12 ga slug gun problems

[gary bartlow]

For several years I have had a Hastings rifled barrel with a cantliever scope mount on my 870 deer gun(12 ga).And for the ENTIRE time that I have had it i have had nothing but accuray problems.I was using a low end (cheep) rifle scope.I thought that was the problem.Bought a more expensive rifle scope,no better.Bought a high end shotgun scope thinking that the problem was solved.NOPE.


Here is the problem.I sight it in,and get great groups,but the more I shoot the farther off the scope is.I clean the barrel,tried SEVERAL diffrent slug types,brands,and loads,still same problem.I even thought I might be bumpin it around to much.I'm at my wits end with this dadgum thing and am about to wrap it around a tree.I have just this past week found another guy with the same barrel and same problem.

Suggestions? Comments?

[Phoneman]

9 out of 10 times the rings are working loose. Since it is a cantilever mount It would not be how well the barrel fits to the reviever. And you've tried different scopes. I would look at the type of rings you have. I mount scopes for people all the time and most of them will buy a highend scope and rifle and cheap tasco rings. They normally come back after the first range visit to get better ones. You should always check your rings to make sure they are not coming loose after a couple of shots. Especially with a hard kicking shotgun. Good luck

[Busta]

Sounds like there is too much play between the barrel and receiver. If you can turn your barrel in the receiver, and I'm sure you can, you have too much play. You might have a barrel that is at the low end of the specs and a receiver that is at the high end of the specs.

I had a beautiful 1100 LT 20 slug gun I bought new back in 1988. It was gorgeous looking, but couldn't hit the same 55 gallon drum twice at 50 yards. This was a dedicated Slugger and was not cheap. The problem was the receiver opening diameter was either over spec or the spec was too large. I could grasp the barrel and turn it at least .100" side to side in the receiver. To make a long story short...after no less than 4 different barrels and a magazine tube...MANY trips to Ilion NY...the thing never shot better than a foot at 50 yards. That is until I shimmed the slop out of barrel and the receiver, then it would at least put them all in a paper plate at 50.

The best fix for a dedicated slug gun today is to have the barrel pinned to the receiver. This is accomplished by having a smith drill through the side of the receiver and barrel tang (for cantilever mounts), or through the top for open sighted barrels, piloting the receiver and tapping the barrel tang. This locks them together and cuts down on vibration as the slug wobbles down the barrel. Any smith worth his salt should be able to do this for you.

[GLHolmes]

I have been having the exact same problems with my scoped Mossberg 500 with cantilever barrel.  Come to find out, the allen screws in the rings had actually been oiled (presumably to prevent rusting while on the shelf), and were coming ridiculously loose.  Take them all out and put loc-tite on them.  With ammo as expensive as it is, it was a painful lesson for me to learn.

[unclematt]

Removing oily screws and adding Lock-tite will give you oily Lock-tite.

Remove the screws and FULLY degrease them and allow them to FULLY dry. Them a dab of low or meduim strength Lock-tite on each screw. Just a drop on one side will do ya on those fine thread screws.

[GLHolmes]

Obviously matt.
Busta, I'm not quite sure I understand your reasoning.  If it's a cantilever barrel, the scope is attached to the barrel, not the receiver, and negligible barrel/receiver play shouldn't be a problem for him.  If it were a receiver mounted scope, then pinning the barrel would make sense to me (if, like you say, it is a dedicated slug gun).  The key is ultimately to maintain scope/barrel alignment.