The HPA is a much bigger "if/probably won't happen" than a when. I don't foresee it ever making it out of subcommittee, much less committee, and even then having enough votes. And certainly don't expect Congressmen to be clamoring to get on board what could be seen as a controversial bill as we enter primary season. Don't be drinking the koolaid Josh Waldron is handing out about it having a chance.
Not trying to be a Debby-downer, just trying to give you a realistic view. If you're contemplating more suppressors, the best advice is to go ahead and act as if you have never heard of the HPA because if you are waiting on it, you will probably be waiting forever.