Read the text at the link. What we have here is a bill by the Wyoming Congressional delegation to force the issue of carrying a concealed weapon in accordance with the laws of the state in which the National Park resides. It'll be interesting to see if the bill ever makes it anywhere in either chamber, considering who has the reigns of the runaway stage coach that is the US Congress.
I've said it before, and I'll say it again. If a state such as California doesn't allow carry of concealed weapons in a park (state, local, or otherwise) then carry won't happen in, say, Yosemite.
However, Wyoming and South Dakota, in particular, allow concealed carry in their parks. South Dakota just recently passed this important clarification 2 or 3 years ago. While Wyoming allows for carry in its parks, discharge of a firearm is a crime. (Although if it were a defensive gun usage or DGU, say to prevent a forcible felony like rape, I believe that would be OK by their standards.)
Bless Senators Barasso and Enzi and Congresswoman Lummis for bringing national park regulations into the modern era. 48 states allow some form of concealed carry (39 shall issue, 9 may issue, and 2 no issue, with DC recently being upgraded to may issue).
(h/t to Snowflakes in Hell for the link)
This is one bill that needs to see the light of day.
UPDATE: Kevin Baker of TSM pointed out that the actual number of shall issue states is not 39, but 37. Vermont has no requirement for a permit and Alaska does have a permit, but only for reciprocity with other states. Thanks!