Point of impact change

I'm having a hard time trying to figure out this muzzleloader. Remington 700ml, Leupold rings and bases, Nikon scope, 120 gr pyrodex rs, #11 Remington percussion caps, .44 cal 240 gr xtp, green harvester crushed rib sabot. Scope and bases are good. First shot from clean barrel is always a flyer it seems. The gun has grouped well after that first shot. This last range trip the point of impact shifted and I can't figure out why.

First shot was right on the money which is unusual. Clean barrel first shot is usually high left. Shots two and three were high left. I adjusted the scope and shot 4 and 5 back on target. The next three shots were shot at 150 yd target and they were high left. The last two shots back high and left at 100 yds. I run a tight dry patch between shots. The barrel wasn't too hot although I didn't wait too long between shots. No wind at all. I'm not a benchrest guy but not the shooter here. I reset the turrets back to where they were and will see if that clean bore shot is repeatable. What do you guys think?

First shot flyers are not unusual. I can't explain why you'd have it shift from time to time unless the scope was bumped in th cleaning process.

Back to the FSF, I believe it has to do with th sabot spinning differently on clean barrel.

How tight does the Green crushrib and the 240 XTP combo fit your barrel? If they slip down the barrel real easy then they may get erratic.

It is tight fitting requiring force to seat the projectile. You can see the two distinct groups there. Clean bore shot then poi moves high left. Adjust scope back to center. Poi abruptly changes back to high left? Weird

I'm thinking scope. Might want to send it back to Nikon and have it checked out, or try another one to see if the problem persists.

I think your barrel might be moving

I wonder if some other owners of your Remington ML make/model could help you here. I'd like to know if ''tight bores'' are common with your Remington. If not, unless you have an unusual / non-common sized bore, you shouldn't need a Crush Rib sabot using the standard 44-cal / 240gr XTPs. In a vast majority of MLs, that would be a darn loose fit.

Also, another option would be to try a different sabot and bullet. That XTP may only like 100gr of powder to be real accurate. You may need to find another sabot and bullet option for 120gr magnum charges of Pyrodex. Try Harvester PT Golds. or their Scorpion HP bullet. Barnes is a nice option, but they're more money per shot.

Personally I would scrap the Pyro RS for some Pyrodex P and drop the charge to 105gr. I've always opted for P/FFF powders in my 50-54-58-cal MLs over the years. Always had better success using the finer, cleaner powders.

I would try a tighter fitting sabot for sure. Rem 700ML barrels are not usually known for being tight bores. The Harvester green smooth will be slightly tighter. The MMP green 50x44 will be much tighter. You don't have very many sabot options if you choose to stick with 44cal bullets.

In ...... general........ when a rifle throws two different groups (all things equal), it could be the shooter causing it too. Slight changes in the type rest, form and trigger finger placement can change the POI.

Mechanically you should check all the fasteners first. You could shoot closer range, say 75yds and when doing so, check to verify that your scope is tracking properly. Shoot a 5 shot group, then adjust your scope to shoot 2" high and 2" right and shoot another 5 shot group. Your POI should have moved 2" higher and 2" right. Then make the adjustment down 2" and left 2", which should bring you back to your first 5 shot group POI. This can eliminate scope issues, which IMO you should do first. You can do the process with just 3 rounds, but 5 is always better. While you are checking that the scope tracks, make sure you do EVERYTHING the same. Solid rest, same form, finger placement on the trigger and loading procedure.
If the rifle's results remain the same, then its most likely time to change the propellant, bullet and sabot combination for improved results.

I figured out what I was doing wrong . I was not letting the barrel cool long enough. I also bought a Lee mold and these cast bullets shoot darn good. They are in the neighborhood of 305 grains pushed by 100 gr pyrodex RS.

100 yd target with cast bullets, a hot bore throws high left. A cool bore looks good to me.

My first batch of cast bullets. 300 gr hornady xtp for reference.

Cast boolits are great for trigger time or hunting. Yes, HEAT is the enemy of sabots!! Waiting for a cool/cold barrel is important. First shot, cold shot should be the best shot! I have found that BCR = black crush rib, sabots and .458 bullets give the very best accuracy in ANY of my 50 cal guns be they smokers(BH209) or SML. My favorite .458 is the Speer 300 FN. Always accurate and great terminal performance. JMHO yours may be different. W