Pure piospam involves only spamming pioneers. This is different to a support strat where your force is primarily pioneers + a few support weapons, since they benefit from the same vet. Piospam is pretty crap against anyone but Brits since their soldier armour is weak against flamethrowers and they do relatively little damage to elite armour, which vet 2 pios gain. Properly played piospam, transitioning to grenspam, is actually impossible for a Brit to beat on most 1v1 maps without using BiB.
Basically, only build pioneers for the first part of the game (no WQ). Use these to cap out the map very quickly and build OPs on your resource points nice and early. Then get kampkraft and vet 2 on them as fast as possible and get flamers. From there, just blob up and roast his blob. If by some miracle he hangs on you can easily move into grenspam and have loads of OPs to spam shreks and firestorm.
