Polymer tipped bullets

I have often wondered about the polymer tipped bullets from various manufactures. I have read of people seeing wisps of lead on paper targets that apparently came from lead tipped bullets that melted in flight. If the heat at the tip of a bullet can melt lead then the type of plastic used for bullet tips needs some serious consideration. But, I figured the bullet manufacturers knew a lot more about this than I did and had it all under control.

It turns out this was not the case:

the Hornady engineers observed a convex hump form when charting the new bullet’s drag. The hump was relatively small and usually occurred within the first 100 to 200 yards of flight, and following the hump the drag curve returned to its expected concave climb and drop. The irregularity may have been small and short-lived, but the shift from concave to convex, and back again, seen on the Cd vs. Mach Number graphs could only have one explanation: The bullet itself was changing shape in flight.

It did not take long for the Hornady team to realize it was not the whole bullet changing shape, only the non-metal component—the polymer tip.

The solution, of course, was to find a new polymer:

New polymers were tried and tested, and one was found that met the company’s criteria. With the new material, the Heat Shield Tip was born. Molded as precisely and consistently as previous polymer tips, the Heat Shield Tip boasts glass transition and melting points hundreds of degrees greater than the previous generation’s—475° F and more than 700° F, respectively.

This resulted in higher ballistic coefficients (BCs) which translates into less windage and drop.

My favorite bullet for .30 caliber long range shooting has been the Berger 210 grain VLD bullet. It has a G1 BC of .621. The Hornady 30 Cal .308 208 gr ELD™ Match bullet has a BC of 0.670. From 700 yards away with a .300 Win Mag with Boomershoot conditions this increases the velocity by 60 fps and decreases the drop by 2.6 inches. This isn’t enough of a difference to throw away my existing bullets but I think this is what I’m probably going to replace them with.


7 thoughts on “Polymer tipped bullets

  1. joe:

    i am all for quantifying things. great fun. but, i do not view “ballistic coefficient” as the end all and be all of bullet performance. even at extended range.

    personally, i tend to regard my sierra matchkings w/ continuing favor. the “tips” on a sierra do not melt, nor do they deform. and, 2.6″ at 700 yards is just about .1 mil, hardly anything to “compensate” for at such a range. one click.

    if you can aim that close, then the bullet’s “bc” is inconsequential. berger’s are good bullets. sierra’s are good bullets. hornady makes a good bullet, as do nosler and speer. and, for that matter, barnes isn’t too bad. i would not feel “compromised” in the slightest were i “reduced” to the state of using any of them.

    quite frankly, none of them hinder the ability of a practiced shot to make a 700 yard hit, nor do any of them make that shot any easier. if you have a bullet that performs for you, i see little sense in jumping around all over the place looking for the magical bullet: there is no such thing.

    john jay

  2. Or stay with Berger, and run the 215 Hybrid, with a G1 BC of .691…

  3. Plus, Hornadys numbers have tended to be a bit “optimistic” when they are tested by independent users.

    I like Hornady’s and I use a TON of their AMAX Bullets for the 6.5 Grendel, but I think Bergers numbers are much more real than Hornadys.

  4. i’m a little surprised nobody ever considered the Tg value of the materials they were using. Its a fairly obvious issue all things considered. The term “hot lead” is not just a saying. Even approaching Tg of a polymer under the loads a bullet sees in flight is going to cause deformation.

  5. Just for fun I took the energy loss over time, over several hundred yards, for a fairly average 308 Win load, I believe it was, and came up with an average overall dissipation on the order of a thousand Watts. You all can do the simple math yourselves. Hmm. Didn’t think to look into the G force on the bullet due to atmo resistance in flight (not that it matters; its just interesting). It’s nothing like a spacecraft in re-entry, but it’s still a lot of dissipation for an Itty bitty bullet. The spin rates can get pretty astonishing too, which can be another possible cause of deformation in flight.

    I don’t care what anyone says; this stuff is fascinating. I’ve seen meplat trimmers for sale. They’ll reduce the BC slightly but make it more consistent from bullet to bullet. It seems Hornady is making them more consistent without sacrificing any BC. I say it’s a righteous endeavor, and you can see it in their faces and hear it in their voices that they’re stoked about it.

    And that poly tip isn’t only for consistency. It can also apparently be used to initiate expansion in hunting bullets, or as a safety “pad” in tubular magazines. That’s potentially three purposes in one.

  6. Huh. That’s probably why Hornady has completely gutted and rebuilt their 6.5 Creedmoor line.

    I need to shoot what I have and figure out what to replace it with.

  7. Hmmm… how might this apply to bullets from Leverevolution? I seriously doubt anyone considered Tg of the tip plastic as it’s pretty soft.
    Realistically, though, just as the rifle is more accurate than me, so are the bullets.

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