Quick Drop vs Danger Space

[24valve]

A couple points.
First, you guys are making a lot of my example of a 8” plate at 600 yards, and I think youve misunderstood me. Yes, thats a smallish target at long range, but that wasnt the point. The point I apparently failed to make is that an 8” target isnt so far from the vital size of a wt deer, and yet multiple people in this thread talked about using quickdrop out to, and past, 800 yards. I am well aware how hard an 8” plate is to hit at 600 yards, I was simply pointing out that the qd error ALONE that folks are saying is acceptable (.2mil) is already enough to move the center of your cone completely off the edge of that target, and only then do you start adding the dispersion from all the other sources of error around that.

I don't believe anyone in this thread has said they've shot animals out to or past 800 using quick drop. Folks have mentioned that their guns align with QD that far, but that is not the same thing.

Yes, 0.2 mil is a significant offset at 600 yards and moves your POA to the bottom edge of an 8" plate, but the point was that first round hit rates are terrible on an 8" target in complex terrain to begin with.

I know we are discussing the boundaries of QD, but the 0.2 mil error is getting taken a bit too far in this discussion - the intent of it is to be used when fitting a QD curve to your data, not to stretch QD as far as possible.

The reality is that for even for the majority of hunters that shoot regularly, most situations will still have an ethical shot range shorter than max QD range (assuming QD friendly gun), so the max QD range isn't critical. If an ethical shot is far enough that you're concerned about an error, then just check your app to verify any difference - using QD doesn't exclude other methods, nor necessitate it's use in every situation.

But if you're looking for a hard line in the sand to delineate QD/range card use, then just cut it off whenever the calculated drop deviates from your base+/-correction at all and avoid any concern of the QD error at longer distances.

Second related point this^ brings up is maybe part question because I dont know this to be true for certain—but this is how it makes sense to me.
I dont think you can account for a .1 or .2 mil QD error by using the ranging error function. Im not certain, but I believe that function in the wez applies the ranging error on a bell curve, where only a small % of the shots will land at either extreme of error, and most will be concentrated nearer to the center, ie mostly correct range. That is notably different from QD error, where at any given range whatever error youve allowed is constant, always in the same direction and always the same amount. If Im correct in thinking about it this way that’s much more akin to your zero being off by .1 or .2 than it is to a dispersion error. If so, then a ranging error would simply add a small amount of vertical dispersion both up and down, but with 2/3 of your shots still showing very little error—hence why the wez isnt degrading your hit rate much. Wheras the .1 or .2 QD error will take that entire “cloud” of dispersed shots, and shift the entire cluster of impacts up or down by .1 or .2mils. I dont think the wez can simulate this, but if true then it would more significantly degrade hit rate compared to whats shown.

That is a good point about WEZ utilizing a bell curve rather than shifting the mean/shot cloud, but I do not know a better way to model this in WEZ for you.

 

[Kjc103]

Follow up on this.

My 20” 6.5cm which has more drop than basic qd formula allows, becomes pretty close to spot-on with a 140 yd zero. My sight height and DA are quite different than yours, but it still works, and it works across a wide range of DA.

My 270/lrx combo, no amount of fiddling with zero distance helps. On an extremely cold morning at sea level (ie DA of +\- -4000’) its ok, but as soon as I go up in DA to normal shooting/hunting it goes south fast. Zero distance does not seem to help this gun.

Regarding the give and take between qd and danger space (remember that?) it seems manipulating the zero distance is more of a trick for guns that are slower than is “qd ideal”, not so much for a flatter shooting gun. So this does not seem to be a trick that would allow having your QD cake, and eating it too (high danger space).

Adjusting the zero 40 yards or so may rattle the purists but I can assure you, it works exactly as it should.

 

[4th_point]

@4th_point that was also my point—QD error is an offset just like a zero offset, not a source of dispersion. The center of your cone will be off. Some portion of your cone will still be on, but for sure it puts more than half your previous hits, including a significant portion of the center of your cone where most shots land, into the miss-zone on that example target. Clearly still plenty close for a Hail Mary second shot on an already-wounded animal (esp if bigger target) when the alternative is a wild ass guess or not taking it at all, but imo questionable at best to rely on as primary for a first shot at a critter. Again, part of what Ive been trying to ask folks about, ie if they use qd as primary vs a “backup”, how far,etc due to this specific issue.

Mac,

I think you have a good handle on the situation, and you've identified the limitations of QD that some may not have considered.

And I believe that you have pointed out that the variables that negatively affect QD, will also affect a BDC reticle or BDC turret, but for some reason people embrace QD but disparage any form of BDC. Each may require a work around, depending on situation.

Suggestion:

Maybe start a new thread and specifically ask who uses QD as primary or backup? I bet you'll get more contributions.