This Thread ended up being a bit long but I hope you will find it interesting. I have learned a lot about bullet expansion and had fun doing this series of testing. So let’s begin.

I have been involved in several discussions regarding the benefits of plastic ballistic tips and what degradation would occur if the tips were modified or removed from a bullet. I’ve always believed that the primary benefits of the ballistic tips are improved ballistic coefficient and “sales appeal”. When pulled from the bullet’s body, a ballistic tip is hiding a much larger hollow point/expansion cavity from the wind which obviously does improve the bullet’s ballistic coefficient (BC) compared to the tip not being there. As an example, the 85gr E-Tip has a maximum expansion cavity of 0.130" (almost ½ the bullet’s diameter), the 110gr TTSX is 0.100", and the hollow point opening of 85gr TSX, which doesn’t have a ballistic tip, is less than 0.050".

After seeing how rapidly the monolithic copper bullets are opening up during terminal performance testing and on game I have shot, I have also thought that ballistic tips could be promoting bullet expansion on impact with the animal, forcing the bullet open quicker and to a larger diameter. As an example, I have observed Hornady’s 130gr GMX is fully expanded before it enters an elk’s chest cavity based on the entrance wound on the inside of the rib cage is as large as the exit side.

To test this assumption, I modified some monolithic copper bullets, specifically Nosler’s 85gr E-Tip, Barnes’110gr TTSX, and Hornady’s 130gr GMX. Two modifications were done to the 85gr E-Tips. One with the tip shorten and filed blunt/flat but still protruding some length beyond the bullet’s copper body, and the other with the tip completely removed leaving the gaping expansion cavity. The 110gr TTSX and 130gr GMXhad just their tips removed leaving the large hollow-point exposed. The tips were easy enough to remove on the E-Tips and TTSXs (not so on the Hornady GMXs or any lead-core bullets I have). I place a loaded shell into my single stage loader without a die in it, raised the shell so the tip was just exposed above the top of the press, and then held the tip with a pair of wire cutters as the case was lowered. The tips just popped out exposing the larger than normal expansion cavities. I did have to recheck seating depth and recrimp as some bullets moved. The tip on the GMX had to be drilled out.

The assumption going into this test is, with the ballistic tips removed or modified, expansion would be reduced. Below are the results of the modified bullets pulled from the bullet trap at 100 yards. The 85gr E-Tip and 110gr TTSX were shot from a 6.8mm SPC II. The 130gr GMX was shot from a .270 Win. Note that these are monolithic copper bullets and the results below may not apply to jacketed lead-core bullets.

These are results. The bullets were shot into the bullet trap I have developed.

www.huntingnut.com/ind...ullet+trap

Nosler 85gr E-Tip – Surprise! Both modifications resulted in more expansion, especial when you figure in the effect of reduce BC on velocity (all impact velocities without the pointed plastic tips are estimates). The bullet with the ballistic tip removed was largest and you can see how the expansion cavity is stretched more. I was also impressed with the reaction of the water jugs on impact. Both modified bullets stop in the phonebook before they reached 1000 pages.

Barnes 110gr TTSX – Though not as significant, the bullet with the tip removed did expand wider and had a more stretched expansion cavity. The bullet with the tip removed lost one of its pedals which was next to the bullet after it penetrated through the 1500 pages of phonebook and 5 magazines. The unmodified bullet with the ballistic tip still installed lost two of its pedals in the water column causing it to loose significant frontal area, penetrating through the phonebook and 10 magazines. These are both significant over-penetration situations, especially at 100 yards (penetrations through just less than 1000 pages of the phone book should give you an exit wound on a broadside lung shot on Southern sized deer). Though some six8 hunters use the 110gr TTSX, it really is designed for the .270 Win. When shot from the higher velocities of a .270 Win (3400+ fps mv), there is a dramatic difference in expansion as shown in the photo below (.270 Win on the left).

The testing done with the 110gr TTSX in the six8 demonstrate the negative effects of limited expansion, which are less energy transferred and over-penetration. The picture below shows the foam-core board and the increased energy transfer caused by larger expansion (test conducted at 100 yards). Note how much larger the facture/shock area is around the 115gr Fusion impact which expanded to 0.7 inches. Another comparison is to look at the 110gr TTSX impacts and the 95gr TTSX which has demonstrated excellent expansion (95gr TTSX is superimposed in the upper left). The 95gr TTSX produced a slightly larger fracture/shock area at 300 yards than the 110gr TTSX did at 100 yards. This demonstrates why Barnes made the 95gr TTSX for the six8. The link below shows the results when hunting hogs with the 110gr TTSX in a six8 which were not favorable.

68forums.com/forums/sh...ght=Barnes

Hornady 130gr GMX – the GMX with the tip removed did expand to be larger than the unmodified tipped bullet, 0.563” vs 0.525”, and also expanded so much that it bottomed out the expansion cavity. However, during removal of the tip’s shank from the expansion cavity, the drill bit did cut into the internal copper wall slightly. I believe that is why the bullet’s expansion became lopsided. All GMXs I have tested previously and pulled from game have been symmetrical.

Based on this testing, there now is another reason you might want to remove ballistic tips other than wanting to use up some of your longer .270 bullets and have them feed through your AR magazine. From a terminal performance perspective in short range situations less than 100 yards, the advantage of removing the ballistic tips can be more expansion and reduced risk of over penetration. I do not recommend or see where it would be worth the effort to remove the tips on the 130gr GMX or 110gr TTSX. However, specific to Nosler’s 85gr E-Tip, with the tip removed it becomes a more effective home defense round (note, leave the seating die depth unchanged so the bullet seats the same giving plenty of magazine clearance). For those that need a lead-free bullet for hunting, the heavier longer 130gr E-Tip could potentially become an option in the six8 assuming it has the same effective expansion cavity design that the 85gr E-Tip has. I need to test the 130gr E-Tip to verify this but predict with the tip removed, it should stabilize in a 1:11 twist as the calculated stability factor improves to 1.26. The 130gr E-Tip would provide deeper penetration when hunting hogs with the six8 and possibly an advantage in areas of dense brush. Besides the advantage of being able to stabilize the longer 130gr copper bullet, there should be less chamber pressure and more powder capacity because the bullet can be seated longer in the six8 case which should also result in a higher muzzle velocity. Just remember to stay at least 0.050” off the lands to avoid pressure spikes.

Note: the bullets with the ballistic tips removed fed from the AR magazine ok but should be cycled through your specific action multiple times to ensure reliable feeding if you choose to do this. I do have my feed ramps modified so they continue down into the upper receiver (see example below) which could be benefiting reliable feeding with these modified bullets.

Here is another comparison of like bullets with and without ballistic tips shot from a .270 Win. Both these bullets are unmodified. One is a Barnes 130gr TSX hollow-point that is produced without ballistic tips. The other is a new Barnes .277 129gr LRX with a ballistic tip that is advertised to have a lower opening velocity, down from 2100 to 1600 fps. The LRX has the “new” cavity design that is claimed to be similar to the six8s 95gr TTSX (you will see later that they are not quite the same). These tests were conducted at 100, 300, and 500 yards. The LRX showed excellent accuracy at all ranges shot from my Tikka T3 Lite, < 1 moa. I expected the LRX to out expand the legacy TSX and I was not disappointed as you can see from the picture below. The 130gr TSX does well, especially considering the smaller expansion cavity, but the 129gr LRX does better and provided the largest recorded expansion at all 3 ranges of any monolithic .277 bullet I have tested, an impressive 0.611" at 100 yards and still doubling in size at 200 yards.

So if pulling the ballistic tips on monolithic bullets improved expansion, what would happen if ballistic tips were added to bullets that were originally designed not to have ballistic tips? To find out, I tested an 85gr TSX shot from a six8 and a 130gr TSX shot from a .270 with bullets modified to accept ballistic tips. Bullet expansion was worse with the tips installed and nowhere near the performance of the unmodified bullet. However, this really was not a valid test and more a schooling in how important expansion cavity design is. All bullet expansion stopped where the drill-bit stopped making the cavity to accept the ballistic tip. You can even see the original Barnes expansion x-cavity which continued deeper into the bullet. All these modified bullets with tips added over-penetrated, especially the 130gr TSX + tip which didn’t expand much at all and was too long to remain stable after impact. It yawed and finished its deep, over-penetration tail-first (just like the Berger .277 VLDs). The real take-away here is how good a job Barnes did in their TSX expansion cavity design which achieves so much expansion from such a small cavity.

To complete the search for knowledge and understanding, below are cross-sections of several 6.8/.277 monolithic bullets. You can see the expansion cavity in the E-tips and GMX are the largest. All the other bullets are pure copper where as these two are 95% copper/5% zinc – the same alloy used in copper jackets for lead-core bullets. An alloy of 95% copper/5% zinc is harder which is likely the reason the E-Tips and GMX need the larger expansion cavities. Here are a couple of interesting aspects to note. The 95gr TTSX, 110gr TTSX, and 129gr LRX all have different size blue ballistic tips and associated expansion cavities. The 95gr TTSX expands at lower velocity because it has the largest expansion cavity of the Barnes bullets. You can see there is less copper structure around the expansion cavity of the 129gr LRX when compared to all the other Barnes bullets. This is likely the reason the LRX is claimed to expand at lower velocity even with its smaller expansion cavity and why it is losing its pedals during expansion. Finally, notice how much smaller the expansion cavities are for the non-tipped TSX bullets yet their expansion is typically as good as or better than the tipped bullets within their designed speed/energy range.

Thus, from the results of this testing where every bullet with its ballistic tip removed expanded more, and the fact that monolithic bullets with ballistic tips require larger expansion cavities to achieve similar expansion to monolithic hunting bullets produced without ballistic tips; it can be concluded that the addition of the ballistic tip does not promote expansion for monolithic hunting bullets. Again, these results may not be applicable to jacketed lead-core rifle bullets that have ballistic tips.

Excellent research and testing Slim!!

Awesome write out Slim!
Great job.
Thanks!

great write up indeed .
so are you going to try to create a better hollow pointed copper solid with say a 3mm hole drilled 7- 10mm into it????

Slim, you have done a simply magnificent job here mate. Your analytical and testing skills are brilliant. I'm suitably whelmed.

Thanks for this mate, it certainly answers a few questions I have had bumping around inside my bonce for a while.

There's a lot of good info here slim thanks for sharing it..

Thanks guys. This was a fun project.

Elvis wrote:

so are you going to try to create a better hollow pointed copper solid with say a 3mm hole drilled 7- 10mm into it????

Elvis, that certainly would have the potential to work. However, that is a lot of work. I don't think you can beat Barnes and how they design their copper HPs plus all the copper ballistic tip bullets work consistently well.