Barrel wt vs barrel wt vs gun manufacture doesn't change bullet velocity in a given cartridge/Bullet weight Barrel length does! Sure some ammo velocity isn't consistant between rounds. And barrel lengths different than used in factory test will affect velocity, which also changes trajectory. I agree you have to shoot for yourself to zero,and see which ammo groups best in your firearm. I wasn't talking about accuracy test,it was cartridge performance specs.
after several phone calls i have made to both Hornady and Barnes. neither company tests with a complete rifle. They have "barrels" (35lb peices of steel) at different lengths and twist rates. both of which does effect trajectory. for example-- just talked to a Hornady rep on Friday. their 5.56 ammo is test fired through a 20" barrel with a 10:1 twist. My results with a 16" barrel with a 9:1 twist will be different, not sure on how much different but, it will be different. and even then my rifle might not like the ammo. still playing that game with my 25-06. hornady shoots well but am trying some different factory loads to see if anythings groups better.
Best way is just go shoot, put in the range time and maybe try some different bullet weights and see what shoots best.
You are right. I was just trying to give someone a way to look for info,and its a pissing contest on who knows more. Maybe the man didn't know about ballistic data. Its always a good place to start,it tells you cartridge performance at most useable ranges,then go get some rangetime and get familiar with gun and load. If someone can't understand ballistic data,then don't use it and say it is guestimates. Some people might not know about and it might be a big help to those interested.
I own several different loading manuals and they are just tools I use to put me in the ball park so to speak. most of the velocity#'s listed are not the same from mfg to mfg even when using the same amount of powder and type of primer it's just a value (using their weapon) if you want a closer/more accurate velocity reading youre gonna need a chronagraph and then those will differ slightly also. the books are just a starting point to give you an idea of what you may get. in the end the book isn't gonna pull the trigger, the shooter is. and I put more faith in what I see than what I read. I'm not saying the data is not required IT IS ESENTIAL, but it still needs to be tested and verified by actual shooting. and I'm getting too old for pissing contests.
