Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Big 5 Sporting Goods (NASDAQ:BGFV) were giving investors a high-five today after shares jumped as much as 16%, following a strong earnings report.

So what: The Western-U.S. sporting goods chain delivered an EPS of $0.34 on expectations of $0.20, and also posted an impressive same-store sales increase of 10.5%. Management said the jump in profits reflected "enhancements to our merchandise and marketing programs," as well as "an increase in demand for firearms and ammunition and more favorable weather conditions."

Now what: Management also said that positive sales trends have continued into the second quarter; but, of the three causes cited above, only one is sustainable and within the company's control. We've seen similar retailers post strong gun sales recently. Cabela's, (NYSE:CAB), which provides numbers on firearms sales -- unlike Big 5 -- said that half of its same-store sales increase came from that segment, so it's not unreasonable to conclude the same for Big 5. However, with the recent defeat of a gun bill in the Senate, the cause for that increase -- fear of increased gun regulation -- seems to have been removed. Considering this, now seems like a good time to sell, especially with shares having tripled in the last year.

Get more on Big 5. Add the company to your Watchlist here.

Fool contributor Jeremy Bowman has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.