Blue Dot loads are the ONLY loads that I have ever shot that exceeded or even met the velocities published in manuals. I think that is why one sees a reduction in performance in a lot of modern manuals. Hard to give out data when so many folks out there can cehck it whenever they want to.
That said I think we all (YES that includes me) strive for the extra 100-200 fps that is relatively unimportant in the overall scheme of things!

I am not a pro but I trust my chronograph more than I trust loading manuals. Every gun is different and what is maximum in one may not be warm in another. Some times my loads are very close to book loads and other times are in another time zone. Lately I've been working on a 165 grain bullet load for my .308 Remington 7 rifle using IMR4064 powder. I consulted several manuals for a starting point and began my loads with 42.5 grains. The one manual said I should get around 2600 fps from that charge. My chrony averaged 2280. I did work up loads that got to 2700 fps with out excessive pressure signs but the charges barely fit in the case and exceed anything published by a full 3 grains. But theses are only safe in _my_ rifle and of course I will use a lighter charge with better accuracy for a hunting load. In another case, pressure sign and velocity showed my maximum to be more than 10% below published data. I believe the chronograph is a wonder tool for getting the most out of your guns. I don't think I'll ever develop another load without it.

The barrel is not the only thing that effects MV, the chamber has a large influance also. I recently had a oversize chamber and throat removed from my barrel, which took a inch off the length, MV went UP by 225fps average even though the barrel was now a inch shorter (same lot of reloads & factory used in both tests), and group size dropped from 2MOA to 1/2 MOA (all due to the chamber).

What you are seeing is normal. Published velocities are always higher...it's called "marketing"...

I just tried out my new ProChrono digital chronograph, and love this new toy! I was just curious as to how accurate most chronographs are. A moderate load in my .280 was a full 250 fps below the book, and my .243 winchester 100 grain speer is only about 2675 fps when I thought it would be closer to 2850. Since I am new to chronographing, is what I'm seeing normal? I have heard there are differnces between test barrels and most hunting ones, but I thought the same barrel length would be closer than that. I am just a bit concerned, since it is quite warm now, and I would expect these loads to be even slower under hunting conditions (15 - 30 degrees F). If it gets much slower, my .243 will be lagging behind my old 32 win. special!

Any insight from you pro's using chronographs would be appreciated.

Jasper243

now you should test powders at different temperatures. you'll be surprised at how much velocity you lose when the temperature drops. i am now using the hodgdon "extreme" line of powders for this very reason.

Post deleted by 243winxb

Yep, I expect it. I know there will be a drop from now with the temperatures in the mid 80's to typical hunting season numbers that will be in the 30's. That is part of the reason I wanted to get the velocity up. As long as the accuracy remains (it does) and the numbers are reasonable, I'll stick with this combo. I do use some of the Extreme powders in other calibers and loads though. I wonder if I could get a federal grant to study the issue. It would take lots of time and money shooting hundreds of firearms and mountains of ammo to get to the bottom of things. It would be a tough job but I think I could get some people to help out on it.