doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com MV vs. lead

MV is of course of little value in calculating leads, what counts is time of flight. Using an old chart from WW for lead #5's at 40yds a 1330fps mv load has a TOF of .1210 seconds, while one of 1135 fps mv has a TOF of .1365 secs. A bird traveling 50 mph = 73.333 fps would require a lead of 8.87 ft for the fast load & one of 10 ft for the slow one. Note this is a difference of 13.56 inches & is a "Fast" bird & must be traveling at 90° to shot line & this is extremes in shot velocities.
With 7½s the leds become 9.47ft & 10.6ft with the difference still 13.56 inches. This old chart did not include data for 1400 fps loads.

Sounds good , but in reality it does not work that way .
Next time you shoot some 40 yard crossers try a little "blind test". Have someone else load your gun for you , without letting you know beforhand if it is loaded with a "slow" or "fast" shell. You will not know the FPS of the shells you are shooting so you will have to lead all targets the same . Your score will remain the same . The only way you will know what shell you shot is from the amount of perceived felt recoil .

I'm an infrequent SC shooter, but I do a lot of low gun skeet. However, I've had very good SC shooters tell me they can tell the difference in lead when shells vary by as little as 100 fps. Maybe it's in their heads--entirely possible, since much of shotgun shooting is mental--but that's what they say.

I'm an infrequent SC shooter, but I do a lot of low gun skeet. However, I've had very good SC shooters tell me they can tell the difference in lead when shells vary by as little as 100 fps. Maybe it's in their heads--entirely possible, since much of shotgun shooting is mental--but that's what they say.

And a difference of over a foot at 40 yards can be pretty significant. If you're shooting REAL birds as opposed to clay targets and you're poking at a quail, if you're underleading just a bit and the center of your fast load's pattern is just behind, you'll still likely kill the bird because of the spread. Back that center off another foot +, with the slow load, and you'll probably miss. Same scenario with a pheasant, it can make the difference between a kill with the fast load and a crippling hit on the rear end with the slow one, if you use the same amount of lead.

I don't believe a difference of 100 fps at the muzzle will make a difference of 1' @ 40 yards. Whatever the difference actually is, if they are missing with the loads that start out 100 fps slower, they are barely hitting the clays with the faster loads. Smaller shot slows down so quickly, the time in flight difference is surprising little. At 40 yards, that 100 fps velocity difference has shrunk to about 20 fps, maybe less. Are those very good SC shooters knowingly using 100 fps slower shells and finding that their usual leads are not enough or are they missing and then deciding that THAT shell must have been 100 fps slower? I'd bet it's mostly in their heads, regardless. If they shoot the silly 1400 fps loads do they miss in front?

Not too hard to prove it is in their head. Run a entire box of new shells thru a chrongraph. You might be surprized to learn that the stated velocity is more or less a average , some will be faster and some will be slower .

I force myself to take the other side. Though I am a big believer in light loads for 27yd trap and stuff shot out to about a max of 40 yards. Especially, for repetitive shooting. But fast loads make a significant difference in hitting and especially killing things further out. Especially, at the extremes of range.
In the buddy/annie/miss & out/follow the leader etc. crowds you darn well better have a fast 1 1/8 oz. load to compete. A little more is better.
For killing birds, the answer includes using big shot. You can kill big wild pheasants nicely at great distance with 1 1/4 oz of #4 (#5 are ok). But you want some speed so there is shock power left. That is what kills things. Anwar Sadat never had one bullet hit him with a mortal wound. He died from shock. Shock kills almost all game birds. Especially, when they go down stone dead. At the extreme end of range, big shot that started off fast kills lots better.
Jake

I love it when people use calculators to "prove" that a lot of excellent sporting clay shooters don't know what the hell they're talking about when they say "speed kills."

I don't need a calculator to satisfy myself that "a lot of excellent sporting clays shooters don't know what the hell they're talking about". The fact is that a lot of excellent shooters in trap, skeet, sporting clays and in the hunting field DON'T know "what the hell they're talking about". Lots of excellent shots don't know 2 cents worth about ballistics or guns. No one proves this better than the current crop of suckers in the SC field who believe in and buy every gadget and useless gun and barrel modification that P. T. Barnum's grandsons come up with. I do an excellent job of having a BM every day but I know very little about plumbing.

Like I said, doesn't make much difference to me personally, because my loads don't vary more than 100 fps between the slowest target loads I shoot and the fastest hunting loads. However, I was using the figures Miller provided, which tell us that a difference of 200 fps in MV will result in a difference in lead of over a foot at 40 yards, on a crossing target. And if you take a look at a few pattern sheets, you'll discover quite quickly that a foot is a whole lot of difference--per the examples I gave above, on game birds when your lead changes by that much.

Clay targets aside, if you're used to shooting 1350 fps hunting loads and if you take some fairly long shots, it's probably not a good idea to all of a sudden start using 1150 fps loads--unless you're also going to increase your lead.

As for the famous example that loads with faster MV slow down quicker, and at long range the gap between a fast load and a slow load closes: nope, doesn't happen. The DIFFERENCE IN SPEED lessens, but the fast load continues to "run away" from the slow load. It's just that the fast load isn't gaining as much on the slow one at 40 yards as it is at 10 yards. But the slower load NEVER gains on the faster load. However, the fact that the difference in velocity lessens is important from an energy standpoint: there isn't going to be as much difference in shock at 40 yards between a fast vs a slow load as there is at 10 or 20 yards. If you want to increase retained energy, by far the best way to do that is by increasing pellet size, not increasing velocity. Therefore, the reason "speed kills" isn't due to retained energy, but rather to the fact that if you use the same amount of lead with a fast load vs a slower one, the faster load is much more likely to hit the front end of the bird rather than the back end.