I am becoming perplexed regarding shotshell velocity. Based on my calculations and experience I have always figured high velocity had little benefit. What’s a few inches, more or less, of forward allowance? And the ballistic coefficients of small lead spheres – 7.5, 8, 8.5, 9 shot sizes – are awful, so extra initial velocity differences are rapidly reduced to practical meaninglessness.
Now comes the rub. Some very knowledgeable types are focusing on 1350 – 1400 fps, 1 ounce loads using the best/hardest shot for long range sporting loads. I have read that Bob Brister was one top shot that urged B&P to make a truly long range sporting load (60 yds) and the result is a 1400 fps, 1 ounce load. Winchester’s AA “super” sporting load is likewise a very high velocity, 1 ounce load.
Numbers don’t lie. No matter how tight the pattern of a custom choked gun a 1.125 ounce load will put more pellets on target than a 1.0 ounce load. Choke increments are 5%. So, a 1.125 ounce load is ALWAYS 2 CHOKES “TIGHTER”, all other things being equal and considering the “bottom line”, pellet density.
What’s going on, Oh master of the gun? Is the remaining energy of a #7.5 pellet at 60 yards enough greater when launched at 1400 fps rather than the typical “super handicap” velocity of 1275 – 1290 fps to make a difference? I don’t have any hard data on the ballistic coefficients of small lead spheres and the problem in made worse by the trans-sonic regime of shotshell exterior ballistics. The BC used for accurate computations is probably variable, or a step function at least.
El Lago, Texas
You and I think along the same lines. I think that more slow lead beats less fast lead every time. A quick look at Lyman’s 4th edition tables shows that there isn’t much energy difference at 60 yards. Lyman’s doesn’t go up to 1400 fps, so I’ll use 1135 and 1330, still a 200 fps difference. Using #7-1/2s the tables show a pellet starting at 1135 fps retains .8 ft/lb at 60 yards compared to a #7-1/2 starting at 1330 fps retaining .9 ft/lb. Since things are rounded off to one decimal, the pellet started at 1200 fps also shows .9 ft/lb retained at 60.
Lowry’s program uses a different muzzle speed. Lowry uses the more customary 3 feet as his measuring distance. Lyman uses 3 yards. The difference for a #7-1/2 pellet is about 100 fps and .0072 ft/lb energy. Lowry comes up with a 60 yard 1135 fps #7-1/2 as retaining .59 ft/lb, while one starting at 1330 has .69 ft/lb retained. Using either Lowry or Lyman, the difference isn’t all that great.
Most ballisticians feel that a 1.0 ft/lb (and multiple hits at that) are what it takes to break a bird with any kind of reliability. Usually it’s a minimum of two hits, hopefully three. Clearly, the 1-1/8 oz load has a 10% greater chance of multiple hits because it has about 10% more pellets. People who feel that the hot one ounce load automagically shoots tighter than the 1-1/8 oz load simply haven’t done their patterning homework. High velocity increases shot setback just as much as extra payload does.
Obviously, the faster the muzzle velocity, the less lead. Lyman shows the 1135 fps #7-1/2 taking .246 seconds to go 60 yards, while the 1330 #7-1/2 will take .223. If the target is traveling 35 mph AND (big “and”) is going at a 90 degree angle (not always the case) the lead difference is 10.08″. At 60 yards, that is more than the effective pattern width, so it may matter to some people. It shouldn’t matter in the slightest if you simply add another foot of lead.
Then there is the recoil difference between a hot 1 oz and a 1-1/8 oz. In an 8 pound target gun, one ounce of shot at 1330 fps generates about 17.6 ft/lb recoil vs a 1-1/8 oz load at 1135 generating about 15.8 ft/lb. The 1-1/8 oz load has less recoil.
So, in exchange for the higher energy and ten inches less lead at 60 yards of the hot one ounce load you get 10% more recoil and about 10% less shot when compared to a standard 1-1/8 oz load.
Bottom line: both the hot one ounce and the standard 1-1/8 oz target loads have their advantages. It just depends on what you want. Me, I’ll take forza bruta every time. Too much is not enough! Victory through overwhelming power!
The Technoid writing for Shotgun Report, LLC
(Often in error. Never in doubt.)