My gun shoots HORRIBLE when I clean the barrel.

[New York Hunter]

I shot my 11-87 Sportsman Deer 12 ga. (2-7x33mm Leupold Shotgun Scope) last Saturday. I shot 4 to 6 inch groups at 100 yards with 4 different brand of slugs (SST, Core-Lokt Bonded, Accutips, Fusion). I shot a awesome 3 shot 2 1/2 inch group at 100 yards with Federal's Barnes Expander Tipped Slugs. I was also switching back and forth between my 2 different slug barrels.

Today I completely cleaned my whole gun. I bought 4 boxes of the Federal slugs and went back to the range to set my zero at 100 yards. First I shot 5 shots at 50 yards and only hit the target ONCE! I couldn't beleive it. The target is about 15 inches wide and 2 feet tall. I took my barrel off and put it back together. I shot again. I hit the target 2 out of 5 times at 50 yards, about a 15 inch group. I shot out to 100 yards and didn't even hit the target.

I had a box of 2 3/4" Remington Buckhammer slugs. I shot about a 3 inch group at 50 yards with them. Every time I clean the barrel, I can't get it to group until it gets really dirty.

I'm going to try some more Buckhammers and see if it will hold a sub 4 inch group at 100 yards. I it can't do that, it's no good to me. I'll hunt in the rifle part of the state (half hour north) and I'll part this gun out over the winter. I'm pi$$ed. This is getting way to expensive. I had the same problems with it in 2007. I didn't even both messing with it last year.

Will the Buckhammers load up the rifling in my barrel? If so, what's the best way to clean it?

[torpedoman]

not an uncommon experience, quit cleaning it.

[New York Hunter]

Cleaning it shouldn't make that big of a difference.   I could see it being off a little for the first shot or two, not the first 20 shots though.   

[New York Hunter]

Forgot to add, I took the scope off and I'm sending it back to Leupold again.   I sent it back during the 2007 season because I could hear a clicking sound when I shook it back and forth.   I didn't use it until last weekend since getting it back.   Sometimes when I made an adjustment it took about 10 shots go get it to hold a zero.   

This is the third gun I've had this scope on.   It was ok at best on my Marlin 336C 35 Rem. the recoil is very mild.   Once I put it on my 870 12 ga. it got worse.   I sold the 870 and the guy that bought it put his own scope on it and it shoots pretty good.   I'm having the same problems with it on my current 11-87 12 ga. as I had when it was on my 870 with the exception of the clicking sound.   Leupold fixed that problem.     

[spikehorn]

Get a diffrent scope

[Arier Blut]

I leave all of my barrels dirty until accuracy falls. I don't think that is your problem. It may be the difference of a few inches not feet. You have a mounting/scope problem. The mounts most likely need loctite The mount on a slug gun needs to be a weaver drilled and tapped into the receiver. No cantilever barrel and no pin mounted receiver cover. My encore runs 2.5" groups on a bad day with buck hammers at 100.
Good Luck

[JimFromTN]

Get some gun tite/lock tite and put it on the screws on your scope rings.  If I had to guess I would say it has more to do with taking the gun apart than cleaning the barrel.  You can test this by getting it to shoot the way you like it and then just cleaning the barrel without taking it off the gun.  You might consider pinning the barrel.

[GLHolmes]

Well, what do you guys think about smoothbore barrels?
Starting with a perfectly clean barrel, shot a box of Federal Truballs out of my Mossy 500 12 gauge the other day; taking all five shots, it was a six and a half inch group at fifty yards (somewhat unacceptable in my mind).  Taking just the last three shots, it was an incredible 1.25 inch group @ 50.
So what do you think?  I've got more of these slugs and a couple of weeks before gun season opens here in Michigan; I have not cleaned the barrel since shooting it yesterday.  What should I be doing?
Thanks.

[JimFromTN]

Is this a smoothbore with rifle sights.  If not, are you using any kind of sight?  A smoothbore with a bead sight is the least accurate you can possible get.  First suggestion would be to get some kind of sight if you don't have one.  If you don't have any money, I think you can get magnetic rifle sights or something that you can stick on your gun for $20.  If you have $100, you can get a saddlemount with a cheap 2x scope or some kind of cheap red dot. The point being to have a reliable sight.  2nd, buy more trueballs and shoot more.  You will get flyers and tumblers with cheap slugs. As for cleaning, with a smooth bore, I would not bother until after the season.

Other slugs you may consider would be brenneke black magnums and fiochi.  I really like the fiochi 1oz, 1560fps slugs.  They run about $8.50 for a box of 10.

[GLHolmes]

Yes, it does have rifle sights; only thing with the saddle mount is that I also birdhunt with this gun, so it's not a "dedicated slug gun."  I do have a rifled, cantilevered barrel on the way from Cabela's, but I'm still just trying to figure this barrel out!  I've tried Remington sluggers, Winchester Super X rifled slugs, Brenneke K.O.'s, and now Federal Truballs.  Everything I've read about the Truballs is that they are THE slug to put through smoothbore barrels for best accuracy and they are the only slugs that have come close to grouping for me.  I suppose it sounds kind of crazy, but I guess what I'm wondering is whether or not I need a somewhat dirty smoothbore barrel to get best accuracy.  I'll go ahead and shoot another box of Truballs and see what happens.  Everyone's thoughts continue to be welcome.

[KenSel]

my new Mossy 500 20ga. does the same thing with the first shot after a run a boresnake through the barrel.  my first shot is usually about 4" to the left of the rest, but after that shot it shoots consistent for the next 5 shots, maybe more but I swabbed it every 5 shots to try out different loads.  I'm gonna leave it dirty next time I leave the range and then see if the difference in impact is also because of a cold barrel, if not then I'll just leave it dirty through hunting season.

[GLHolmes]

Thanks for the post, Ken!
That is a smoothbore barrel, right?

[KenSel]

GL,  sorry no it's the fully rifled barrel.

[spikehorn]

Mossy smooth bores don't seem to group well, my sons 20ga wouldn't group anything very well at all i ended up getting a riffled cantalevered barrel for it. now the only time it wears the smooth bore is if we are doing drives.

[1marty]

I have a Rem 870 rifled barrel. I mounted a scope and like you it wandered all over the place. I decided to take it off years ago and shoot Win 1 oz sabot which the gun loves. Since I hunt in heavy woods most of my shots are 50 to 75 yards max. I get 2 inch groups at that range. Usually I just run a fuzzy to clean the barrel. Many people get scopes and unless you are hunting wide open country iron sights are fine. Simple is sometimes better.

[JimFromTN]

Yes, it does have rifle sights; only thing with the saddle mount is that I also birdhunt with this gun, so it's not a "dedicated slug gun."  I do have a rifled, cantilevered barrel on the way from Cabela's, but I'm still just trying to figure this barrel out!  I've tried Remington sluggers, Winchester Super X rifled slugs, Brenneke K.O.'s, and now Federal Truballs.  Everything I've read about the Truballs is that they are THE slug to put through smoothbore barrels for best accuracy and they are the only slugs that have come close to grouping for me.  I suppose it sounds kind of crazy, but I guess what I'm wondering is whether or not I need a somewhat dirty smoothbore barrel to get best accuracy.  I'll go ahead and shoot another box of Truballs and see what happens.  Everyone's thoughts continue to be welcome.

A saddle mount can be taken off and on the gun with ease and do keep your POI to some extent.  They are not as good as taking off and on a cantelever barrel.  As for the slug, no one slug works in every barrel so truballs may work great for someone with you exact same setup and it may not work for you.

There is one test you might try if you have not already and that is to clean the barrel without removing it from the gun.  Loosening and tightening the barrel nut can affect the POI.

[gunrac]

Forgot to add, I took the scope off and I'm sending it back to Leupold again.   I sent it back during the 2007 season because I could hear a clicking sound when I shook it back and forth.   I didn't use it until last weekend since getting it back.   Sometimes when I made an adjustment it took about 10 shots go get it to hold a zero.   

This is the third gun I've had this scope on.   It was ok at best on my Marlin 336C 35 Rem. the recoil is very mild.   Once I put it on my 870 12 ga. it got worse.   I sold the 870 and the guy that bought it put his own scope on it and it shoots pretty good.   I'm having the same problems with it on my current 11-87 12 ga. as I had when it was on my 870 with the exception of the clicking sound.   Leupold fixed that problem.     

Why don't you just pop your rifle scoop off, if it is a proven scope. See if you can get a group with it. Should answer a lot of your problems an questions.. You probably should leave the barrel on until after the season ends.

[New York Hunter]

I sent the scope back today.   I'm taking my barrel to my friend.   He's going to lap the rings and make sure the rings and the cantilever mount are set up the way they're supposed to be.   He has a ton of shooting experience and knows a lot more about setting guns up with scopes then I do.   Truth be told...I should have let him set it up to begin with.
       

[hunt-m-up]

Not a fan of the cantilevered mounts. I like the drilled and tapped'd receivers(best) or the (ugly) saddle-style mounts better, I think they allow the whole gun to absorb recoil along with scope. 

Smoothbore Mossy barrels I've had were accurate to 4-5" at 100 yards and liked Winchester 2 3/4" Foster style slugs as well as the Brennekes. I think you'd find some variation in Mossberg smoothbore barrels that accounts for different taste in slugs and the fouling actually making the bore tighter/better.

[New York Hunter]

I got the barrel back from my friend today.   He said the rings were the best set of Leupold rings he's ever seen.   He said he always has to lap Leupold rings.   He said my rings didn't need any lapping at all, they were right on.   The cantilever mount was fine too.   

[New York Hunter]

I got my replacement VX-II 2-7x33mm scope back from Leupold yesterday.   Mounted it up and went to the range today.   I shot a 2 1/2 inch group at 100 yards using Lightfield slugs in my 11-87 12ga.!

I have a picture of it on my cell phone.   However I don't know how post them.  

[Varmint Hunter]

Sounds to me like you found the problem.