Zeroed at 50, off at 100
 

Hi All,

I just bought a used slug gun, a Marlin 512 Slugmaster, in very good condition. When I shoot it at 50 yards, all shots are pretty much centered as far as windage is concerned. When I shoot it at 100, all my shots are off to the right between 3-5" on a windless day, using a variety of ammunition. I am using iron sights, but at 100 yards I'm shooting at a massive piece of blaze orange poster board with black duct tape as my cross (in other words, ain't no way I can't see "X" perfectly).

Any idea what the problem could be? Could the barrel be bent?

Thanks!

Might be a little flinch, maybe let someone else shoot and see if the results are the same.

Might need to switch your sabot slugs. Could be having problems with stabilization.

I've tried a variety of slugs...I think 5 different types. I still get the same results. I know I'm not flinching; why would I flinch at 100 and not at 50? I don't have a problem hitting the 9 and 10 ring consistently with my M14 using irons at 100 yards.

If I get a chance, I'll have another shooter that I trust shoot a 3-shot group. It's just that sabots are SO expensive...I kinda feel nervous about letting someone else crap $10 out of my gun. ;)

Any other thoughts?

Have you tried re-zeroing the gun for that distance?

HERES YOUR BEST ANSWER!!! Aim 3-5" to the Left then you'll hit right on the money. Its not rocket science. weeeeeeeeeee-hoooo!

Resight it at 100 yards, then see what happens at 50. Your shots are averaging 4" right at 100 the way it's set up now. I bet that when you get the windage zeroed at 100, that you'll be about 2" left at 50 yards.

Yeah, that's what I'm guessing will happen. The question is, why? Not sure if I wanna spend the slugs rezeroing for 100 though, especially since the rear sight is dovetail and those are a PITA to work with.

Are you using a rest?
If so, shoot it from a standing position, or freehand sitting position at 100yds, and see how your groups look.

I do not know the rifling twist on your barrel, but it is common that slower twist barrels stabilize the bigger bore size slugs better. A faster twist barrel will stabilize the newer fancier ballistic tip slugs that are actually smaller diameter better. I know you said you tried a variety of ammo, but if you only tried the newer fancier ballistic tip type slugs, you aren't really trying the biggest variety of slugs out there. You should go get some of those gigantic Brenneke slugs and see if those shoot any better. If you already tried this kind of giant bored slug, well then, I would just zero it at 100 yards and accept the fact that at 50 yards you might be a little off. Better to be off a little up close than a few more inches at 100.

I'e tried Lightfield and Hastings slugs, do you consider those to be the old school type (I've also tried Remington Copper Solids, Hornady SST and Federal Fusion, which look more "modern").

I'm not surprised at all that you're hittling on at 50 but 4-5 inches to the right at 100 yds with iron sights.

I would adjust the windage by moving the rear sight slightly to the left. Brace the gun firmly in a vise with some padding. Apply a strip of tape to the barrel, and another on the sight, close enough to each other so you can draw a line along the barrel across both pieces. That way, when you drift the base in the dovetail, you can tell how much you have move the sight. A minor adjustment is all that's needed.

You're the man. I did just that and nailed bullseye at 100 yards. Made a 1.5" group with 3 sabots. Went back over to 50 yards and was perfect on elevation but off to the left about an inch or so, but I only shot once shot just to save $$$. Used the Remington Premier Tips and they were wonderful. Too bad I didn't find them sooner!!

Sounds like you're good to go.