Advice - Dog keeps getting dominant with puppies

[MaxMX5]

Hello,
I have an 18 month old Parsons Jack Russell who is male and has been neutered. We have had him since April this year after re homing him due to his previous owner becoming ill. At home he is a very well behaved dog and knows his place within our home however when out on walks if he meets a puppy, regardless of the size of it he try's to dominate it and pin it to the floor.

He only does this with puppies, with all other dogs he plays nicely.
Does anyone have any suggestions as to why he behaves like this and what we can do to stop it?
We asked the trainer who runs our weekly training classes why and she said that he will probably grow out of it but I am fed up of having to put him on the lead every time we see another dog encase its a puppy. That and it's not nice for the puppy he meets or the other dog owner.

Many Thanks

[Jasandjules]

You can let him meet my puppy if you like. Once he's been put in his place he may stop

Is there any pattern? Is it only male puppies he does this to?

[MaxMX5]

Not really, he will do it to female puppies too, but it does seem that he finds males more often. He has been put in his place by older more dominant dogs before but it doesn't deter him when he meets others.

[rambo19]

My JRT is the other way round, fine with puppies but wants to dominate all other dogs!!!
JRT's are very very pig headed, thats for sure!

[AdiT]

A Cocker used to do this to my Weim' for 6 months... he returned the favour for 18 months once he was bigger. They're fine together now.