" In my Hornady manual, I have a COL for all their bullets a as well as a Max COL for .243 win. I do not have a Speer manual and was hoping someone here could help out ... Please."
Okay, got a better handle on your problem now. Velocity plus rifling twist rate determines the fired bullet spin rate. Long, heavy (for caliber) bullets have to spin pretty fast to stabilize. Your barrel can't produce a lot of velocity with a cartridge that large so either you must have a faster than normal twist or use lighter bullets; with a 1:10 twist and the short barrel you do need to use short, light bullets that are easier to stabilize. I'd bet you can do better with bullets in the 60-75 gr. range.
OAL is a big bugaboo for noobs, and considering a lot of the "helpful" posts I see on the web, that's understandable. Fact is, book OAL is only what the book makers used to develop their data. It's NOT a "law" to be slavishly followed or you will die, it's only a good starting point! No matter the weapon, if the length is such that the bullet doesn't jam into the lands and the load is developed at that length and it feeds and chambers reliabily, it's good. That's it.
In some 45+ years of loading for many different rifles and handguns I am yet to even look at a book OAL spec. It seems to me that their OAL suggestions have caused much more confusion than they cure. In my early days few data sources even suggested an OAL. And some very good current reloading books and data sources still don't!
Something for you to understand about book data in general: no component change has nearly as much effect on a book load as the weapon it's fired in! Thus, all reloading info is generic by bullet weight and powder type so the source matters little if it's legitimate. ONE RULE, and only one rule, takes care of everything needed for safety; you may mix bullet type/brands, OAL, powder lots, primer and case brand, etc, as you wish IF you "Start low and only work up to book max if no earlier pressure signs appear." If you see pressure signs you've gone much too far, back off a bit. The defination of what "a bit" is varies by case volume.
