Uhhh...I know what you were talking about with the 350 grippers. I actually had a typo and meant to write 400 instead of 300. I.E. if you want to be able to hold onto the deads you can do now.
Holding on to a bar while dl and trying to squeeze something shut is different.
Nope. Which means I guess I guess you see my point but I suppose I misunderstood your goals. You said you hoped it helped your deadlift forearms grow so I was going by that.
I thought you wanted to be able to hold your deads while growing your forearms. If you want to be able to close 350 more power to you I just misunderstood the intent of the question I guess. Just trying to help and say that while closing something is not the same as holding something, the fatigue and basic volumising of it is still cumulative, so you can overtrain your grip and then not be able to hold your deads. It's not the same but you still get tired from it. Yes, I have tried grippers. Not those same ones but very similar and this is the kind of thing I had to deal with when getting to excited with them. If you are doing any other grip work you might want to take it out at first and see how things go before adding stuff back in.
So you have to scedule and program it like anything else. I'm not saying it will happen but working up to the big grippers is a task in itself so if you are presently engaged in working up to holding on to the heavy deads it's just a warning is all. Just don't overdo it along with all the other stuff.
It's kind of the same thing as even though leg extensions do not help your squats all that much they still make your quads tired so if you want to squat big you don't want to do leg extensions all the time, unless, that is, having a record leg extension is more important to you
Good luck on it.