| On Monday morning (05/03/21) I checked my baggage in at Spokane International airport. Alaska Airlines (ASA) accepted my checked baggage and TSA screened and accepted my baggage for airline transportation. One of these items was a box of factory sealed ammunition that weighed approximately 25 pounds. My baggage was transferred to another ASA airplane in Seattle and transported to Juneau where I had a three hour layover after which I would board another ASA flight to my final destination in Sitka. During the boarding process in Sitka, I was called to the ASA customer service desk in the departure lounge. Once at the customer service desk a rather rude customer service agent informed me that my ammunition would not be allowed to travel to Sitka. When I asked why, she stated that the box (baggage) "had the wrong markings on it". When I inquired as to what the wrong markings were, she couldn't give me an answer, stating only that an airline baggage handler had said that the markings were wrong. I then assured her that I was well aware of FAA, TSA, and ASA regulations regarding the transportation of ammunition and that my baggage met all of those requirements. About that time she started to become very rude and, with a raised voice, informed me that my baggage didn't meet the requirements. I then asked her to explain to me how it was that both the TSA agents and the ASA customer service agents in Spokane cleared my ammunition for transportation on ASA earlier the same day. She defiantly stated that the people in Spokane were wrong. Following that comment, she stated that I needed to pull my face mask up over my nose, which had slipped down during our conversation. Since the municipality of Juneau owns the airport, it really wasn't her place to try and assert authority over my mask. When questioned further, she stated that I was welcome to exit security, repackage my ammunition and then check it in again for transportation with ASA. I stated that since the flight was already boarding and there was only one flight a day to my residence, that was not a feasible option. After I boarded the plane I placed a call to someone in Juneau to attempt to pick up my ammunition so at least the ASA baggage handler wouldn't get to keep it. The most logical conclusion I can come to is that someone at ASA in Juneau wanted my ammunition and timed the notification to me that it wouldn't be allowed on the flight so that I wouldn't have time to deal with retrieving it. It would be nice if Alaska Air would compensate me for my troubles and $1,000 loss but I won't hold my breath. If they don't I will go out of my way to give my business to small regional airlines and other major airlines, even if they cost more!