Actually, there's more to it. They did more than modify an A record. They up and changed name servers.
The old record has a current TTL of about 17 hours, according to my ISP's name server. It's not my ISP's fault, as gunsamerica suggests. It's theirs. The TTL on their old zone file was waaaaaay too long (over two days, I think). My ISP's name server is faithfully doing what it was told, i.e. "Don't resolve this address again for another 17 hours". My name server had never previously resolved gunsamerica.com, so it looked it had no erroneous cache to refer to. It had to do a new lookup (root NS, then authoritive server for domain, etc).
Whoever is responsible for managing DNS at gunsamerica.com (even if they farmed it out) is a fucking moron.
[root@eagle named]$ dig @72.11.0.21 gunsamerica.com
; <<>> DiG 9.2.5 <<>> @72.11.0.21 gunsamerica.com
; (1 server found)
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 54262
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 1
;; QUESTION SECTION:
;gunsamerica.com. IN A
;; ANSWER SECTION:
gunsamerica.com. 61907 IN A 69.25.207.216
;; AUTHORITY SECTION:
gunsamerica.com. 155912 IN NS ns2.servercity.com.
gunsamerica.com. 155912 IN NS ns5.servercity.com.
gunsamerica.com. 155912 IN NS ns.servercity.com.
;; ADDITIONAL SECTION:
ns5.servercity.com. 53831 IN A 69.25.207.4
;; Query time: 67 msec
;; SERVER: 72.11.0.21#53(72.11.0.21)
;; WHEN: Tue Feb 28 21:30:59 2006
;; MSG SIZE rcvd: 129
[root@eagle named]#
As you can see, querying my ISP's name server shows the old IP address AND the old authorative name servers for gunsamerica.co. My ISP's name server is doing is exactly what it was told to do.