I decided to take the U-mag out and see how it would shoot Saboted bullets. Since it is #11 caps I chose the take pyrodex select along . I think that was a mistake. It seemed like everything I did was a big mistake. I only had cci primers in my bag. I don't like cci. I much prefer Remington. I took along some leftover shockwaves from this morning and some 340 gr dead centers.
I went to 50 yards to see where it hit. tried a couple shots and it wasn't even on paper. I thought it might be shooting high. I adjusted down and still not on paper. I went to 13 yards and shot. It was on paper to the right and low.
I went up 48 clicks . Tried again at 50 still not on paper.
went back to 13. still low and right. went another 48 clicks up, 48 left. tried again. it was on paper at 50 but not great yet. A few more adjustments. and then I gave up and decided to try a new target and just see if it would group.
I got an 6 inch group at 50 yards. I decided to start over another day with different primers( Remington) , different powder, probably triple 7 and different bullets.
I know the u-mag will shoot but my experiment with sabots was a dismal failure.

That does not sound like you or that gun. Some thing loose or warped? If it was me I would be checking every bolt and the scope mounts if I did not find anything I would try a different scope.

You know I think I may have a partial answer for you... You do not say which bullets or which sabots... but that 504 is a generous 504 and you will probably need to use a MMP short Black sabot. Anything like a HPH-24 or a Harvester will be to loose.

I can not really tell from the picture on the hood of the truck - but I am thinking those are probably HPH24 sabots. If you have any of the old Knight sabots for days long ago they would also work but they would be the old polymer formulation.


Nevertheless that gun will shoot sabots... but it used T7 when it was shooting well.

Here is a few of many...







So now you have you work cut out for you...

Try a Harvester black crushrib 50x451 sabot with a .458 bullet. You should have roughly a .509 loaded OD.

Feed that gun what it likes best.... conicals. Disregard what twist it is and insert in it's mouth something that makes you and the ML smile.