The key is to have everything in order. Passport, Match Invite or Hunting License, Import permit/permits and even hotel reservation confirmation.
Calvin
I agree... the paperwork is required in advance... the US laws require that... and you don't get that paperwork at the border...
I also believe the same US laws require paperwork in advance of arriving at the border with the intent to cross the border with firearms and/or ammo... and you don't get that paperwork at the border either...
I used to travel all the time with rifles, handguns, ammo to the US and back... with no paperwork other than an invite... but then the laws changed and a permit had to be applied for and obtained. It took a month or more to get it... That's US law... I believe it is still in effect...
It isn't as easy as some suggest to cross with firearms/ammo... at least legally according to US laws... and the US border patrol are the ones to watch out for...