Does nose shape matter at subsonnic velocities?
About 20 years ago I was shooting with one of my shooting Idols, Dave Gullo of Buffalo Arms in Sand Point Idaho. I had read about Dave Gullo, bought a lot of stuff on his online store site for BPCR supplies and equipment, I had run into him at a cannon shoot aoutside of Farragut Idaho and he and his shooting partner had invited me to his house to go shooting.
I had just gotten my Sharps Borschardt back from Doug Turnbull, had it with me and was excited to show Dave Gullo my prized rifle.
the Borschardt and some 457658 spitzers
At the range that day I pulled out my ammo, which was loaded with the Lyman 457658 which was a 485 grain spritzer. Gullo looked at the pointed 45/70 cartirdges, shrugged his shoulders and said, “you know those spritzers will not fly any better than SWC or round noses”
I was shocked, Gullo was like the BPCR god at the time, he would a year or two later win the Creedmoor worlds championship in South Africa that was restarted after close to a century of absence.
Gullo went on with his sacriledge, “Have you heard of Franklin Mann and his book Bullets Flight From Powder to Target?” I nodded that I had heard about it. Gullo then said, Mann proved that nose profile has no bearing on the flight of bullets that are subsonic.
I have never read that book, “Bullets Flight From Powder to Target”, cover to cover. I have found it online and browsed thru it looking for that information regarding nose profile affecting trajectory in sub sonic velocities, but browsing thru a book on line is not a good way to get every bit of information out of it.
Well I knew it made a big difference in super sonic bullets, but I had not heard of it in sub sonic, I eventually stopped using the 457658 bullet, because it did not perform as well as other bullets I cast for, but I always wanted to see it on target to prove it to myself.
I have brought this subject up before, as when Mr Hollowpoint came out with his spitzers that were to be long distance bullets.
Handloads.com shows a large difference between SWC and spitzers trajectories, the spitzer with a 81.4 grain bullet weight drops a full 12 inches less than a 81.5 grain SWC with the same velocity and same 100 yard zero, the Handloads.com ballistic computer is also for super sonnic loads. When I bought the spitzer mold off EBAY I had checked the trajectory and really felt it would extend the range of my Haley, but Gullo’s words still echoed in my mind.
Well I tested it today to see for myself.
I shot the NOE SWC bullet at 81.4 grains against the 84 grain 257388 Ideal/Lyman bullet at 260 yards.
Same sight setting, same air pressure, close to the same velocity, the difference that 2.5 grains would make, same alloy and lube, one bullet was 2.5 grain heavier than the other.
And they shot groups in the same postiion at the target dots I was shooting at, the 84 spitzers did not fly flatter than the 81.5 SWC even though Handloads.com said they should shoot 12 inches higher.
I need to do more work on wind drift, the spitzers did drift farther than the SWC bullets.
So your turn, tell me I made a mistake, that Gullo was wrong that this just can’t be.
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Well that was the shortest flounce I’ve ever seen… 😆
I doubt you are wrong.
You are starting at lower velocities than you do with a PB, so the BC is much closer at your velocities than it would be with a PB.
Am I wrong? I know its not the in-depth answer your looking for.
As far as wind drift goes, if the spitzer is longer and has more surface area, its likely to be affected more by a sideways push of wind regardless of its theoretical BC.
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Rc….beleive me….the most important thing on a bullet is the length according the shape.
Bullets center of gravity must be between the drag point and base of nose.
Α very shape nose transfer the weight to the rear and need less twist to stabilize or else bullet’s yawing motion never stop and tends to increase until hit the target (example: http://www.nennstiel-ruprecht.de/bullfly/fig26.gif ).
In other words a spitzer 25mm(in length) bullet act like a 22mm flat nose bullet on the same barrel .
….so overall spitzers are very sensitive and need a particular dose of twist ratio(not faster or slower) instead FN which you can drive them a little faster in order to get a minimal yaw .
Just try to set Cendrics Talondor 257 features at miller formula with the 102 spitzer and you ll find that you get a very low stability factor(that means the bullet performs like a crap for this set up).
In reallity that bullet is very accurate because as i said, it act like a smaller bullet in size.