CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.
I have done lots of experiments to try to blow up guns in incremental work ups.
If I just overload them, and they blow up, I don't learn much.
It is like an engineering professor told us about radial tension, "If the rocket blows up on the launch pad, you don't learn much."
Anyway, after thousands of such work ups, it is my opinion that if AA#5 won't blow it up, nothing will.
That is, it has the highest speed - density product.
That does not mean it will necessarily blow your gun up, unless you put too much in.
Where Power Pistol will just make a bigger and bigger fire ball when more powder is added, and so the effect of each increasing charge is small.
But AA#5 is peaky, and a small change makes a big spike in pressure.
Of all the pistol cartridges with small safety margins, an old Glock 40 S&W or an old Glock 10mm have got to be the ones closest to the edge.
So if you combine worn out old brass, an old Glock 40sw with terrible case support, some handloading technique variables, and AA#5, I can see a kaboom might happen.
On the other hand, with decent brass, and old Glock, and being careful with those AA#5 charge measurements, I can imagine a million rounds with no problems.
This is in contrast with Unique and 115 gr in 9mm, where a screw up bad enough to make real trouble just plain will not fit in the case.
What does it all mean?
If you use AA#5, don't screw up on the powder charge.
