Loss of accuracy, slug gun

[Superkodiak38]

Anyone had an issue with a 20 gauge Mossberg ported, rifled barrel loosing accuracy ? My kid has one that new out of the box shot a cloverleaf 3 shot group with iron sites at 40 yards. It has killed a bunch of deer over the last 10 years. Last year I mmmmmmissed with it then, killed a doe but the impact was 5 inches high and 3 or 4 inches right of my point of aim. Yesterday I took a box of Hornady SST's, same thing we always shoot and shot a pretty pitiful group at 25 yards ! 1st shot 4 inches high, second was 4 inches high 5 or 6 inches right, third was high and a little left. I was seated on shooting sticks and was dead on it. I shot my 45-70 after that using the same chair and sticks and shot great groups. I assume it's the barrel ? I would estimate maybe putting less than 75 rounds through the gun in the last 10 years. Any thoughts ? Thanks !

 

[Vids]

I have had trouble with specific loads in my slug gun, so maybe try switching to a different slug. For some reason one year when I went to sight in I was all over the place with Hornady's when they had shot fine in the past. Switched to Federal and I was shooting good groups again. Nothing against Hornady, I think it was just the combination of that slug with my barrel, and maybe they had changed something in the slug, who knows. That is with a Remington 11-87 with a rifled barrel, FYI.

 

[Superkodiak38]

I have had trouble with specific loads in my slug gun, so maybe try switching to a different slug. For some reason one year when I went to sight in I was all over the place with Hornady's when they had shot fine in the past. Switched to Federal and I was shooting good groups again. Nothing against Hornady, I think it was just the combination of that slug with my barrel, and maybe they had changed something in the slug, who knows. That is with a Remington 11-87 with a rifled barrel, FYI.

I appreciate the info ! I was wondering it it was a bad lot of slugs. I have never had an issue with Hornady's but maybe they had some quality control issues. I will pick up some different ones to try and hopefully find something else that fly's well. A friend told me he has had some success with the Lightfields maybe I will give them a go.

 

[Downeaster]

May or may not pan out, but my first thought was plastic buildup from the sabot. I use acetone to periodically remove.
You didnt mention cleaning plastic buildup out specifically so I figured I would mention.
Hope that helps.

 

[Superkodiak38]

May or may not pan out, but my first thought was plastic buildup from the sabot. I use acetone to periodically remove.
You didnt mention cleaning plastic buildup out specifically so I figured I would mention.
Hope that helps.

That's a great observation and I never thought of it so thank you for that. I will for sure give acetone a try !

 

[Wapiti1]

Plastic fouling was my thought as well. A hot day will make sabots shoot terrible as well. Check the obvious things like the barrel screw, scope rings, etc.

I have the same setup on a 20ga Mossberg 500 and have never had issues with accuracy. That barrel has about 300 shots through it, both sabot and full bore slugs. My most accurate loads are Winchester 3" 260gr bonded in that shotgun. It shoots about 1.5" or less with those. Hornady SST shot around 3".

Jeremy

 

[rayporter]

^^^^

 

[Tod osier]

Anyone had an issue with a 20 gauge Mossberg ported, rifled barrel loosing accuracy ? My kid has one that new out of the box shot a cloverleaf 3 shot group with iron sites at 40 yards. It has killed a bunch of deer over the last 10 years. Last year I mmmmmmissed with it then, killed a doe but the impact was 5 inches high and 3 or 4 inches right of my point of aim. Yesterday I took a box of Hornady SST's, same thing we always shoot and shot a pretty pitiful group at 25 yards ! 1st shot 4 inches high, second was 4 inches high 5 or 6 inches right, third was high and a little left. I was seated on shooting sticks and was dead on it. I shot my 45-70 after that using the same chair and sticks and shot great groups. I assume it's the barrel ? I would estimate maybe putting less than 75 rounds through the gun in the last 10 years. Any thoughts ? Thanks !

I know that when my slug guns shoot badly it is usually the guy behind the trigger flinching.

 

[Superkodiak38]

Lol,, well I can't say I have never flinched but at 25 yards I can normally keep them close ! I did shoot my 45 70 after that and shot a decent group, I put a limbsaver slip on recoil pad on that beast and it tamed it quite a bit.