Bud I would agree with that as far as the mold choice but even that would require hands on tinkering in the shop to finalize the fit to bore. – Yes, the mold is only the beginning. I’ve got several custom molds that have taken the same amount of work to get repeatable results.
The bore rider is the simplest design (IMHO) and even that has to be fitted to the bore either with beagling or choice of alloy. – I’ll lap a mold as a last resort.
But match reports are a great place to start for mold selection. – You have to start somewhere, set a baseline and keep good records of each change.
Powder selection is great topic and I'll start a thread specific to powder using your post if you don't mind. – Do it.
BTW did you mean N-135 or N-335 in your post? – N-135
As a disclaimer, there are many others that shoot for accuracy that do not compete. – Yes, one of the choices of accepting the Boeing offer and moving here was the opportunity to shoot.
I fully respect their knowledge and skill. – Yes, I know several people who do this. Most are prairie dog shooters seeking another hundred years for the next season.
But match reports are the only source those that do not decades of individual experience in cast accuracy. – Very useful.
And if it’s shot and measured in a registered match its solid information (cast competitors don't lie about their equipment list like those jacketed BR shooters). – I’ve shot jacketed and found the same thought.
At this point in my learning curve, I respectably disagree with you about seating depth. – Disagreement leads to more experimentation and better collective knowledge.
I qualify that comment by saying that although I've cast for almost 30 years, and it’s only been in the past year that I tried to keep them all going through the same hole. – I started on this voyage three decades ago as the match concentration forced me to forget work problems. For five hours at a Saturday morning match, the concentration took away the work week and then I have the rest of Saturday and Sunday to enjoy.,
Let me put it to you this way; I think seating depth is to jacketed accuracy as bullet fit is to cast. – Yes, I have the same thought.
And right behind bullet fit to throat for cast accuracy I would put powder choice. – I don’t think powder is important with reduced loads. I’ve found a rule with jacketed; when the load starts smoking at the muzzle, it is at peak efficiency. Even if not a maximum load, I quit at that point.
And for clarification could you explain "witness mark at .050". – The mark of the land on the bullet measuring .050 in length. This does not have to be even as the leade and the bullet can vary enough to not be uniform.
I came from a jacketed accuracy world where the key words were kissing and jam. – Yes, same thought.
And then we speak about thousands of an inch off of jam. – Yes, my gunsmith is a jacketed long range specialist, and we have to go through a definition of terms each time I drop a rifle off.
So, with only one powder and one mold where do you start your seating depth for bore riders? – Slight witness mark on the nose. The current move to the Remington style boltface is like putting metal rod centered the boltface and a live center on the tailstock. The boltface holds the cartridge centered in contrast to the claw extractor letting the cartridge drop in the bottom on the chamber. The pressure on the bullet nose aligns it in the bore. Keep good records of temperature, alloy and casting temperature to see how the bullet fits.
Spitzers? I kind of made a big deal about where the gas check sits in the case because I think it’s important. – I do too. Empirical research to this date, but I have a 7mm BR and a 7mm-08 I want to do a structured study on. The SAECO 160 grain mold and the RCBS 168 grain mold together.
But what I think and what someone with 20 years of cast accuracy knows is two different things. – I am never sure what I know, I am restructuring my testing methodology in this coming 7mm endeavor. When you think you have the right answer, go back to see if you have the right question.
Farm boy from Illinois, living in the magical Pacific Northwest