Got a Mossberg 500a 12 gauge I took on trade last year. Tried at 15 yds with target load #8. Also shot 3" # 4 at 30 yds. Either way you'd miss a squirrel, or a turkey. It has the big white factory front bead. If it were patterning high I could easily adjust. 90 something model so it's not tapped for scope. Any suggestions that are not sarcastic? It'll be tough, I know.

There was a thread a few days ago. Have you tried smacking it on a tire?

I'd have to verify the barrel wasn't straight 1st which I'll do shortly.

Add a cheek riser. Trap shooters have used them to raise the pattern for rising clays.

I've got a leather one I made for a bolt rifle. It's a 1/2" to 5 /8" overall. Reckon that might work.

Contact Bristoe, he can teach you how to beat the fuqk out of it till it's straight.

Lemme see if it's crooked, then I'll contact him. I believe with a vent rib it would be hard to change.

You could get a saddle mount that goes over the receiver and then you could mount the optic of your choice.
Bsquare I think makes one.

Install a smaller height bead and or a universal 1/8th or 1/4th" positive / negitive pitch spacer under the butt pad.
Easy to solve problem
IIRC you want positive pitch which means the thick part of the spacer is on the toe and not the comb.

Google fu is your friend.

Shim your scope mount.

Thought about saddle mount rail, but how good are they? Also considered smaller bead as Renegade said. I'd have to remove midbead if I go to a small one.

Actually a smaller height front bead in conjunction with a mid bead is GTG.
The mid bead will force your eye to bring the smaller front bead above it raising impact.
Might be your 10 buck solution.
And you might not even need a pitch spacer.

Maybe that fat bead you got on front aint the original either.

I bet it was brass and brass.
JMO.

What exactly are you trying to do??
Turkey gun set up????
Squirrel/ birding/ dove gun?
Is this gun fixed choked??

Aim high.

You’re welcome!

I'd like to bust a turkey with it. I prefer a bead over all else. I like to keep things as simple as possible.

Came with a improved cylinder & a Carlson full flush choke. They both shoot low. I need to get a good tight choke & to from there.

Meadow creek mount on the rib, then get a vortex venom to put on it.

You can also try different choke/shell combinations

Bennelli offer spacers,of different thickness that goes in the front of the stock. It essentially adjusts the angle of the rest of the stock, and thus your point of aim( I.e. hitting high or low) Not sure if you can do this to your Mossberg or not, but it would fix your problem.

I've got a check riser I'll try first as suggested by Dog Tick. If that doesn't cut it I'll get a smaller front bead.

If you can find a truglo strut stopper extreme not gobble stopper.

Give the SSX a try.
They throw good patterns.
Try 3 inch hevi 13 # 7,s
Or 3 inch mag blend 5,6,7
Or win LB 3inch # 6

All should throw a good pattern with a SSX.

Do you market these ? I'm looking for something like that.

A man could’ve kill one of these today with a bent barrel

Bachelor group out for stroll

LOL

Are you making an 8 with the mid and front bead or lining them up?

Front bead should be stacked on top of the mid bead like it is sitting up on it.

I was making pancake holsters, guitar straps & gun slings. I bought a piece of leather & went crazy. It didn't work on shotgun ( to high). I just filed the bead down. The leather riser was a project to beat boredom. It's not being used, but it looks good & would work if needed. If you want it PM me & I'll send it to you.

Yes I was looking right down rib making an 8. Now that you've said this maybe I shouldn't have filed down bead.

+1 You want your optic on the barrel so zero doesn't wander as the barrel moves around in the receiver. There are a few different ways to mount a dot sight on the rib. Get a decent quality dot. Turkey loads kick like elephant guns.

Did your mossberg not come with stock shims. Believe me they can change the point of impact. I found this out when shooting birds and I was having issues made the shim adjustments and bam right on the money. I knew from years of shooting that it wasn’t me.

My, what an astute observation.

If the front sight has enough height and you would replace it anyway, just file it down until it's correct and then use it - or get a replacement of the same height.

Did Mossberg offer different ribs for different purposes?
A skeet rib is different than a trap rib..
Trap guns shoot high for rising targets. I think a skeet might be low.

I filed it down about a 1/3. I'll shoot it again tomorrow.

As was mentioned earlier, if you are determined to stick with a bead front sight, the ONLY way to make the shotgun shoot higher is to raise the position of your head on the stock. Get a cheek pad / stock riser that comes in multiple layers and go shoot, adding them one at a time until you get the elevation you need. There are several brands of foam or gel pads that will help you shoot accurately and at the same time, soften the kick of those turkey loads. You'll have to be careful to only add height to the stock, not thickness - or you'll see your groups moving off to the side of your point of aim as your eye moves farther away from the stock.

You can do it out of leather if that suits you - just get a roll of painter's tape and keep adding layers to the top of the stock where your cheekbone rests. Once you've determined the correct height, you can make it semi-permanent with the addition of an appropriately sized leather pad.

The SIMPLEST fix, however, is to clamp a red dot sight to the vent rib of that Mossberg and just dial in the correction. Many manufacturers make such a mount, and red dot choices are endless.

PS: stock spacers would work, but I've never seen them made for a Mossberg.
PPS: filing down the front bead will also raise your point of impact, but it sounds like you need a LOT of adjustment, and such a small change would likely not be enough.

I've got a burris fastfire 3 mounted on something else. I may try to use it if bead doesn't work out.

The Fastfire will do a great job with a sturdy mount.

Mossberg 500 stock shims

These work like the ones for Benelli. I used them on an 835 and tuned to my frame without issue.

Best (and cheapest) solution, right there.

If barrel straight the choke tube area might not be machined correctly.

Seen that on some other barrels.

Clamshell mounts work.

Barrel slop in receiver should not be an issue unless running slugs and optic on receiver.
Even then it should be minimal and can be fixed

Had to tape up an 870 bbl to snug it.

BFD, jive, turkey.

Did I not just say shims I few lines up!