a ground-state aluminum atom?quantum numbers:(n,l,m1,m2)a2, 0, 0, 1/2b2, 1, 0, 1/2c3, 0, 0, 1/2d3, 0, 1, 1/2e3, 1, 1, 1/2
Al has a 3p1 electronso thats n3, l1, m1 ?, m2 1/2You have only one |31x 1/2 state, so its e.
Glaser safety slug, or perhaps the completely useless CCI shotshells everything else has surprising penetrationI load all my own 9mm, from the ultra low cost practice to the high grade 'match' ammunitionthe ultra low cost is definitely as weak as 9mm will ever go, they don't even sell stuff this weak because in some guns it won't even cycle the action made for my Hi Point C9 9mm, and from the very first batch of practice ammo (now classified as light match ammo), I send a 90 grain LRN bullet downrange at 641 fps and it develops about 82 ft-lbless than a .22lr and just barely more than .25 acpyet it's observed penetrating 1/2 drywall, hollow doors and hard drives at 20 yards rangethe current loading is a bit faster, using a 100 grain LRN-FP bullet, same velocity, and just 90 ft-lbthe round's penetration is much higher, easily penetrates 3 sheets of drywall or two hard drive at 20 yards the variant for my Glock 19 has a 100 grain Rainier TCP RN and 690 fpsmakes about 106 ft-lbstill less than .22lr these loads are not to be under estimated, they can easily penetrate turkeys, chickens, multiple coconuts, and hog heads (right thru the skull)and they will still do that even fired thru several sheets of 1/2 drywall these loads are well below anything sold in storesnot even subsonic ammo is this weak so in your situation, Glaser safety or maybe you need to consider a shotgun and some 7.5 birdshotdo not use CCI shotshellsas i noted earlier, they're practically useless.
Getting below about 115 grains pretty much puts you into the arena of frangible ammo of one kind or anotherDRT has become really popular in that arena, Glaser is probably the most tried and trueI've not put a ton of thought into it, but to some degree, I might be inclined to go the opposite route - look for 147 grain or 158 grain subsonic ammo with a flat noseI know Fiocchi makes them, and in a controlled expansion round I know Federal makes them as wellThat might be your better pathThinkingblade
The lightest commercial load? Lightest I have seen is 115 grain for 9mm and the lightest commercial .40 SW load I have seen is the Corbon 135gr Honestly, neither of these rounds are going to spend the majority of their energy on the first thing they hitThis is why SWAT teams overwhelmingly carry a .45 .45 Auto 230 grain has the tendency to spend most of its energy in the first thing it hitsIt's big, heavy and slow-moving which also is why it has good knockdown power.
Besides frangible? none reallyactually, a .223 will penetrate less than almost any centerfire handgun round (obviously it will more than calibers like .25 and .32 acp)the general rule of thumb is more velocityless penetration, but that's not the case in all casesjust a general ruleso for 9mm, something reallly light, i think the lightest they go is 85 grains, but i can't remember the manufacturer.
