12 new stores since July 31, 2021. Our fishing, camping, optics, electronics and accessories and footwear categories saw decreases of $7.7 million, $5.1 million, $4.2 million and $0.6 million, respectively, in the second quarter of fiscal year 2022 compared to the comparable 13-week period of fiscal year 2021. Within the hunting and shooting department, our firearm category saw a decrease of $3.0 million or 4.2%, while our ammunition category saw an increase of $2.9 million or 5.6% in the second quarter of fiscal year 2022 compared to the comparable 13-week period of fiscal year 2021. The decrease seen in the firearm category is primarily due to the impact of consumer inflationary pressures and recessionary concerns, partially offset by the opening of 12 new stores since July 31, 2021. The increase in the ammunition category is due to a decrease in supply chain disruptions in this category as well as the opening of 12 new stores since July 31, 2021.
With respect to same store sales, during the 13 weeks ended July 30, 2022, our fishing, optics, electronics and accessories, camping, footwear, hunting and shooting and apparel departments saw decreases of 18.5%, 18.1%, 13.5%, 7.1%, 6.1% and 1.4%, respectively, as we began to see the impact of consumer inflationary pressures and recessionary concerns. As of July 30, 2022, we had 114 stores included in our same store sales calculation.
Gross Profit. Gross profit decreased to $117.5 million during the 13 weeks ended July 30, 2022 compared to $120.1 million for the corresponding period of fiscal year 2021. As a percentage of net sales, gross profit increased to 33.5% for the 13 weeks ended July 30, 2022, compared to 33.2% for the corresponding period of fiscal year 2021 primarily driven by increased product margins and favorable shipping, freight and logistical expenses during the period compared to the prior year as we slowed inventory receipts in response to consumer demand. These increases were partially offset by unfavorable product mix.
Selling, General, and Administrative Expenses. Selling, general, and administrative expenses increased by $1.2 million, or 1.2%, to $97.0 million during the 13 weeks ended July 30, 2022 from $95.9 million for the comparable 13-week period of fiscal year 2021. This increase was primarily due to an increase in other selling, general and administrative expenses of $2.5 million, which was largely the result of a return to pre-pandemic levels of marketing activities compared to the comparable 13-week period of fiscal 2021. We also saw increases in depreciation, rent and management recruiting expenses of $1.4 million, $1.3 million, and $0.7 million, respectively, during the 13 weeks ended July 30, 2022 primarily related to the opening of 12 new stores since July 31, 2021 and the recruiting and hiring of key senior managers. These increases were offset by a decrease in acquisition costs of $2.5 million due to the terminated merger with Great Outdoors Group, a decrease in payroll expense of $1.7 million primarily due to store operational efficiencies and by pre-opening expenses of $0.6 million due to the timing of opening new stores. As a percentage of net sales, selling, general, and administrative expenses increased to 27.6% of net sales in the second quarter of fiscal year 2022, compared to 26.5% of net sales in the second quarter of fiscal year 2021, due to the same reasons disclosed for the increase in selling, general, and administrative expenses.
Interest Expense. Interest expense increased by $0.5 million, or 166.7%, to $0.8 million during the 13 weeks ended July 30, 2022 from $0.3 million for the comparable 13-week period of fiscal year 2021. Interest expense increased primarily as a result of increased borrowings and higher interest rates on our revolving credit facility during the second quarter of fiscal year 2022 compared to the second quarter of fiscal year 2021.
Income Taxes. We recognized income tax expense of $5.1 million during the 13 weeks ended July 30, 2022 compared to an income tax expense of $6.2 million during the comparable 13-week period of fiscal year 2021. Our effective tax rates for the 13 weeks ended July 30, 2022 and July 31, 2021 were 26.0% and 25.9%, respectively. Our effective tax rate will generally differ from the U.S. Federal statutory rate of 21.0%, due to state taxes, permanent items, and discrete items relating to stock award deductions.
Twenty-Six Weeks Ended July 30, 2022 Compared to Twenty-Six Weeks Ended July 31, 2021
Net Sales. Net sales decreased by $28.3 million, or 4.1%, to $660.5 million during the 26 weeks ended July 30, 2022 compared to $688.8 million in the corresponding period of fiscal year 2021. Our net sales decreased primarily due to lower demand across most product categories as we anniversaried the increased demand during the first half of fiscal 2021 driven by the COVID-19 economic stimulus package (the American Rescue Plan) and social unrest and the impact of current year consumer inflationary pressures and recessionary concerns. These headwinds were partially offset by our opening of 12 new stores since July 31, 2021. Stores that have been open for less than 12 months and were, therefore, not included in our same store sales, contributed $45.1 million to net sales. Same store sales decreased by 10.4% for the