What happened to my accuracy?

[Amaaho]

I have a CVA Optima in .45. In June, I set it up and put 2 50gr Pyrodex pellets underneath a 245 grain Aerotip Powerbelt. After a few scope adjustments, I could put a two inch group at 100 yards. I cleaned it. Put it away until August confident in a 100 yard killing range. In August, I pulled it out, went to the range and could not hit the broad side of a barn. I can hit 50 yards with no problem. It hits two inches high at 50 yards. Just about where I would expect it if I was centered at 100. Anything beyond 50 yards goes wide right. Really wide. Any guess what the problem is? Before you ask, I checked the scope mounts. :?

 

[snshunts]

Did you check the scope itself?

The scope I used on my slug gun developed an internal problem that allowed the cross hairs to rotate in the tube while I adjusted the power setting. Unfortunately found this out after missing a couple of nice bucks, that according to paper earlier this fall should have dropped in their tracks.

 

[Redclub]

If its not the scope try this, Give the rifle a very good cleaning with a stiff brush,
Powerbelts are fine but be sure the skirt comes off, before you shoot rotate the skirt or better take it off and put a little bore butter or similar on the post beneath the skirt, only a very little tho. I seen this happen numerous times.
Redclub

 

[American Me]

I have heard that bore butter actually gums up the rifling and worsens accuracy. Anyone else experienced or heard the same?

 

[cayuga]

Take a good solvent and brass brush and like Redclub said, clean the devil out of that barrel. Then be sure the barrel is good and dry before you shoot. Don't swab between shots when you shoot powerbelts.

 

[Cajun]

If its not the scope try this, Give the rifle a very good cleaning with a stiff brush,
Powerbelts are fine but be sure the skirt comes off, before you shoot rotate the skirt or better take it off and put a little bore butter or similar on the post beneath the skirt, only a very little tho. I seen this happen numerous times.
Redclub

I have read about several cases on the internet about the skirt not coming off and causing accuracy problems.

 

[Spitpatch]

RedClub is correct. Bore butter, vaseline, breach plug grease, all work.

Remember, an accurate 100 yard load is not necessarily an accurate 200 yard load.