Indexing and Knurling Bullets

[ET1]

Some may question the validity of these 2-principals and will let the reader decide after reading what I express.


INDEXING
The principal here is getting the best 2-land coverage on each sabot petal. Consider this, the pressure from the lands is what provides the grip of the bullet through the sabot. This also suggests that only 50% of the bore provides sabot/bullet grip. I believe the reader knows where I’m going with this.
To simplify loading in the proper orientation I use a pop mark on the crown that allows me to quickly align the sabot. Just align a petal split to the pop mark and away I go.



KNURLING
So, what does knurling do? For me it produces a desired bore fit with a load resistance of 20lbs or slightly better. The best way I can describe the fit is one hand just doable or 2-hand with a palm saver is much easier. In case anyone is wondering how I get my load resistance measurement I made a little device working on the principle of spring compression.

Compact and works reasonably well.
Knurling provides a bullet surface that interlocks with the sabot. There can be no separate movement of bullet or sabot with the right compression fit. If you are already using a tight fit bullet/sabot load there may not be any real gain with knurling.


What I try to produce is a loading consistency and let the powder burn do the rest. Then it’s just being sure I’m on the sweet spot.

[diverduck]

Neat tool! Sounds very detailed. While I admit to loving to load for accuracy with my rifles, the muzzloader is like another rifled shotgun to me. I pop 2 triple 7's down the barrel and jam a bullet in. Groups still seem to hover around 1.5 inches at 100 depending on how still I can sit. Good enough for the girls I go with!

[ET1]

Hey Diverduck

If you are getting 1-1/2” group at a 100yds that’s still a respectable group. If you’re content with that, then don’t change anything. I’m one of those that has to explore boundaries to see what I can get for more accuracy with my SML.
Good hunting this season.