Barking & Growling

My GS will be 6months in a week. I started him at a very young age to train him for obiences. To this day he is very good and does what you say 90% of the time (still a pup)... I usually go powerwalking with him and he just trots along. For the pass few weeks I notice he was like not listening anymore so I went out for my 4k walk but to train him again so he doesnt forget. He's a good puppy. Sits, stays, heels, etc etc etc... And yes, one problem with him he barks and growls at people or dogs or cats whatever he hears or sees. It's not a on going bark either. More of a protective bark and growling. It is really getting out of control now. And believe me we did (and still doing) everything we can to make him stop. But seems to go in one ear comes out the other. Hopefully its a phase but we all know dogs. Give them an inch they take a foot. He looks out the window he will bark at people walking by with or without dogs. We stand up beside him to remove him and hush him, say firmly NO, change his mind, or put your hand as a claw gesture and tap on the side of his cheeks...anyhow whatever we do or say, he just doesnt care. We will tell him NO he moves away from the window goes to his bed and starts to growl instead of barking cause we just told him NO Barking. We always use the word barking so he knows the difference between what the NO will be for. When I walk him he wont bark or growl at everyone just whom he feels like. If the person or if there are more than one like a bunch of kids playing outside they make noise they will bark or growl. Eats his bone, plays with a toy, hears the birds outside (less now) he will growl. When i went out yesterday for his walk he came face to face with a family with little 3 kids age from 3-7. It was the first time he was close and come to think of it he meets children. We got him late Nov. so now that its spring he walks more and sees more. We go to the park very often and loves it and plays all the time...good friendly pup..

Anyhow, people will say he's protecting his land or us. Well I dont think so. I think its developing into a bad habit. I was thinking of a e-collar or training collar only when I take him out for a walk or when we are in the house so when he goes to the window we would be there to see what he does and then we can tell him again NO BARKING. Eventually he will get the message. Soon he will be going outside for the first time in the backyard. I can imagine him barking at the kids in the other yards etc, etc.

If any of you guys tried something else than a collar by all means let me know. And yes I tried changing his mind like telling him to sit, or down or whatever even treats. NOPE still doesnt care. You know what he reminds me of? like when you punish a child and the child turns around mumbling while he's walking away. My GS does that. Barks, you say NO and he growls while walking aways. I know sounds funny but after a while hes not.

thanks for your inputs