What topics in ballistics would you like to see explored?

[Laurie]

I don't know if you've ever heard of the following comments concerning the venerable .303 British: The .303, shot through the Enfields, displayed poor grouping characteristic at 100 yds, but when the shooting distance was extended to say, 500-1000yds, became much better performers. Also, by the same commenters, if rifles were zeroed at 100 yds, the groupings were substantially off to the right at those longer distances. The explanation then was given that the projectile had 'gotten to sleep'. [tazzman]

That's never been ascribed to the 'bullet going to sleep', well not at least on the east side of the Atlantic. It's a function of the non-rigid rear locking Enfield action causing 'positive compensation' that saw muzzle position at the time of bullet exit fortuitously 'compensate' for large differences in bullet barrel-time and hence MV variations in the as-issued arsenal .303 ball ammunition primarily used by British and British Commonwealth SR discipline shooters for generations. It substantially reduced on-target elevations, first showing at around 600 yards and becoming increasingly pronounced as you went by steps to 1,000. When Target Rifle using as issued 7.62 replaced .303 Service Rifle, it was practice amongst top shooters for maybe 10-15 years to have a Mauser system short-range rifle, but to retain an Enfield No.4 based job for the long-range 800 yards and up stages. That was ended with the Swing 4-lug and later Barnard etc 3-lug actions that were much better than either standard Mauser style twin-lug actions or the Enfield in coping with poor ammunition.

 

[Laurie]

Bryan, as a topic suggestgion, looking at recent bullet designs, there is considerable variation in bullet bearing surface length between models and between competitors in any calibre. People glibly talk about short bearing surfaces reducing pressures / friction and so short BSL models can be driven faster. Two out of three of Lapua's new Scenar L .308s though have long bearing surfaces by contemporary standards so far I can see (the 175 and 220gn models).

What factors influence / drive you as a designer in this regard? How does relative BSL affect both internal and external ballistics?

 

[CPorter]

Bullet lubrication with high speed thermographic analysis of barrel heat and the temperature of the engravings on the bullet as it exits the muzzle. Graphite, moly, tungsten disulphide and boron nitride as the major considerations.

A test of barrel pretreatment like lock-eze or the bullet lube in an alcohol solution for reducing cold bore group sizes.

I'd love to see a statistical comfirmation of Chris Long's optimal barrel time theory.

There have been some recent papers on annealing but nothing that I would call definitive. One did testing in microhardness and grain formation but did not get into final temperature, rate of rise, or dwell time and how they affect hardness & ductility. With induction heaters like the Annie and gas systems using propane or Mapp gas these are important differences.

 

[savagedasher]

Bullet lubrication with high speed thermographic analysis of barrel heat and the temperature of the engravings on the bullet as it exits the muzzle. Graphite, moly, tungsten disulphide and boron nitride as the major considerations.

A test of barrel pretreatment like lock-eze or the bullet lube in an alcohol solution for reducing cold bore group sizes.

I'd love to see a statistical comfirmation of Chris Long's optimal barrel time theory.

There have been some recent papers on annealing but nothing that I would call definitive. One did testing in microhardness and grain formation but did not get into final temperature, rate of rise, or dwell time and how they affect hardness & ductility. With induction heaters like the Annie and gas systems using propane or Mapp gas these are important differences.

;D With what your asking the winter shouldn't be a bore. ;D ;D ;D ;D Larry

 

[maxpower]

How about whether there is any difference in range contour effects on vertical dispersion. Say if you have a slow, heavy, high BC bullet with same wind ballistics as a lighter, faster bullet, and both with equal wind drift, will there be any difference in range effected vertical caused by quartering winds over woops and gullies.