Keep Flygon in, just in case someone DOES use it. If a counter exists hypothetically, mention it, because somebody, somewhere will probably have a FLygon in their team!
Flygon isn't a counter to sets with Sucker Punch, and sets without Sucker Punch lose to..., well, pretty much anything faster that isn't choice-locked into a resisted move. If we were going to list all of those, the analysis would be nothing but counters.
Plus, nobody uses Flygon.
Both will make setting up much easier, and Kirikizan can use Iron Head alongside Chople to survive Mach Punch and KO Roobushin with some previous damage (+2 does 76.4% - 90%) as well as survive some other fighting attacks.
I've run this, after someone was raving about it in an RMT. It just doesn't work very well.
Bisharp goes for the SD, and Conk comes in. Bad players will Mach Punch right there to go for the OHKO, hit the Chople Berry, and...Bisharp gets a +2 Iron Head in but it still doesn't OHKO. So they cripple each other and Conkeldurr has to switch out, best-case. However, most people expect a switch out and Drain Punch aiming for the switch, so their Conk takes a +2 Iron Head and wrecks Bisharp in reply, healing out of Sucker Punch range. This play was the most common one even before people knew I was running Chople; if Chople were published on a Smogon analysis, even fewer people would Mach Punch. It's surprising and unexpected when it works to KO a damaged Conkeldurr, so it
feels powerful. It just isn't winning many games, and it's quietly losing you many others because Bisharp is doing so much less damage to everyone else.
Besides Conkeldurr's Mach Punch, Chople Berry is pretty marginal. CS TTar Superpower does 80.2% - 94.6%; Superpower from mixed TTar would certainly be less, but mixed attackers can OHKO with Fire Blast (or Focus Punch) but can't take a boosted Iron Head anyway. CB Scizor OHKOs with Superpower straight through the Chople Berry. Even CS Scizor does 77.8% - 92.2%. Every Reuniclus EV spread from the analysis at least usually OHKOs with Focus Blast, and every Gengar certainly will. Every non-gimmick Focus Punch will OHKO through Chople; a Focus Punch from max attack adamant
Blissey would do 53.3% - 62.9%. Even goofy nonsense like CS Staraptor's Close Combat is doing 81.4% - 95.8% through Chople.
As for fighting types, forget it. CB Conkeldurr, Infernape, Blaziken, all three Musketeer legendaries, Mienshao, Sawk, Lucario, Toxicroak, and DD Scrafty take a boosted Sucker Punch or outspeed any other attack and OHKO even through Chople Berry. LO Bisharp is better at beating slower fighters, like Machamp, Throh, and Bulk Up Scrafty, because LO makes OHKOs with +2 Iron Head possible.
It's important to remember that Conkeldurr's Mach Punch is an anomaly. It's rare to see an unboosted 40 base power attack in this metagame, of any attack type. The only reason it's a threat to Bisharp unboosted is because Bisharp has a quad weakness and merely middling physical defense overall. Using an item which protects you from only one of two fighting attacks on one single Pokemon in a metagame full of threats to Bisharp is pure gimmick material.
tl;dr: It's an Electivire-tier noob trap that wins big against a misplay but doesn't work very well most of the time.
You Taunt non-attacking leads and force them to attack you, and Metal Burst regular attackers. With 130 Speed and 334 HP
I see a glaring issue right here. Taunting isn't going to do much good if Bisharp doesn't outspeed. Also, Conkeldurr (and Throh) will be slower despite the 0 speed IV, so Metal Burst would be ineffective except against Mach Punch.
Plus, on its best day, all it does is get one KO then get revenged by anything in the game.