So I've got this ancient Marlin 30-30 I put a new scope on. Dialed in took 6 shoots hitting bullseye in center then each corner. Took it out a few weeks ago to do some hog control and missed 4 times in a row. Using same ammo out of same box. Appears to be several inches high. Everything appears right and tight still. Any reason I'm just not thinking of to make it all of a sudden be that far off?

Could be scope? I have an old 30-30 with a Tasco scope. It will drill a 1" bullseye at 100 yards once dialed in but after it sets in the safe a year or so it hits far off to the right before I dial it back. Been hesitant to mess with it because it belonged to my grandfather and I;d like to leave it the same as I got it.

I did buy the scope used but from a reputable person on here. I wouldn't rule that out but don't think he would have sold it if there was an issue with it. Still bugs me that it was 100% dialed in then miss 4 times. I may just pull it completly apart and start with new base rings and scope.

Crappy base and rings?

If it's only "several inches high" how did you miss on the pigs?? My guess is barrel heated up during dial in of scope. Let barrel cool between shots. Now you will be O.K.

Same base and rings it's had on it since day one sometime back in the early 70's

Think I may just go grab new everything and start there. Just hoping it's not something else but can't think of anything else it could be

I quit putting scopes on my Marlins. Now I just use Williams peeps sights and besides being accurate, the gun handles like a lever gun was designed to. - LOTS better than any lever-gun with a scope stuck on top of it.

If I want to use a scope for precision shooting at long range, I use a bolt gun for that.


Williams peep for 336 at Amazon

I read a book once where the sighter tapped the adjustment screws to 'settle' the reticle, then fired another shot to make sure it was still on. It might be that after you adjusted it shifted during transport? Also, try a cold bore shot as mentioned above.

What Young Bucks said was SOP back in the day, when all scopes used a slide tension adjustment for elevation and windage knobs.
Early Leo Vari X II's was the last of the Leo scopes I think that used this system, except it can still be found nowdays on Leo Rifleman scopes last time I looked at one long time ago when they 1st came out.

FWIW the slide tension system worked OK - just not as good as the more current positive click system - just gotta be aware of it and respond as needed. I kept a long handled screw driver in my kit with a wooden handle, instead of a plastic one, so as not to dent the adjustment turret thin aluminum dust caps.
Ron

Did you clean / oil barrel inbetween ?

I had a very nice scope once that would shoot lights out 6 shots of so then be way off until I re zero. Turns out the reticle was loose in the tube and the recoil was keeping it up in place. As soon as you laid the rifle down or transported it...reticle would drop and be way off.

If I was accurate with open sights I would go that way but nothing beats a scope in low light. And I rarely clean rifles usually once a year if that.

Well- just some basic stuff...A heavier bullet hits higher at moderate ranges but you said same ammo. Scopes not tightened down can slide back but you said scope is tight. On a less expensive scope my personal opinion is to always buy a fixed, either 4x or a "pronghorn" 2 1/2x. I've never had any kind of dependability on cheap variable scopes- but maybe that's just me.
You didn't talk about the range you sighted in and the range you shot the hogs. The scope is mounted a couple of inches above the bore. The line of the bore must therefore is slanted up. Theoretically the bullet shoots at this slight upward angle and is on target around 25 yards. On a 30-30 with a fair amount of trajectory, it could be several inches high at 50 to 60 yards and ten start dropping and be on target at 100 yards.

Sighted in at 80 yard(east Texas hunting) shots where about 95-100