Tom, in regard to the 'plunk test', keep in mind this test is valid only for the specific pistol you're loading for, and is a good way to ensure the round will chamber properly, but I'd recommend also having a chamber checker on the bench also, as these are chambered with actual .45 or 9mm chambering reamers and are viable for virtually all your pistols, not just the one that passed the plunk test.
On my bench you can see two chamber checkers, the black EGW has 8 'chambers' and is by far and away the most popular. The silver, single hole checker is from Lyman.
These are excellent gages to have on the bench for each caliber you're loading for, and will quickly become one of those tools you never knew you needed, but are glad you now have one.
And the 'flat nosed one' being referred to is what is considered to be the very best functioning, most accurate, and most popular SWC of all time, the H&G #68 (Hensley & Gibbs). I've been casting that bullet now for almost 50 years, have shot thousands of them through every 1911 I've owned and still do. In Bill Wilson's book, he refers to this bullet numerous times, as does all his co-authors.
It is said that if a 1911 will not function this bullet, the pistol needs to be corrected or sent down the road. It should function 100% in your gun, and if not, you should not just settle for a FMJ, but find out what the problem really is.
Here's Bill's book, considered to be THE reference for shooting, building a 1911 combat auto:
And a shot of Pg 184 that should be of interest:
And as Bill K. mentioned, a rough or unpolished feed ramp in the 1911 can be fixed up with the Dremel, the felt pad and some Flitz to make feeding like snot on glass on a hot day. Here's a peek at my Kimber Super Carry Ultra + 1911 .45 after a session in the shop. This one feeds virtually any bullet type or style with complete reliability and is one of my daily EDC's.
Here's a small sample of some of the bullet types I shoot in my 1911's. All function perfectly as they should, and having a properly tuned pistol is part of the equation too, the feed ramp being one of many aspects that may need attention to attain perfect feeding, but don't overlook your magazines, specifically the feed lips:
Hope some of this is of both help and interest, as it's no good having a pistol that only will function properly with one bullet type, when it should function perfectly with ALL bullet types to really be dependable.....and useful.
Oh, and before I forget, in regard to your water jug testing, you'll never find a 204R bullet after being shot into the jugs. The only thing you'll find is both core and jacket frags. I found this out years ago, but it's a good way to recover pistol bullets that are fired at much lower velocity. After years of watching both prairie dogs and ground squirrels get vaporized and chunk launched, sometimes finding a tiny jacket fragment, I have no hope of ever recovering a HV bullet shot into water. Maybe into a swimming pool, but don't expect much.
Those are all 9mm CD rounds that stopped in jug #5 from a 3" 9mm carry piece. HTH