For years I've used chronographs in developing loads. I had one where you shot one shot thru a pair of wire mesh screens. The bullet broke one circuit to start the clock and the second to stop it. Then you had to replace the screens. I then had, I actually still have, an early Shooting Chrony. You shot thru cardboard panels with holes in them. Below those were photo sensors that once again started and stopped the clock. The readout was on the front of the unit. Then, a number of years ago, I upgraded to a Shooting Chrony Beta Master. The readout is connected by a cable to the unit and sits on the bench. In all cases these units were positioned about 15' in front of the bench. These units served me well but they have their down sides. First and foremost, you have to align the rifle, the chronograph and the target. this takes time and at a public range can tick some people off. Secondly, they are lighting sensitive. They do come with light diffusers but even with those, even a passing cloud can make a difference in the accuracy and consistency of the readout. Sometimes they will miss a reading or give a reading that is way out of line. Like everything else, new technology comes along. About four years ago, I purchased a Magnetospeed. This unit straps to barrel of the rifle and a wire runs to the readout with is right there on the bench. When a shot is fired, the blast starts the unit and it tracks the speed of the bullet as it passes over the "bayonet". As I shoot at a public, state operated range, the idea of not having to delay people while aligning the rifle, chronograph and target was a plus. However, this too has it's quirks. First is that after a few shots, you have to reposition the bayonet on the barrel as it has a tendency to slide. This is accentuated with heavy recoiling rifles. Often these create the need to reposition after every shot, and in some cases I've had it slide off the end of the barrel. Additionally, it can't readily be used on my mannlicher stocked .30/06. Another downside is that it can effect the point of impact. With the having to constantly reposition the bayonet, I found myself using the Chrony and only using the Magnetospeed if the range was extremely busy. Like I said, technology is always changing. Last year a few of the Lab Radar units started to show up at the range. Of course I had to try this out. So over this past winter I purchased one, along with a mounting base and rechargeable battery backup (A must, as this thing will eat AA batteries like candy!) Prior to my purchasing the Lab Radar, I read the reviews and everything I could about it. One issue people were complaining about was aiming the unit. They recommended taping a deprived .223 case in the top sighting groove. I've found this wholly unnecessary. I did find a few idiosyncrasies that must be dealt with. The first being that there is a setting for how far to the side of the unit the muzzle is. No matter what, I have to have the muzzle within 4-6". Also, the sensitivity setting needs to be se to the most sensitive. It took me about three trips to the range and a call to Lab Radar to get things right. Now it works like a charm. I've fired about 700 rounds past this thing and I've only had a few missed readings. It doesn't like the .17 Hornet. It only picked up four of ten shots. Muzzle brakes can cause some issues. Last week, I was shooting my .45/70 Contender handgun with a brake and it only recorded two out of twelve. Other than that, after the learning curve of the first two weeks, I show it only missing two readings due to the unit. I've missed a few because of my forgetting to rearm the unit after the unit timed out and unarmed itself. USER ERROR! Well I was at the range this week, working up a load for my .280 and just practicing with my .30/06, .223 and .416 Ruger and I got to thinking (It's very scary when I start to think): I wonder how the different chronographs would compare shot to shot. So I set everything up. I then proceeded to fire six rounds from each rifle across all three units simultaneously. There were a couple of glitches. First, the Chrony failed to measure one of the .416's and one .223. Additionally, one reading for the .30/06 was way out there (3452 fps... with a 180 gr bullet). Fortunately I had enough of the same ammo with me, that I just fired substitute rounds. The other was that, as I mentioned, the '06 has a mannlicher stock and due to the taper of the stock, I couldn't properly attach the Magnetospeed, so there was no data recorded. Below are the velocities recorded. Something of note is the .30/06 data. The Chony data is in line with what I obtained last year, prior to my Namibian safari. As I had a fair amount of loaded ammo, I used this during my first week with the Lab Radar. I got readings about 100 fps slower than the last year's Chrony readings. A second session with this load and this week's session confirmed the disparity between the Chrony and the Lab Radar. .280 REMINGTON / 160 GR SIERRA SBT HANDLOAD SHOT # CHRONY MAGNETOSPEED LAB RADAR 1 2602 2627 2624 2 2654 2648 2659 3 2662 2656 2644 4 2628 2648 2637 5 2640 2649 2636 6 2643 2640 2651 AVG 2638 2644 2641 .416 RUGER / 400 GR HORNADY DGX FACTORY LOAD SHOT# CHRONY MAGNETOSPEED LAB RADAR 1 2366 2385 2390 2 2354 2386 2391 3 2342 2411 2388 4 2358 2403 2383 5 2362 2392 2377 6 2356 2386 2386 AVG 2356 2393 2385 .223 REMINGTON / 60 GR NOSLER BT HANDLOAD SHOT# CHRONY MAGNETOSPEED LAB RADAR 1 3097 3103 3106 2 3073 3025 3068 3 3047 2999 3099 4 3079 3019 3078 5 3056 3011 3059 6 3088 3092 3071 AVG 3073 3041 3080 .30/06 / 180 GR BARNES TSX HANDLOAD SHOT # CHRONY MAGNETOSPEED LAB RADAR 1 2697 2587 2 2701 2572 3 2714 2556 4 2673 2571 5 2674 2568 6 2668 2584 AVG 2687 2573 With the exception of the .30/06, all three units were in relatively the same vicinity, velocity wise. I hope this info helps you make a more informed decision when choosing a chronograph.