I've had much better luck than Frogo with sabots although most of my experience with rifles involved loading them for a .308 Remington Model 700 with a 1/10" twist barrel. That rifle would usually group 5 rounds around an inch and a half to two inches at 100 yards with blemished Nosler .224" 50 grain flat base soft points loaded into sabots. It's not all good news though, there would be occasional unexplained flyers that would open groups up to over 5 inches.
http://www.shootersproshop.com/nosl...ts/nosler-22-50gr-flat-base-spitzer-blem.html
Using fairly light (actually bullet length is what's important) flat based bullets seems to be the key to decent accuracy.
I've had poor accuracy with every boattail bullet I've tried and even flat base bullets over 55 grains didn't shoot very well (though nowhere near as bad as FROGO's results).
My theory is that the more bullet that's in contact with the sabot, particularly bullet base, the more spin the bullet will take from the sabot as it's spun up by the rifling. While traveling down the barrel there's a lot more pressure on the base of the bullet than there is on the sides. The outside of the bullets base also has more "mechanical advantage" than the parts nearer to the bore centerline (to envision this, imagine loading a pointed bullet backwards into a sabot, there would be a very small area in contact with the sabot base and the bullet would spin easily within the sabot).
I don't believe that even flat based bullets are capable of taking all of the spin imparted by the rifling to the sabot. I don't know the actual percentage of rotation lost due to the slippage of the bullet within the sabot, but my guess is that it's significant.
Since bullet stability is a function of RPM and bullet length, loss of rotation means loss of stability. If a 1 in 10" twist barrel only gives the bullet within the sabot RPM's equal to a 1 in 14" twist, you're going to have to shoot a shorter and generally lighter bullet.
You can save a few bucks buying your sabots at the site linked below.
I've purchased from them a few times and recommend them highly. Shipping is quick and their prices are reasonable.
http://www.jdcomponents.com/store/prodocts.html
You don't need the "Sabot Setter", a piece of hard wood with a small hole drilled in it works fine.
Do NOT use their reloading data as anything other than a general guide in developing starting loads!
There was a significant change in point of impact between my sabot loads and regular .308 ammo, it was definitely more than a couple of inches. That didn't bother me since the change was consistent and I'm used to making large sight adjustments when switching between regular and subsonic loads.
I pretty much gave up on the sabots in .308 Winchester because my Model 700 is HEAVY. I've also got a .257 Bob Ackley Improved that's way more accurate than any of my .308 sabot loads and far better for dual use as a varmint/big game rifle.
I plan on trying sabots in my new 300 Blackout one of these days.
