Some of the larger online retailers, and by this I mean anyone from CTD to Amazon can and do adjust their online prices as often as every 15 minutes. There have been several news reports on this practice... in particular the mainstream Amazon.
What they do is adjust their prices based on information obtained with algorithmic data mining software... to be not too low, or two high. There's actually a company, you can become a member of, that searches using the same methods. Decide.com advises you to buy or wait based on their proprietary price and model predictions. At present however, Decide.com does not do firearms and firearms related items in their "Sporting Goods" category.
Shoulder Drive Nicholson Club