[jmr40]

Unless you're content to use only beginning or mid level loads a chronograph is pretty important. Loading without one is like driving a car without a speedometer, only a warning light that comes on at 95 mph.

I've seen enough testing to conclude that the $100 units are as accurate as the units in 4 figures. The high end versions will work in conditions where the cheaper units won't work, but the speeds the inexpensive versions show are usually within 10-20 fps of what the expensive units show. But under certain conditions the cheap units may not work at all, or you get nonsensical readings which are obviously wrong. I find any of the $100 units are good enough for me. If they don't work under certain conditions I'll just try again another day.

If you look at a book load showing 60 gr of powder should yield 3000 fps with a 150 gr bullet as the max load, then 3000 fps is the important number, not the 60 gr of powder. Without a chronograph most people keep adding powder and comparing group sizes while looking for traditional pressure signs. The problem with that is that traditional pressure signs don't show up until you reach 70,000 PSI, well over where you should be.

Without a chronograph you might incorrectly conclude that your 60 gr load is perfectly safe since it is showing no pressure signs. You could be shooting 3150 fps with 60 grains and still not be showing pressure signs. But you're certainly over pressure.

By using a chronograph you can monitor muzzle velocity as you work up your load. When you start getting close to 3000 fps you are approaching a max load. You may find that some combo's of rifle, brass, primer, and bullet will reach 3000 fps with only 57-58 gr of powder. That is where you stop adding powder.

In other cases you may find that 60 gr of powder is only getting you 2900 fps with some rifles. Technically it would be safe to keep adding powder over the book max of 60 gr and it would be safe in THAT rifle. I strongly advise against this because those loads could end up in another rifle where they could be dangerous. You're just going to have to accept that 2900 fps is all that rifle is going to do with that powder and bullet.

I don't worry so much about the exact speeds I'm getting. Some people try to use them with online ballistics programs to calculate drops. But those numbers are only good enough to get you close, you still have to actually shoot at those ranges and see what happens.

You have to also consider barrel length. If the load data is for a 24" barrel, and you have a 22" barrel then I'd consider 25-50 fps less than 3000 fps as max in that rifle.

Once I'm satisfied that a certain load isn't going to be over pressure I may tweak the load some by reducing powder to see if accuracy improves.