Do you go to the store or order online? I guess it wouldn't matter for me because either way it is the same store. Anyway, can you ask to double crush the grain?
I have a corona style mill. It was a present so I don't know how much it cost. But they can be had for less than $35. It would be well worth it to look into milling your own. If you get whole grains they will keep longer than pre-milled.
I agree with the previous - that is not a good crush and you will not get good efficiency from them.
With a lot of uncrushed kernals,I'm not sure a longer mash would help. but you could try. Also,make sure you sparge real well. That brings your gravity,& thus efficiency up.
Set up with a drill to drive the mill, I can crush around 7 lbs in two to three minutes, which includes the time to load up the grains. I do a fine crush for BIAB and could probably get more through for a coarser crush for a standard mash tun.
Needs to be crushed twice. You could take a rolling pin if you have a small amount-it will be tedious with a large amount and you would have to roll it in small increments. Otherwise go to your lhbs and run it through again, or invest in a good mill if you plan on doing all grain. That weak crush is wasting you money and gravity. Corona mills are cheap and work great but ideally the barley crushers are better and pricier,but a great investment. For me my batches are around 2.5 gallons so crushing 6 pounds in a corona mill is not too bad to hand crank and is a good work out, I also still get really good effeciency most of the time with my crush. Like others have said you can set up to run a drill also it if thats a problem.