Dr. John Stutz, UWF Ballistics Researcher

[HappyHellfire]

Hi, my name is John Stutz, PhD. I have studied external ballistics for about 20 years now. I conduct research on new bullet shapes and the math behind how bullets fly. I also teach courses in ballistics at the University of West Florida in Pensacola. I have recently started a small bullet company to try to market a new bullet design called Aerospike Bullets. I have some pretty extensive shooting experience with both pistol competitions and rifle hunting but I'm more of a researcher than an active shooter. Most of my shooting now is for prototype development and testing.

I love talking about ballistics and the little details of spin drift, jump, Coriolis, etc. Feel free to ask me those questions that have always bothered you about bullets.

 

[Baddog 0302]

What is the length of the 30 Cal. and the 6.5 ?

 

[HappyHellfire]

What is the length of the 30 Cal. and the 6.5 ?

6.5 1.229"
300 Blackout 1.314"
Win 308 1.238"

The 6.5mm is just short of the SAAMI standard for bullet length and some people have had problems getting tight groups.

The 300 Blackout fires great from a 300 Blackout 1:7 twist. I have had some people report decent results shooting it from a Win 308 but I don't recommend it. Maybe a 300 PRC?

The Win 308 is not as aggressive as the others with a less impressive aerospike "bump" but is rock solid out of a 1:10 Win 308.

Hope this helps!

 

[Rational Mind]

What is the BC Modifier of your bullet design ?

 

[HappyHellfire]

What is the BC Modifier of your bullet design ?

I don't report BC and I catch all sorts of hell over it.

The BC is a comparison of a bullet to a standard bullet like the G1 or G7. If the two bullets being compared are not similar then the method is just plain wrong. This is a common problem with people comparing long slender boattails to the G1. The number looks nice and big but it is misleading and wrong.

My bullets fly like normal bullets out of the barrel but as they slow down the aerospike "kicks in" and the drag is reduced. The drag curves don't look similar at all to a standard bullet, thus no BC.

This is one of the challenges I face. Most ballistic calculators won't accurately calculate my bullets out past a few hundred yards. I'm thinking of writing a custom drop table calculator for my website to fix this.

 

[Bodhisattva]

Have you ever testified in court? Asking because I always like to have an "expert" rolodex and I could add you. Even if not needed for testimony, but at least as a resource.

 

[HappyHellfire]

Have you ever testified in court? Asking because I always like to have an "expert" rolodex and I could add you. Even if not needed for testimony, but at least as a resource.

Never have. There are only about 10 PhD level external ballisticians in the country and we all know each other and have our secret handshakes. My understanding is that most "ballistics" experts have studied forensics. I never knew how they can claim expertise when there is no forensics program I am aware of that is mathematics intensive. External ballistics is primarily the field of aerospace engineering and is extremely math intensive.

 

[Bodhisattva]

Never have. There are only about 10 PhD level external ballisticians in the country and we all know each other and have our secret handshakes. My understanding is that most "ballistics" experts have studied forensics. I never knew how they can claim expertise when there is no forensics program I am aware of that is mathematics intensive. External ballistics is primarily the field of aerospace engineering and is extremely math intensive.

For your enjoyment, I present:

Devil in the grooves: The case against forensic firearms analysis

A landmark Chicago court ruling threatens a century of expert ballistics testimony

radleybalko.substack.com

 

[Snake-Eyes]

Hi, my name is John Stutz, PhD. I have studied external ballistics for about 20 years now. I conduct research on new bullet shapes and the math behind how bullets fly. I also teach courses in ballistics at the University of West Florida in Pensacola. I have recently started a small bullet company to try to market a new bullet design called Aerospike Bullets. I have some pretty extensive shooting experience with both pistol competitions and rifle hunting but I'm more of a researcher than an active shooter. Most of my shooting now is for prototype development and testing.

I love talking about ballistics and the little details of spin drift, jump, Coriolis, etc. Feel free to ask me those questions that have always bothered you about bullets.

Welcome to the Forum, doc. Thanks for sharing your time and offering your informed viewpoint.

For your enjoyment, I present:

Devil in the grooves: The case against forensic firearms analysis

A landmark Chicago court ruling threatens a century of expert ballistics testimony

radleybalko.substack.com

That is a really interesting article. Thanks for posting it.

 

[M60Gunner]

Always knew the “this bullet came from this gun” was a load of crap

 

[Bowhntr6pt]

Always knew the “this bullet came from this gun” was a load of crap

I read the article... tool marks, impressions, identification marks etc. are all just ONE factor to consider when seeking the truth. Considering the area where the courts is... not surprised.

Regardless of the opinion(s) in that article, tool marks, impressions, identification marks etc. can be reliable and accurate.

With that said, just like "eye-witness testimony", nothing is 100% per se on face value.

Sometimes these identification marks serve to point to an item and sometimes to exclude an item, it's not a one-way street.

As a former school-trained Crime Scene Technician I believe in the science and use of identification marks but also believe it's not 100%.

 

[Bodhisattva]

I read the article... tool marks, impressions, identification marks etc. are all just ONE factor to consider when seeking the truth. Considering the area where the courts is... not surprised.

Regardless of the opinion(s) in that article, tool marks, impressions, identification marks etc. can be reliable and accurate.

With that said, just like "eye-witness testimony", nothing is 100% per se on face value.

Sometimes these identification marks serve to point to an item and sometimes to exclude an item, it's not a one-way street.

As a former school-trained Crime Scene Technician I believe in the science and use of identification marks but also believe it's not 100%.

I’ve been fighting “junk science” as used in court to convict innocent citizens for years.
Juries love and want to believe experts. It’s good to do your homework and be prepared for the courtroom battle.

 

[HappyHellfire]

I’ve been fighting “junk science” as used in court to convict innocent citizens for years.
Juries love and want to believe experts. It’s good to do your homework and be prepared for the courtroom battle.

We usually divide ballistics into three fields: internal, external, and terminal. My area of study is external from the muzzle to the target. That being said, you can't study external ballistics without picking up a good bit of the other two. So, I'm not an expert on forensics but the idea that guns leave a "fingerprint" is a bit far fetched and I would need to see a pretty extensive study to support it. This is not black magic. Two guns with the same rifling shooting the same bullet with the same seating depth, powder charge, and barrel wear would probably leave very similar tool markings. Probably too similar to tell apart.

This is an offshoot to an interesting side topic. We tend to judge the surface finish on a bullet for quality but we also know that the bullet will be scarred up as it leaves the barrel. Our best estimate is that only 5% of the overall drag on a bullet is from surface friction. The traditional method of making bullets involves using dies that leave a smooth finish. With modern lathe machining, we can make any surface finish we want. What should be the ideal surface finish on a bullet?

 

[Bowhntr6pt]

I’ve been fighting “junk science” as used in court to convict innocent citizens for years.
Juries love and want to believe experts. It’s good to do your homework and be prepared for the courtroom battle.

No doubt ANY information used improperly is a bad thing and questionable information should be challenged. I would respectfully disagree that identification markings as addressed in the article is "junk science" per se.

Identification markings, like I said, are just ONE of MANY points of consideration that can possibly identify/include or omit/exclude a suspected item... to deny that on face value simply means you (not you personally) have an agenda. An agenda no better or worse than one who would insist the practice is full proof and absolute.

I'm sure there are as many people on one side of the fence as there are on the other concerning this topic... many, such as you, are much more learned than I.

With that said, I believe I can objectively apply a common sense approach when considering whether or not a specific identification mark includes or excludes. Always giving way to caution, uncertainty, and justice.

 

[Bodhisattva]

No doubt ANY information used improperly is a bad thing and questionable information should be challenged. I would respectfully disagree that identification markings as addressed in the article is "junk science" per se.

Identification markings, like I said, are just ONE of MANY points of consideration that can possibly identify/include or omit/exclude a suspected item... to deny that on face value simply means you (not you personally) have an agenda. An agenda no better or worse than one who would insist the practice is full proof and absolute.

I'm sure there are as many people on one side of the fence as there are on the other concerning this topic... many, such as you, are much more learned than I.

With that said, I believe I can objectively apply a common sense approach when considering whether or not a specific identification mark includes or excludes. Always giving way to caution, uncertainty, and justice.

You’d make a good juror, my Friend.

 

[JedClpIT]

No doubt ANY information used improperly is a bad thing and questionable information should be challenged. I would respectfully disagree that identification markings as addressed in the article is "junk science" per se.

Identification markings, like I said, are just ONE of MANY points of consideration that can possibly identify/include or omit/exclude a suspected item... to deny that on face value simply means you (not you personally) have an agenda. An agenda no better or worse than one who would insist the practice is full proof and absolute.

I'm sure there are as many people on one side of the fence as there are on the other concerning this topic... many, such as you, are much more learned than I.

With that said, I believe I can objectively apply a common sense approach when considering whether or not a specific identification mark includes or excludes. Always giving way to caution, uncertainty, and justice.

Oh my, how well this response applies to the persuasion of people on topics well beyond forensic ballistics. For we are all human and fallible, even scientist and the " more learned than I ".

 

[Recondo 101]

John, We're you around when the tests were run for the 9mm VS 45 ACP at Eglin with the shooting in the open range tests taking place at Hurlburt, which was then Field #9? Where the Eglin R&D folks had to redesign the 9mm 115 grain tea cup projectiles to get the 9mm through the minimum accuracy requirements of the test. The original 115 tea cup design would not pass minimum standards in the test. They created the truncated cone bullet design offered it to anyone that would make them the ammo for the test, had one taker, and they gave the TC design patent to Hornady in exchange for 3,000,000 laded 124 grain rounds to shoot in the 9mm test, speakng of redesign of bullets. Did you know that occurred?
This is a redesign of a revolver round I built on a DW Super Mag frame with a 445 cylinder furnished by Bob owner of DW. By the time I got the gun and dies built and the ammo loaded and tested DW had sold to CZ. The right had loaded round is a 200 grain Saeco 30 cal that shoots 1/10 inch at 50 meters. The most accurate round in that gun.

 

[cjackson31]

6.5 1.229"
300 Blackout 1.314"
Win 308 1.238"

The 6.5mm is just short of the SAAMI standard for bullet length and some people have had problems getting tight groups.

The 300 Blackout fires great from a 300 Blackout 1:7 twist. I have had some people report decent results shooting it from a Win 308 but I don't recommend it. Maybe a 300 PRC?

The Win 308 is not as aggressive as the others with a less impressive aerospike "bump" but is rock solid out of a 1:10 Win 308.

Hope this helps!

Do you have any hypothesis behind why some individuals have issues with grouping on the 6.5s? What projectile model was the simulation and testing run against?

 

[Norm]

Very interesting. Have you found that a cannelure affects accuracy in an appreciable way?

 

[HappyHellfire]

Very interesting. Have you found that a cannelure affects accuracy in an appreciable way?

I have several shooters testing for extreme accuracy now. I haven't seen any impact in my testing but my testing is to characterize the bullet aerodynamic performance and not for accuracy.