Ghost Ring Slug Zero

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Mot45acp

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I am currently trying to get into shotgunning and trying to determine if I have a hardware issue (sights) or a software issue (me).

I have a 590A1 with ghost ring sights (factory front, Aimpro rear) and 20" barrel. The sights sit fairly high over the bore. At 40 yards I am at the very top of my elevation adjustment. This bugs me. I shoot using the tip of the front blade ala AR-15.

I am wondering with my sight height over bore if I am doing it wrong. Is there a BZO distance? Am I too close? Too far? I was thinking of ordering a Big Dot front sight replacement but am concerned about the height. Or should I just shave the front sight a little at a time until I'm happy?

Or is something blatantly obvious and I am just being dense?

ETA: Also looking for a decent light mount. I have the Magpul fore end, dunno how I feel about mounting to it, or a barrel/mag clamp mount. Pros/cons? I see a lot of people mount TLR-1's but am concerned with the rocker switch about accidental activation via bumps etc.
 
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I am currently trying to get into shotgunning and trying to determine if I have a hardware issue (sights) or a software issue (me).

I have a 590A1 with ghost ring sights (factory front, Aimpro rear) and 20" barrel. The sights sit fairly high over the bore. At 40 yards I am at the very top of my elevation adjustment. This bugs me. I shoot using the tip of the front blade ala AR-15.


I presume you are sighting in with rifled slugs.

Some questions and then some suggestions:

Are you sighting in on a bullseye target?

Are you centering the bullseye in the Ghost Ring and then using a 6 o'clock point of aim with your front sight post?

If so, here is my suggestion:

Leave your bullseye targets at home.

Take some letter size blank sheets of paper to the range and staple these to the middle of your cardboard backer.

Begin sighting-in by centering your front sight on the blank sheet of paper.

Adjust your sights to center the group on the center of the blank sheet of paper.

It should then be obvious why you previously ran out of elevation adjustment when you tried to sight in on a bullseye target!

It is a common mistake.
 
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I am using printer paper with a 2" black dot. Splitting the dot in half with the front blade. Front blade centered in ghost ring
 
Well it's apparent that your sight picture is not the problem.

I will just add that a 2" high 50 yard zero with the 590 translates to a 75 yard zero and roughly 4+ inches low at 100 yards with WW 2.75" rifled slugs.
 
Forgot to add: with rifled slugs. Groups are acceptable for my (limited) ability.

I dont think I could adjust enough to be 2" high at 50. But that trajectory sounds exactly like what I want.

I wonder if there is a BZO crossover like the AR 50/200. I may check 25/75 or just go for 75 and see what it does at 25.
 
Other than a possibly the wrong front sight height, the only thing that comes to mind iis how the gun is bench tested. Shotgun sight in must take into account the relatively light weight of the gun and the rather long barrel time of slug ammunition. Rifle bench rest techniques seldom work well with slug guns.

When bench resting a slug gun, it is imperative to hold the forend firmly while resting the back of your hand on the front sandbag. The toe of the stock should be resting on a sandbag and the firing hand must have a firm hold on the pistol grip and pulling the shotgun tight to your shoulder. All this is to prevent excessive barrel movement while the slug is still in bore transit.

Simply resting the forend on the front sandbag, as many do with rifles, will virtually guarantee excessively high slug impact.
 
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