Accuracy II

PP bullets are not as accurate as lubed grooved bullets. PP bullets are better hunting/killing bullets if made with BHn <10. I possess one of Col. Harrison's original experimental PP .30 cal. moulds. I could never find a method to make it shoot better than lubed grooved bullets. I would gladly paper patch for 1/10" group reduction even if it took 5 minutes each. Yes I am anal and competitive.

Ric, I and several others, one of whom I know personally, will respectfully disagree with your evaluation of the paper jacket.  Col. Harrison was a pioneer but didn't quite get it the mould or the technique right.   Many of us are guilty of universalizing our own experiences and stating them as the norm (to paraphrase Charles Graff), but I only discount those experiences if they are stated to prove a negative.  Just because you couldn't do it doesn't mean someone or many haven't done it quite well.

1, We are not going to get them by getting rid of smaller and smaller defects. We have been at it for a 100 years and have peaked out years ago. Throw away the magnifying glass.

2. Bore condition. Why are some of our best competitors bore cleaning after every relay?  Think about it.

3.  More of us, including me, should be looking into coatings.

John, finally a ray of light.  If you have to clean at all, or more than every 2-3 thousand rounds, my opinion is you're choosing the wrong components and that is detrimental to consistency.  If you want to be consistent you have to maintain a consistent bore condition, not one which goes from squeaky-clean to gradually accumulating fouling which degrades accuracy in 10 or even 50 shots.  Lube, powder, and alloy choices are how I have found to manage bore condition.  Coatings are not the only way to improve on the status of bore condition, dynamic alignment, and bore obturation (obturation in the technical sense, meaning "block" or "obstruct", not "bump up"), but some of the coatings can show great improvement (when fit and alloy are correct) with little effort or understanding, just follow some simple directions.

Those who are using liquid, tumble coatings in their quest for MATCH ACCURACY have me completely stumped.  Liquid Alox is an expedient for when you don't really care how it shoots or what condition the bore is in, just large-volume, low effort bangbangbangbang, like IPSC, or blasting cans.  One of the first things I learned about bullet lube, the hard way, is so-called "tumble" lubes are not the answer to rifle accuracy needs.

Someone is going to point out that it requires more than a BHN number to describe an alloy. I agree but it is an attribute than can be measured by most casters.

Jim

Very true, but that can be simplified too, at least in direction, not in explanation:  Make your hardness with antimony up to 2.5% or so, then heat treat beyond that to the level required for the pressure.  No more than one percent tin should ever be required, half a percent will do fine for everything I have ever needed.  If you have trouble casting a tin-starved, low-antimony alloy, then spend some time refining your technique.

This and similar advice has been given here many times, and usually is scoffed.  I'd like to see everyone do better, but none of you are going to get better unless you abandon the current dogma and begin to understand what you're doing wrong, why, and how to fix it.   Alloy choice, powder choice, bullet fit, and lube choice will be probably 90% of what gets you "there".  The rest is fine-tuning.

I'm sure a few members will be along shortly to demand 200 Gigabytes of witnessed, lab-condition test and shooting results to back up what I say, and discredit me on basis of association or character.  The truth is, no amount of data I provide will be good enough.  You have to do this for yourselves before it will be validated, and not enough is understood yet to do that because few if any are willing to actually try it, start gathering their own data points, and come back to ask questions.