In my opinion they are not as useful as they should be.
1. In most cases multiple claymores are required for any effect.
2. Type of mission has to have the need where the deployment of a claymore could possibly be useful.
3. You have to know how and where to effectively deploy a single claymore and the terrain needs to be conducive for use in order to have any chance of success.
4. If you do get one to go off the spray pattern, effective range/penetration and the volume of bb's deployed are just not enough to get the desired result of wiping out a tight nit patrol. You will get the first person and maybe a second person but after that the spread isn't wide enough to target others and the first guys hit, block further bb's from hitting the people behind them. Brush penetration is negligible.
5. Some types require you to depress a button at the end of a 20-25ft cord for detonation. You might as well have just shot the person a bit earlier and been done with it. The tabs to place the claymore on the ground are flimsy for what you pay for, can break and can be difficult to utilize on varying terrain.
In short, they have the cool factor but I have rarely seen them used to any great effect. I have seen a guy or two get taken down by one, but that is very very rare.
