Coach Dan John is one of the main people I look to for training information and inspiration for our workout programming. He answered an interesting question on his podcast, about heavy Kettlebells and if they are useful. You would think that there would be a pretty forthright answer to the question, but there isn't one. Take a few minutes to watch the video if you are interested in what he has to say about the subject. Then I'll give you my take on the subject as well.
Take a moment to digest what he said before you move forward to my thoughts on the subject.
We currently have over 160 kettlebells at the gym. They start at 08 kg (18 lbs) and go all the way up to 60 kg (132 lbs). The majority of the kettlebells fall between the 16 kg (35 lbs) and the 32 kg (70 lbs). This distribution pretty much reflects the utilization for both single and double Kettlebell use as well.
I'm not saying that the 60 kg Kettlebell doesn't get used, because it does. It's just that it's used by only one or two people, out of 40 or so. If we didn't have it, it would be missed, but it wouldn't be a devastating loss.
My experience working with Kettlebells over the last two-plus decades, is that people who get really heavy Kettlebells, meaning over 32 kg, aren't using them for more than one or two techniques. And, they are more than likely not being used in an efficient manner. I'm sure that this statement is going to upset a small subset of Kettlebell users out there, but I'm okay with that.
What do I mean by an "efficient manner"? It means that people are using heavy Kettlebells mostly for heavy Swings, which are Ballistic, and they end up being a Grind. It's impressive to see people "Swing" heavy Kettlebells, but they would actually get a lot more benefit from Swinging a lighter Kettlebell ballistically. Even if they are using them for Goblet Squats, which is an even fewer people who have the strength to hold it with two hands, they would be much better off using two Kettlebells.
Do you understand the distinction between a Ballistic and a Grind? If you do, then you'll understand that they both require a certain load criterion to make them effective.
The long and short of the story is: use Kettlebells for what they are designed for and you will get miraculous results. If you don't use it in the manner it was designed, you're going to spend a lot of money on something that is just going to gather dust in a corner somewhere.