Jim101,
The 22 "Long" used the 22lr case and a shorter, lighter bullet that the LR. The only "Longs" still in production are the CB Longs by CCI, to the best of my knowledge. You must be using the Aguila "Super Colibri". These are propelled by the priming compound only. Give the CCI "CBs" a try. They come in the short and long version. These are more powerful than the primer powered rounds, but less so than the regular 22 rimfires.
Savage