Minimum bullet/neck engagement?

[M1A1ABRAMS]

I try for a caliber length of bearing surface in the neck of the brass, so maybe .250-300" in a 7mm and .275-.325" in a 30 cal. With that said I will go more or less depending on what I need to do. If it has to mag feed and I have a short mag box I will stuff a bullet well down into the powder space. If I have a long mag box and I need to get close to the lands to get it to shoot the way I want I will go as low as 1/2 caliber of bearing surface in the neck. If it gets less than that I will try to find a point with a long jump that gets the accuracy back. Lately I have been setting everything up with a long jump, I have had some loads in the past just hammer 10 thou off the lands but if they are 5 or 15 off the lands accuracy falls off quickly. When I can get a load to hammer with a jump of 40-120 thou it seems in my limited samples that the window is much much wider, sometimes over 20 thou without any meaningful difference in accuracy. I load on the close end and let throat erosion take me through the window with no real decline in accuracy. Lots less fussing with loading and keeping an eye on throat

You may find interesting.

 

[TX Badger]

Here's something to chew on.

Thinking Outside the Box — Stan Ware’s Wicked No-Neck Wolfpup « Daily Bulletin

Think you need a relatively long case-neck for good accuracy? Think again. Stan Ware broke all the rules with his radical Wolfpup cartridge, proving that a near-no-neck design can deliver match-winning accuracy. Read on to learn how the Wolfpup works... <img class=alignright...

bulletin.accurateshooter.com

 

[RidgeTop]

.001 is o.k. and all you need, .002 is what I would call max. For special situations like crimps and bullet seating depth or cannelure may require different bullet hold.