trouble sighting in for slugs

[dodgeboy12008]

I have a Mossberg 500 turkey with the factory fiber optic sights on it. I was wanting to use it for slugs this year but after adjusting the sights, it was shooting about a foot and a half high with three different slug loads. Im thinking I will just get a scope for it but it makes me wonder if it will also be off with turkey loads for the spring. If there are any suggestions on how to get it sighted in, they would be greatly appreciated. Thank you.
The barrel is the stock smoothbore and i was using a imp cylinder choke with rifled slugs.

 

[61Woody]

You didn't state your sight in distance but 1.5' high is pretty extreme. Could be many different issues, I'm guessing it may be the way you look at the sights and also they were not made for precsion shooting.
I would not mess with with the stocks sights. If you are comfortable with iron sights I would just by a slug barrel and not mess with removing/mounting the scope every year, if you want the scope then opt for a cantilever mount rifled slug barrel, that's how my set up is and it takes less than a minute to swap out.

 

[dodgeboy12008]

I had the target set up at 50 yards. I also had another person shoot just to make sure it was the gun and not me.

 

[Jason_W]

Some turkey barrels are overbore in that the chamber is a 12 gauge but the diameter of the bore is actually more or less ten guage. If this is the case with your model, that could account for your issue.

Beyond that, shotguns are typically very picky about slugs. It may simply not like the brand you're trying.

 

[chas08]

Pattern it with a turkey load at the same distance, with the same setup, you have for slugs and see if it is high with them also! I'm betting it's the slug shooting high and not the gun! A 500 doesn't come from the factory overbored, so that shouldn't be an issue.