The conjunction particle ものなら is used after the potential form of a verb to introduce a hypothetical situation. This grammar pattern implies that condition (A) is highly unlikely or impossible, but if it were to happen, then (B) would be the result. It can be translated as 'if one could (A), then (B)' or 'if (A) were even possible, then (B)'.

Grammatically, ものなら is a fusion of the noun もの (thing; matter) and なら, the hypothetical form of the copula だ. This combination frames the preceding clause as 'if (A) were a thing that could happen, then (B)'.

• あのチームに勝(か)てるものなら、勝(か)ってみろ。
  If you think you can beat that team, then go ahead and try.
• 買(か)えるものならすぐにでも買(か)いたいですが、高(たか)すぎて無理(むり)です。
  If I could buy it, I'd want to buy it right away, but it's too expensive and impossible.

Since ものなら often presents a scenario the speaker wishes were true, the second part of the sentence commonly includes expressions like てみる (to try) or てみたい (want to try). To further emphasize the hypothetical nature of the statement, もし may be added to the beginning.

• もし僕(ぼく)よりおいしく作(つく)れるものなら、あなたが作(つく)ってみてよ。
  If you can make it tastier than me, then you should try making it.
• もし過去(かこ)に戻(もど)れるものなら、子供(こども)の時(とき)に戻(もど)ってみたい。
  If it were possible to go back to the past, I'd like to try going back to when I was a child.

The use of てみる often carries a challenging or critical tone, suggesting 'if you really think you can do (A), then prove it'. On the other hand, てみたい expresses a personal desire or longing, conveying 'if only I could do (A), I would love to'.

Although it is not an absolute rule, it is very common for the verb in the first clause (A) to be repeated in the second clause (B), especially when expressing a strong personal wish to do that action.