If you're curious about velocity, you can pick up an inexpensive unit from Shooting Chrony. They're not known for perfection, but all you really need to use it for is to give you a "ball park" idea of trajectory.
There are other ways, however, to establish trajectory--and velocity. Simply shooting at a large target in the distance, or at a rock on a bank at, say, 500 yards, will give you the amount of drop your bullet is actually experiencing from that 100 yard zero. In other words, if you shoot at a baseball sized rock on a hillside at 500 yards, and the bullet splashes dirt four feet down the bank, you've got a ball park idea right there. Four feet at 500 yards would be about (about /ubbthreads/images/graemlins/wink.gif ) ten MOA. Dial the scope up 10 MOA (forty clicks on most scopes) and try another shot.
Now you know your bullet, which has a BC of .365 say, is dropping 10 MOA at 500 yards. You can calculate velocity from there.
Targets...
Targets are the final arbiter of what a load is doing. No matter how good, or how bad the chronograph numbers look, the target has the last word--at 100 yards to 1000 yards, between and beyond.
Developing a load to reach a specific velocity can often lead you away from good accuracy. You've got to let the components (bullet, powder, etc.) tell you where they want to group, then you must accept that velocity.
If you're working with a healthy charge (near the max in the loading manual) your velocity is going to be somewhere within ten percent of the numbers shown
in most cases. This should be generally true for barrels within two inches of the test barrel. So if Sierra got 2650 fps with a 180 grain Gameking and so much IMR 4064 in a .308 with a 22" barrel, your 24" barrel should be very close to that figure.
In my opinion, you really shouldn't even get curious about velocity until you find the powder combination that works properly. Some folks shoot strings of shots across a chronograph until they find a tight extreme spread. Sometimes this works, but often it will not. Depending on your seating depth, neck tension, etc., a particular recipe can look tight on the numbers one day, and sloppy the next. The OCW method
www.clik.to/optimalchargeweight will get you to a solid performing load in as few as twenty shots--without any help (or better put, distraction) from a chronograph.
So again, it is best to let the paper tell you what's working and what isn't. Think about it: If you're shooting 1/2 MOA groups at the longest range at which you hunt, do you really care what the chronograph is saying about SD and ES? And conversely, if your groups are all to hell at 1K and nothing you do seems to tighten them, does it matter that the ES looks good?
The Shooting Chrony which can be had for under 75 dollars works just fine, and is easy to set up. It'll tell you about how fast your bullets are going, and the targets will tell you the rest. Some of the F-1 Shooting Chrony models tend to like a calibration shot fired across them before you begin recording results. The Chrony folks actually just recommend firing a rubber band across the unit to let it get acclimated to the light conditions.
Use my OCW load development method (shameless plug) /ubbthreads/images/graemlins/laugh.gif and you'll get where you need to be. Once you've identified the OCW then you can chronograph that load recipe so you'll have a rough idea of trajectory and energy. You'll need the chronograph for about five minutes while you put a half dozen shots or so across it--then you'll be done with it. So I wouldn't invest in an expensive unit. You need to let the targets tell you how you're doing. All you need a chronograph for is a short cut to
approximate velocity.
Dan
