According to the National Shooting Sports Foundation (NSSF) the latest Firearms and Ammunition Excise Tax Collection report released by the U.S. Department of the Treasury indicates that firearm and ammunition manufacturers reported tax liabilities posted significantly increases over Q2 2012.  

Reported tax liabilities of $224.3 million in the second calendar quarter of 2013 are up 40.3 percent over the same time period reported in 2012.

This 2013 second-quarter total surpasses the previous highest quarter reported (1st quarter 2013) by 12.6 percent and is the highest recorded since the U.S. Tax and Trade Bureau (TTB) took over record collection in 1991, surpassing the previous highest quarter reported (1st quarter 2013) by 12.6%.

The report, which covers the time period of April 1, 2013 through June 30, 2013, shows that $64.6 million was due in taxes for pistols and revolvers, $82.5 million for firearms (other)/ long guns and $77.2 million for ammunition (shells and cartridges).

Compared to the same time period in 2012, tax obligations were up 23.0 percent for pistols and revolvers, up 43.3 percent for firearms (other)/ long guns and up 55 percent for ammunition (shells and cartridges).
Translation to sales:

Using the latest tax liabilities reported as an indication of sales, a projection of $2.10 billion was generated for the second quarter calendar year of 2013.

Pistols and revolvers:
$64,605,922.45 / .10 = $646,059,224.50 = $646.06 million for pistols and revolvers

Firearms (other) /Long guns:
$82,489,884.18 / .11 = $749,908,038.00 = $749.91 million for firearms (other)/ long guns

Ammunition (shells & cartridges):
$77,154,456.94 / .11 = $701,404,154.00 = $701.40 million for Ammunition (shells & cartridges)

Total estimation of sales for the Q2 2013 quarter: $2,097,371,416.50.*

*The above estimates do not reflect retail mark-up and final retail sales.