Bullet/Sabot indexing

Would like to know how this is done and its purpose. Does this increase accuracy? Is bullet/sabot indexed to the grooves in the barrel rifling?

Most sabots have 4 petals. Many barrels are 8 land but there are quite a few that are not such as White rifles and Pedersoli.

Indexing=2 lands per petal.

IMO indexing wont turn a bad group into a good group. It may turn a good group into a very good group though.

I've actually never done it. Interestingly, every time someone brings this up I tell myself I'm gonna start doing it, yet I always forget to when I shoot. :d'oh!: I'm sure once I actually start, then it will start to become a habit.

It may or may not make much difference, but I don't think it can hurt at all. Doing things consistently are usually always a good thing.

I started doing it recently, and Im trying to make it a habit. Kind of on the "It cant hurt" mentality, consistency IS key. BUT I cant truthfully say that I have noticed a difference yet. Basically just starting a sabot to the same way in the bore, trying not to overlap a groove with a slit

You can see the rifling marks here. The lands are slightly off on this one. I use to index a petal with the front sight but now turn the sabot slightly counterclockwise so the lands are more even across the sabot petal.

I always index. Can't hurt. I also always knurl the bullet. I think it cuts down on unexplained flyers.

On my McRem, I marked two lands on the crown to make it easier to index.

I am about like the rest, I cannot say it has helped but it certainly has not hurt so I do it just for that reason and for loading consistency.

While I am new to the whole MZ thing, I seriously doubt that aligning a plastic sabot on the lands will have any effect, what-so-ever. The pressures and speed happening in that barrel will quite likely over-ride your best efforts.
The plastic is going to "find it's groove" as soon as it contacts resistance, and then act accordingly.
I personally think that, scientifically, the tighter the fit of sabot to bore, the more influence the rifling's and lands will have. With-in reason, of course.
It simply makes sense that a loose fit is probably going to allow some "slippage", if you will.
A snug, (NOT over-tight), fit will impart a truer spin on the bullet after it leaves the sabot. We are talking thousandths of an inch, here.
After all, when we rely on a piece of plastic that is intended to be discarded after leaving the muzzle to import the spin on the bullet, under tremendous speed and pressure, well, let the imagination run wild, but close contact between the two seems logical, to me.
I am currently under the assumption that that is one reason I, as a total new-be, am able to achieve pretty good groups with-out much experimenting. Granted, I have been well-guided from the get-go. But so far, snug, not super-tight, loads, with 100 grains of Bh209, have been stellar.
My thanks to Sqezer and Ron. They have made my journey so enjoyable, and my "what the hell" short!

Consistency and repeatability is the key precision shooting.
I believe sabot indexing makes a definite difference positive.

It seems to me that when four of your lands are perfectly aligned with the slots in a sabot the loading pressure is less.
So I mark a groove on the end of my barrel with a marker and align a slot with the groove when loading.
I personally think this helps with accuracy. Have you ever thought that the last bullet-sabot loaded really easy and the
next time they load like normal? Often that shot will be out of the group.

My initial thoughts were the same as alaska's. I couldn't see how it would make a difference. I guess I will try it both ways and see. If I find that it doesn't matter I'm sure I will give it up. To me it wouldn't make any sense to do it if it doesn't matter accuracy wise.

Having never looked closely at the rifling in a barrel I assumed the lands would be wider than the grooves. I see it is the other way around. If you align so that there are two lands on each petal with a groove in the middle would it than be the same on all petals? In other words a groove would also end up lining up with the slots between each petal?

What makes sense to me is to try as much as possible to be consistent when loading a rifle. Consistent in everything done i.e measuring the powder, seating the bullet, and locating the sabot. Consistent.