I know the answer but maybe I am missing something.

[ar15jules]

I'll make a short story long. I was fortunate enough to have my wife purchase an inline muzzleloader last year. It is a T/C Impact. It came with a 3-9 scope marked T/C. A little Google research indicated that the scopes they include on their package rifles are made by Simmons. I finally shot the rifle last year before the deer season using the following loads.

120 grains of Blackhorn 209.
250 grain Hornady Monoflex ML in a Hornady High Speed / Low Drag sabot
CCI 209M magnum shotgun primers

After sighting in, and cleaning between every 5 shots or so, I was able to group three shots close to if not IN a cloverleaf pattern at 100 yards.

Using Blackhorn, I cleaned with traditional gun cleaning products. Breech plug cleaned thoroughly with a 1/8th drill bit, a torch cleaning pick, bore scrubber and air compressor.

I went to the range with the rifle several times last year with no issues using the method described above.

I need to add that after taking the rifle from the box, I removed the scope, rings, and one piece base. Degreased the screws and holes before remounting with blue thread locking compound and an inch pound torque wrench. Bore sighted then fired.

If I had to estimate, I have put about 20 very well placed rounds down the barrel.

Fast forward to last Saturday's range session.

I was in a hurry, so I laid a roll of electrical tape on a paper plate and filled in the "ring" with a black Sharpie.

First shot, four inches right with perfect elevation. It never needed a fouling shot before, but I figured maybe I had some excess oil in the barrel. I had fired a primer to clear the flash hole. Second, third, fourth, fifth and sixth shots bounced all over the damn plate. Did it maintain minute of deer vitals the entire time? Absolutely. Was I happy with the "pattern".....no. I maintained the same stock to rest position for each shot. Had my friend fire a couple too. I left the range frustrated and out of projectiles.

When I got home, after pulling the breech plug and swabbing the bore, I anxiously checked all of the action screws, and ring screws hoping that something had come loose. No dice. everything was good. The only thing I didn't check were the screws holding the base to the receiver as I would have had to remove the scope.

So.....now I am suspecting that the scope may not be holding zero. I was planning on letting a new hunter use this for the early ML hunt this October, and really want the rifle to shoot to point of aim. Again, the "group" is probably about a 6" extreme spread and in all reality more than accurate hunting doe where a long shot will probably be less than 50 yards. Had the rifle shot like this out of the box, I wouldn't be super happy, but I wouldn't be pissed like I am now. I have the option of stealing a Nikon Slug Hunter from a shotgun, but I don't really want to mess with that setup that hasn't moved from zero since being mounted. Not only are 12 gauge slugs non-bench friendly, but expensive.

I know in my heart that my scope is boogered up and will probably get progressively worse with continued range trips. BUT in the event that I am overlooking something obvious maybe you inline pros can chime in.

Thanks,
Jules

[DrillNFill]

I've been using a T/C Impact for ~5 years now. Package with the mounted and boresighted scope from Cabelas.
If you're getting a cloverleaf pattern on paper @100 yards you're a better shot than I I'm happy with getting all my shots on a pie plate.

I don't think I can offer any advice other than that my scope still seems to function the same as it always had. Im not sure if I have the same scope model as you, I believe it's a Bushnell, it seems to get the job done.

I don't know if powder vs Pyrodex makes a difference, but I use 2 Pyrodex pellets with 240gr Powerbelt .50cal bullets and Winchester Triple Seven 209 primers. Come to think of it, I did try a heavier Powerbelt bullet once i bought by accident and IIRC accuracy seemed to suffer. don't know if that has anything to do with it.

Best of luck in your quest for accuracy

[Badger Tuff]

Sounds like a scope problem but are you using the same load? How old are your sabots and powder because if not stored right they can deteriorate which would affect accuracy. Also check the front of your breech plug for any carbon or black powder residue build up as that will cause your powder charge to burn erratically which will also cause accuracy problems.

[ar15jules]

Sounds like a scope problem but are you using the same load? How old are your sabots and powder because if not stored right they can deteriorate which would affect accuracy. Also check the front of your breech plug for any carbon or black powder residue build up as that will cause your powder charge to burn erratically which will also cause accuracy problems.

Thanks for the reply. Breech plug was spotless throughout when i started. Blackhorn was stored in its original container and in a metal ammo can along with a can of FFG black powder. Ammo can stored in a cool dry space. Projectiles and sabots stored in a garage cabinet.

[Badger Tuff]

Thanks for the reply. Breech plug was spotless throughout when i started. Blackhorn was stored in its original container and in a metal ammo can along with a can of FFG black powder. Ammo can stored in a cool dry space. Projectiles and sabots stored in a garage cabinet.

That eliminates 3 problems, I'd try a different scope, maybe use that one off your shotgun just to see how your MZL groups.

[bigandy1966]

does the rifle have irons? see if you get same issues with the iron sights at 50yds. grab the scope and give it a twist, if its loose enough I think you would be able to feel it.

[Bang]

If I read correctly, the scope mount base remains an undetermined status and has not been eliminated as the problem. I don't understand why the skip-over.

I discovered a bad scope one day when, thinking there might be a shot remaining, I "fired" on an empty chamber. I clearly saw the reticle jump. Dry-fired it a second time and verified. It had been printing much as you describe. Was a friend's rifle who had asked me to look at it.

[ar15jules]

If I read correctly, the scope mount base remains an undetermined status and has not been eliminated as the problem. I don't understand why the skip-over.

I discovered a bad scope one day when, thinking there might be a shot remaining, I "fired" on an empty chamber. I clearly saw the reticle jump. Dry-fired it a second time and verified. It had been printing much as you describe. Was a friend's rifle who had asked me to look at it.

I verified the rings and ring to base torx to all still be snug
When I mounted, I decreased and used blue thread locker. To check the base screws I need to physically remove the scope. As it seems i will be starting over anyways, I will go ahead and do that some evening next week. I suspect the base will be rock solid and I can toss the glass in the trash.

[ar15jules]

Worse case scenario i can use the irons. Nice fiber optic front.