Are these good guns and accurate?

Magnum bob, I have two of them, the original factory 54 is my go to just because it shoots well, 1 1/2 at 100yards and it has one of favorite scopes of it, burris FF 6x. The second rifle was original 50cal barrel was rusted out. I Got the gun for 50 bucks. I had it rebored to 54 ,same outside barrel diameter by taylor machice. The bore on it is tight and it is tough to seat a 45 cal bullet in a 54 cal sabot. I have not shot it much. 44 cal bullets in a 54 cal sabot are easier to seat but do not shot well at all. I may try 451. 45 acp bullets and see how it does Both guns are set up for 209 primers. I do not like the tupperware stocks but they get me by as is.

Many upgrades for the Rem700 SA fit the Rem700ML. Stocks, triggers, scope bases ect ect. The 209 system sorta sucks but Badger Ridge offers one made by a guy who goes by Hunter on Dougs board. That 209 conversion is excellent and works with Blackhorn209 powder. I would shoot 54x50s if i got one. There are a bunch of good 50cal bullets for those sabots. A couple are dirt cheap at Midway and Grafs. Try the Harvester 54x45s if you want a very strong sabot for 45s. If your bore is a bit loose you may be able to shoot some 458s instead of 452. Otherwise it loads a little easier than the MMP 54x45 sabots when you use a 452 bullet.

If the gun is in very nice shape its worth trying.

As they come from the factory.... they suck. But if you upgrade the breech plug and do a bolt nose kit modification to the bolt, they're about as good as anything on the market today. Not sure I would bother messing with a 54cal though.

https://www.arrowheadrifles.com/product/700ml-replacement-plug/

https://www.arrowheadrifles.com/product/700ml-bolt-nose-kit/