What's the length of an A1 Stock screw?

I browsed the last 40 pages of threads in the retro section and found this info:
A) it is half the length of the A2 screw.
B) cut off 5/8" off an A2 screw to get it to A1 length.

Therefore, assuming both A & B are correct, that would mean an A1 screw is 5/8" long and an A2 screw is 1-1/4" long.

Anyone have an A1 and/or A2 screw handy they can measure?

I'm looking to just grab a 1/4-28 x ??? flat head screw from work or a hardware store rather than buying one + shipping from a gun part supplier.  I haven't come across anything that would indicate this screw is anything other than a standard off-the-shelf fastener.

If you check the "Pay it Forward" thread, someone has an A1 stock screw on there.

Just cut it in half.