually a 1 shot deal, maybe 2 shots. I tell my buds to leave their barrels fouled at least with a few rounds. In our area it's a 5 minute drive to take a cold bore shot which is the most important shot and often a little off from the others in a light barreled hunting rifle.

 

[Newbie2020]

Check torque on all screws: action screws, scope mount screws, and scope ring screws. Embarrassed to admit I had this happen once only to find out stuff wasn’t tight.

 

[roggom]

You can try waiting 2 min in between shots, but from the sounds of it, your rifle does not like that ammo. The flyer may be you, but just not a node that works well with your rifle. One simple thing to also try, is to pressure bed the tip of the forestock. You can do this with some cork gasket material from autozone. if it works them you can cent the cork in or epoxy a pressure point with about 5-10 lbs of pressure. https://yarchive.net/gun/rifle/bedding_pad.html

 

[spife7980]

Could be all of those

Sounds like a factory feather weight barrel to me.
Sounds like a bad bedding job to me.
Sounds like shooter error to me. Sound like loose scope rings to me.

Are you shooting them rapidly back to back? What happens if you wait 10 minutes between shots?

 

[Wally Whitetail]

I'm waiting a minute or two between shots and checking the barrel temp as I go. As far as the bedding, what's in there now looks much like the factory bedding job, minus the large air bubbles in the resin that were present from Winchester's job. My resin did not go into the barrel channel except only slightly beyond the recoil lug, just like they had done at the factory. I followed GunBlue's advice on the action screws; that is to say I let the epoxy enter those screw holes around the lugs, creating something of a pillar bedding there, but I chased out the rear one with a drill bit to relieve any pressure on the screw there (again, following Winchester and GunBlue's lead on this). One thing I did do that may be an issue is to apply tape to the front face of the recoil lug to allow a small amount of space to get it in and out of the stock easier. GunBlue didn't do this on the Tikka he was working on in his example. I had seen Nathan Foster of Terminal Ballistics Research do this step on his bedding jobs and it seemed like a good idea to me, since the epoxy made a perfect matching surface on the rear of the lug and would be securely held against that by the front action screw, but it could be creating a masking tape-width gap in the recoil lug recess on the stock. Not sure if that could cause my issue, or again, maybe it's copper fouling. I did check the torque on my action screws and that much is fine.

 

[Newbie2020]

I don’t think that’s the issue as long as you feel you’ve got solid purchase of the back side of the recoil lug against the front side of the recoil lug slot.

And that you’re consistently getting two tight POIs and a flyer, says something else is boogered.

I’ve been surprised at the amount of variation there is among manufacturers re: torque specs on scope rings and bases.

 

[MarinePMI]

Have you considered that the scope may have gone bad? I've had an old Vari-X II (many years ago) do the exact same thing you describe. It was unpredictable when it would "throw the flyer" but it was always in the same spot. And then it'd shoot there for a few rounds, and then, boom, it'd shift back to the original zero.

Remember, the scope is always the weakest link on a rifle.

 

[Slab74]

If it’s a hunting rifle and the first two shots are always consistent, don’t worry about it. I have a tikka super light .308 that is factory, that does the same thing. The fluted pencil barrel does not like three shot groups. I stopped load development once I got it down to 1.5”. I was able to drop an animal at 257 yards with it, and it did not care where shot three went. When hunting, 1 shot, cold bore, is the one that counts. If you have to shoot more than once, the adrenaline will have a larger effect than the mechanical accuracy of your rifle.

 

[Campguy308]

The first thing I'd do after verifying everything is tight is try different ammo. Lots of 308 to choose from.

 

[hereinaz]

I dislike Barnes solids and the special considerations they require. They are much harder to get to shoot well than copper jacket bullets. Personally, I would strip the barrel clean with solvents of the copper from those solid bullets. Then, I would see what some Federal Gold Medal Match and Hornady Match or Precision Hunter ammo shot like, get a baseline from a quality load. Strip it because lead core bullets sometimes don't like being shot in a rifle fouled by Barnes copper bullets. I haven't see the videos you speak of, but there are a ton of very good shooters who use solvents. It seems to me that you are learning (just like I am) and you are getting half the information you need ( I know cause I went through the steep learning curve too).

Also, float everything in front of the recoil lug.

 

[Wally Whitetail]

Thanks for the advice all. Looking into your suggestions. I see my target images didnt load in the original post. Here are links to three of them.

https://ibb.co/XLtWCX7
https://ibb.co/mNkXf7w
https://ibb.co/TwmV826

 

[Brux]

Lot of things to consider. Eliminate them one by one.
First that I would look at is a copper fouled barrel. I have had quiet a few rifles brought to me and everybody had the same question [my rifle use to shoot good and now it don't,whats wrong with it?] almost all of those people were shooting Barnes bullets and had a bad cleaning regiment. The barrels were copper fouled to hell. I cleaned and inspected all of them and told them to go shoot 3 fouling shots and shoot it for group. It has worked everytime. Not saying this is your problem but I would clean the shit out of it [all copper] and shoot it. If that doesn't work go to step 2. Good luck