Not sure if this belongs here or in the wildcat forum but here goes:

Sauvestre makes a fin-stabilized .45 projectile that is accurate to 400 meters. The sabot round has a high sectional density and halfway decent ballistic coefficient.

Is there any real limitation to loading something similar and being able to hit a target out to 400-500 meters or beyond?

I'm aware that MOA accuracy is off the table with such a setup and this is not being used for hunting. I'm strictly curious. I just want to try this for fun.

What are your thoughts?

I'd experiment with an aluminum fin stabilized discarding sabot for that kind of shooting. You need high velocity and low drag. Like an Abrams tank AP round.................

https://en.wikipedia.org/wiki/M829

I went through a stage trying to find a slug accurate for my gun at ranges greater than 100 yards and for a time spent more time and money on that goal than I spent for all my rifle and pistol reloading/load development combined. Speaking for myself, I was not able to do so. My take-away from all of it was that in my experience the accuracy went to pieces when the slugs went through the trans-sonic zone. If you could keep a slug from going trans-sonic (appx 1600fps) you can probably keep your accuracy. If you know the BC, you can calculate what velocity you need at the muzzle to remain at or above 1600 fps at whatever yardage the target is. I found roll crimping to be the most consistent and did not re-use spent shells, I suspect brass shells with a consistent/firm crimp on a rigid sabot would help.

I'm curious to follow this thread and any info/data on a sabot round.

Here are two links to info on long range shooting (up to two miles!) of the .45-70 at shotgun MV's:

http://www.researchpress.co.uk...dy-hook-1879?start=1

https://www.google.com/url?sa=...0QQabSVRFDPMPDAR9e_3

Looks like your modest goal should certainly be doable.