Do you believe Hornady

[Berger.Fan222]

What will Sierra and Nosler do or did they get their bullets right the first time?

Everyone has known for a long time that Nosler ballistic tips don't have anywhere near the advertised ballistic coefficients. This may be one contributing factor. Nosler publishes BCs as advertising; they have little interest in accuracy.

Sierra, in contrast, has led the industry in BC accuracy for a long time. Whether the TMKs have this issue is an open question. If TMKs were immune from melting, it seems that Sierra would have published this information my now. My guess is that they are looking into it more carefully.

To me, it may be a hint that the TMK has an advertised BC that decreases much faster with velocity (distance?) than the SMK (see figure attached). The melting and flattening of the tip in flight would explain why the TMK's BC decreases faster with distance than the SMK's BC, because the SMK has no tip to melt.

 

[Twoboxer]

. . . Whether the TMKs have this issue is an open question. If TMKs were immune from melting, it seems that Sierra would have published this information my now. My guess is that they are looking into it more carefully.

To me, it may be a hint that the TMK has an advertised BC that decreases much faster with velocity (distance?) than the SMK (see figure attached). The melting and flattening of the tip in flight would explain why the TMK's BC decreases faster with distance than the SMK's BC, because the SMK has no tip to melt.

Dunno what bullet/data you're looking at, but Sierra's published G1 BCs for the 175gr TMK's are significantly higher than the 175gr SMK.

Also the G7 BCs, a better more consistent model for total flight characteristics, show the 175gr TMK improving to .267 from the SMK's .243 as measured via live firing by Brian Litz.

ETA: My understanding is Sierra's published data is backed up by more live fire measurements than most bullet manufacturers. Given that, if I were forced to guess I'd say Sierra is more likely to have seen and already dealt with real world issues like tip melting. Whereas Hornady is more likely to have recently found the issue with their tips as they improve their test capabilities.

 

[chkunz]

Folks on this thread keep saying that the Hornady tips melted. Some of the magazine writers have said that the tips melted. Hornady (in the Dave Emery technical white paper) never said that the tips melted. Emery said that they were exposed to aerodynamic stagnation temperatures high enough to cause deformation given enough time. Emery did not attempt to define how much time would be required in his paper. Hornady tips melting has now been repeated enough that is now accepted as fact. Maybe there has been analysis or testing by Hornady or others that show that the tips melted, does anyone have any reference to this?

 

[Berger.Fan222]

Dunno what bullet/data you're looking at, but Sierra's published G1 BCs for the 175gr TMK's are significantly higher than the 175gr SMK.

Right, but the TMK BCs decrease much more strongly with range than the SMK BCs which is exactly what one would expect if the tips were melting.

ETA: My understanding is Sierra's published data is backed up by more live fire measurements than most bullet manufacturers. Given that, if I were forced to guess I'd say Sierra is more likely to have seen and already dealt with real world issues like tip melting. Whereas Hornady is more likely to have recently found the issue with their tips as they improve their test capabilities.

Sierra has been careful for many years to provide BCs over a wide range of velocities. Until now, Hornady had been providing BCs near typical muzzle velocities measured over 100-200 yards.

 

[Berger.Fan222]

Folks on this thread keep saying that the Hornady tips melted. Some of the magazine writers have said that the tips melted. Hornady (in the Dave Emery technical white paper) never said that the tips melted. Emery said that they were exposed to aerodynamic stagnation temperatures high enough to cause deformation given enough time. Emery did not attempt to define how much time would be required in his paper. Hornady tips melting has now been repeated enough that is now accepted as fact. Maybe there has been analysis or testing by Hornady or others that show that the tips melted, does anyone have any reference to this?

Right. Technically, the softening of plastic at elevated temperatures is not a real phase transition like ice melting to water or lead melting. It softens, so with an applied force it will flatten.

"Melting" is a more common term that lacks scientific accuracy but provides an accurate sense of what is happening in layman's terms.

 

[243winxb]

Hornady and Lee are the best at promoting. Not always for the best.

the gun is still in the process or firing while it’s trying to extract the cartridge case.

http://www.hornady.com/ammunition/superformance-in-gas-operated-firearms

 

[DaveTooley]

Folks on this thread keep saying that the Hornady tips melted. Some of the magazine writers have said that the tips melted. Hornady (in the Dave Emery technical white paper) never said that the tips melted. Emery said that they were exposed to aerodynamic stagnation temperatures high enough to cause deformation given enough time. Emery did not attempt to define how much time would be required in his paper. Hornady tips melting has now been repeated enough that is now accepted as fact. Maybe there has been analysis or testing by Hornady or others that show that the tips melted, does anyone have any reference to this?

You're correct in saying that melting is the wrong term. They soften and deform with certain bullets in a certain set of circumstances. Until Hornady changed their tip material every bullet manufacture used the same basic plastic to injection mold their tips. It's soft, it deforms easily and is easy to work with in the manufacturing of the tips. I've got both red and green tips here in the shop and there's not much difference between them. Rule #1 Don't do anything to make the phone ring. With that being said, before Hornady is done they will work their way through the whole A- Max's line. Just call it for what it is, product improvement.

 

[timeout]

Until now, Hornady had been providing BCs near typical muzzle velocities measured over 100-200 yards.

Just ran some Vmaxes from 100 to 600 yards yesterday and the actual drops came very close to the ballistics chart I ran using Hornady's published BC. Most were spot on, simply dial the MOA shown on the chart and Target impact was right on. One click (1/4 MOA) difference on only two distances. The way I shoot that could have been on me

 

[Berger.Fan222]

Just ran some Vmaxes from 100 to 600 yards yesterday and the actual drops came very close to the ballistics chart I ran using Hornady's published BC. Most were spot on, simply dial the MOA shown on the chart and Target impact was right on. One click (1/4 MOA) difference on only two distances. The way I shoot that could have been on me

Right. Most vmax designs won't experience much BC loss in under 600 yards because the speeds and time of flight aren't high enough. And even if there is a slight loss of BC in the first 600 yards, it is unlikely to show up in significant additional drop at those ranges.

Effects of tip softening and BC loss like need radar to see in the first 600 yards, because it will show up as velocity loss more than drop, since it happens late in the trajectory. The tips need time to warm, soften and flatten in flight.

 

[normmatzen]

Brian,
I answered the question, "Do you believe Hornady?"

And, I'm skeptical as I said. They can be holding back good evidence or they can be stretching the point. Either way, I am skeptical!

When my heavy gun gets back with it's new barrel, of course I will try
the ELD-M. Just as I will re-try the 180 Hybrid and the heavy SMK.
I have a hard time understanding why the ELD-M has a street price $5 or so higher than the same weight A-MAX. Even if the bullet shape has been improved, that doesn't make the bullet any more expensive to make other than tooling. And I can't believe the different plastic tip cost 2.5 cents more than the old one ( expecting the Hornady cost is bumped up 2 to 1 for the street price).
I just think that it is convenient that while "improving" the bullet from A-MAX to ELD-M a price increase of 20% was added, for essentially the same product with a different color tip!

 

[MGYSGT]

Pretty sure I read that Hornady used the other brands in their test (Serria and Nosler) and found the same thing happened to those bullets with poly tips.

 

[ChiefBlackwater]

I use their older amax ans have never experiance a problem even out of fast cartradges. Personally see it as falls. Have not way to proove it though.

A lot of Hornady products are way over marketed and do not work at all. Take a look at there concentricity guage. Indexes of the rim,? What a joke.

Spell check

 

[karrarararararar]

Spell check

It's an 8 year old thread....

 

[3Ackleys]

It's an 8 year old thread....

HaHaHa
Time machine check!

 

[c3d4b2]

From the attached it is feasible the bullets could become warm enough for the plastic tips to deform.

Temperature Measurement of a Bullet in Flight - PMC

This study answers a primary question concerning how the temperature changes during the flight of a bullet. To answer the question, the authors performed unique research to measure the initial temperatures of bullet surfaces and applied it to four ...

www.ncbi.nlm.nih.gov

 

[bozo699]

Spell check

Omg!……. The internet grammar police,…… policing a 8 year old thread!…..
Wayne

 

[Doom]

From the attached it is feasible the bullets could become warm enough for the plastic tips to deform.

Temperature Measurement of a Bullet in Flight - PMC

This study answers a primary question concerning how the temperature changes during the flight of a bullet. To answer the question, the authors performed unique research to measure the initial temperatures of bullet surfaces and applied it to four ...

www.ncbi.nlm.nih.gov

Just a clarification on this paper. It deals only with frictional heating due to drag. There is no consideration of the effect of the stagnation temperature that exits at tip of the meplat which is significant at supersonic velocities.

 

[c3d4b2]

Just a clarification on this paper. It deals only with frictional heating due to drag. There is no consideration of the effect of the stagnation temperature that exits at tip of the meplat which is significant at supersonic velocities.

This is a very good observstion.

 

[gunsandgunsmithing]

Fwiw, I've found intact plastic tips in a couple of deer after being shot. Not saying anything more or less than that.

 

[KMart]

Since this has reopened, I'll throw something in to the fray. One bullet that NEVER changed is the 30 cal 168 gr AMax plastic tip. They are STILL being made the old fashioned way. Wonder Why?

As an aside, if you have ever wondered what the plastic tip is, at least in Nosler, it is polycarbonate plastic. The same material that safety glass lenses and aircraft canopies are made from. They were one of our customers.