Six Nations wrecking crew: Gray, Lawes, Launchbury, Gourdon, Watson, Tipuric - BBC Sport
From the hitmen to the tree fellers, Jeremy Guscott picks the best tacklers on show in the 2017 Six Nations. Join the debate and rank his choices yourself.
This weekend's Six Nations on the BBC Coverage: Wales v Ireland on BBC One, BBC Radio 5 live & BBC Radio Wales; England v Scotland on BBC Radio 5 live & BBC Radio Scotland. Live text online.

These are the tackling machines, the ravenous beasts who bring the opposition to ground time after time.

They range in style from tree fellers to hitmen to ball-and-all envelopers - but they all have one aim in common: to take their man down or out of the action.

They don't have to be forwards - as anyone who saw former England fly-half Jonny Wilkinson in action will attest - but it's no surprise my picks this year are forwards because that's where most of the bish bash goes on, close to the breakdown where the big men lurk.

This kid is a tackling machine who hardly ever misses his man - anyone carrying the ball into his channel is going down and he is so consistent that when he finally missed a tackle in this year's Six Nations it was newsworthy, as he didn't miss a single one in the 2016 tournament, making 58 with a 100% success rate.

So far this year, he's made a tournament-high 52 tackles - including a phenomenal 26 in the opening win over Ireland - but two missed attempts mean he 'only' has a 96% success rate.

He's not the biggest of hitters but he puts himself about to make the numbers and, still aged only 22, he has a long and potentially glorious future in the game ahead of him.

He has a well-deserved reputation for being a tree feller, a smash-and-wipe-out merchant who can wreak havoc on the opposition, but he's not the headless, full metal jacket type of player that some have claimed and is more controlled these days, which is great to see.

He's made 45 tackles so far with a 94% success rate and although he might be a touch behind Gray when it comes to consistency, he's certainly got the upper edge in explosive physicality.

Critics say he only levels half-backs, but how many other second rows have the speed to get out of the line and smash them, or cover across to lasso them after a 50-metre run? He can put anyone down when he times it well.

Another second row in the workhorse mould of Scotland's Gray, Launchbury has formed a superb locking partnership with Lawes for England this season - a remarkable illustration of their strength in depth, with fellow second rows Maro Itoje playing on the blind-side and George Kruis currently injured.

Despite being 6ft 5in and well over 18 stone he has unbelievable staying power, which all locks need these days.

He's made 46 tackles this season and although he may lack the sheer percussive impact of Lawes, the Wasps man brings a rumbustious presence to the heart of the England pack.

The France back row is not one of the game's glamour players, but in a struggling French team he brings a dogs of war spirit to their efforts.

He has a high work-rate and is a real nuisance of a player, shouldering a huge defensive burden to try to get France on the front foot again - he's the second-highest tackler in the tournament, with a solitary miss in 50 tackles.

Like Italy counterpart Maxime Mbanda, who has a similar attitude but misses the odd tackle in a way Gourdon does not, he is not the biggest of flankers. However, there is no doubting the size of his impact in 2017.

At 6ft 1in, Watson is another of the "smaller" players in this list - but another busy bee with a ferocious work ethic.

In Scotland's rearguard win against Ireland he made an astonishing 19 tackles in about 50 minutes of play - he was a human strimmer that day, chopping down men in green like blades of grass.

That performance alone was enough to catch everyone's eye and put him on the tackling map but he's continued in the same vein, having missed just one tackle all tournament.

He is one of the great footballing back rowers, but Tipuric is an amazing all-rounder, as he is proving this tournament with his tackling heroics.

As an open-side it is imperative he takes players out of the game and he does just that with his tackling excellence.

He leads the way for Wales with 43 tackles so far this tournament and has shown that he has the physicality to complement his skill set.

Who has Guscott missed out?

As always with these lists it's impossible to please everyone, but who do you insist should have definitely made the cut?

England flanker James Haskell might count himself unlucky not to have made the selection, and what about Scotland centre Alex Dunbar? Where's Jamie Heaslip? And no Alun Wyn Jones?

Use our interactive tool to rank Guscott's selections for yourselves, and join the debate below on who you think should be in the Six Nations wrecking crew.