Stevem
The answer is yes provided the resistance of your launcher is low enough.
Estes ignitors have a resistance of 0.8 ohms and require 2 amps to fire, so using Ohm's law we can calculate minimum all fire voltage of only V=ri=0.8x2=1.6 Volts! Voltage is never the problem, it the current draw.
Using Ohm's law, we can figure out the current that can be supplied by the launcher into an ignitor. It will depend on the internal resistance of the batteries, the resistance of the wires, and the switches, and the ignitors.
Below is a typical 7 AH Gell Cell data sheet that you can purchase for $18-$25 at a good electronics supply store or from a number of on-lines sources.
https://www.panasonic.com/industrial..._LC-R127R2P.pdf
The internal resistance of the battery is listed as 0.040 ohms, so it can theoretically deliver I=V/R=12/0.040=300 amps on a dead short (for a short time anyway).
With the potential of delivering 300 amps, (3.6 KW) it's not a toy, so you won't find one in your local department store. So to fire 10 Estes ignitors you need at least 20 amps. Note that the gell cell actually has a curve at 23 amp current drain, and it will actually deliver that current for 8 minutes, however to get this current out, you need a low total load resistance.
The total circuit resistance that will draw 20 amps is R=V/I=12/20=0.8 ohms. The total resistance is the resistance of the battery, the resistance of the ignitors, and the resistance of the launcher.
The Resistance of 10 Estes ignitors in parallel is 0.08 ohms.
To calulate the maximum launcher resistance you can tolerate and still deliver 20 amps you need to solve the equation 20=i=V/r=12/(0.04+0.08+R(launcher))
0.040+0.080+R=12/20 and R = 0.6-0.12=0.48 ohms
It would better to have a launcher resistance that is half of this value or 0.25 ohms.
Read
https://www.esteseducator.com/Pdf_files/1924_launch.pdf and you'll learn how to answer these questions.
You might want to go to the Estes Educator site,
https://www.esteseducator.com/cfusion/publications.cfm to get some further info.
Bob Krech