Something I never made real clear about DV is the lack of concern about calculating it at long range!
I worked those numbers out based on field performance at all ranges. In other words, calculate Displacement Velocity on muzzle velocity, go hunting and forget the numbers. Though DV will drop dramatically with the lower velocities of long range, game never seems to figgure out numbers anyhow, so they just fall down when hit. - That's a too simple answer, I know, but it has worked for the 16 years since I gave the formula to the public, and NOT ONE PERSON HAS EVER QUESTIONED IT'S EFFECTIVENESS NOR ARGUED THE ACCURACY OF THE FORMULA!!! You are in fact the first to ask about long range concerns!!
The biggest helper in extending long range Point Blank Range, as you are trying to do, is to use the highest scope mounts you can use with comfort, if using a scope. This allows you to look at a portion of the trajectory curve quite a bit farther out than if the sights are close to the barrel, and may add 25 yards or more to your desired goal of having the bullet hit within 3 inches to point of aim.
Here is a good time to discuss the DV formula a bit, as the above explaination doesn't make sense to the scientific minded.
The formula came to me while I was writing the third edition of Jacketed Performance with Cast Bullets. I'm not the type of mathmatical expert that would be able to figgure out such a number system, and in fact my calculating formula is far longer than necessary. Just multiply meplat diameter in thousandths of an inch times velocity and divide by 4. Do it in any order. In other words, when working with a specific bullet, divide the meplat diameter by four and put the answer in your little calculators memory, then multiply it times various velocities to get the DV you think you want. The main concern is not get a DV over about 130, if you expect to shoot game at close range, or game will run a considerable distence when hit at close range. If you'll be hunting from a stand and dead certain that no game will ever appear at ranges closer than, say, 100 yards, calculate DV with remaining velocity at that range, so your scientific mind can rest while you wait for your monster buck to appear.
Let me give you an extreme example of this crazyness. - I loaded a 240 gr 44 WFN to 1200 fps in a Marlin, with designs on my wife clipping grouse heads off with it. (The air fanned off this bullet at 1200 fps will kill or temporarily knocka close range grouse out if it passes close enough to the neck or head, even if it doesn't take feather off! So the 'target area' on a grouse neck is perhaps two inches wide! Same for quail. You might remember this when when you are hunting and a birds head looks too small for your ability.) She never shot it at a grouse, but after a year or two, I grabbed the gun up one day and went chasing Bambi. The first one hit at 100 yards dropped in its tracks. So did the second. Then a third at 30 yards, instant kill. Another at about 60 yards. This over several years, and I was a bit dumbfounded at how such a light load, calculated to work in close, should work at longer ranges just as well. The last deer, a large doe, was 100 paces from me, feeding in an open field, and I had to scratch the scientific itch, so I waited till she was perfectly broadside, then placed the bullet about 4 inches below the spine, and 4 behind the shoulder, so it could hit only lungs and not shock the spine. She dropped out of sight instantly, as I was belly crawling in the grass, so I jumped up to put another round into her when she attempted to get get up. I was CERTAIN she would run, but the only movement was a couple weak kicks of a hind leg. The wound was a full one inch in diameter clear through, but I'm sure, DV calculated with remaining velocities of this short pumkin ball bullet at that range would say otherwise.
I will now humbly submit, the formula had to come as an inspiration from God. I'm not smart enough to get such on my own. Never have before, or since, though he positively have given me at least as profound answers many times since, when I asked for it.
