Some 8mm blanks (German army issue, for example) used light, hollow wooden bullets. Are those the ones you're referring to? The purpose was for use in machine guns without the need for feedway spacers. But they still needed blank firing adapters, to function the guns and to shred the wooden bullets.
If you fire a wooden-bulleted blank without a shredder, you better be sure there's nobody / nothing you want to destroy in front of you. The issue is not the barrel being subjected to force (it isn't) but the fact that you're actually shooting a projectile.