.257 100g X Bullet / 100 Hotcor / 117g I'lock vs Dry N'paper

[bobnob]

A friend gave me a couple dozen 100g X Bullets to try in the 250 AI. While accuracy is promising I thought I'd try them in a comparison test with a couple of other bullets I am running.

So I ran two each of the 100g Hotcor SP, the 100g X Bullet and the 117g BTSP Interlock. I ran one of each at a faster speed to simulate an impact about 30y from the muzzle, and the second of each a little slower to simulate around 130y away.

Here were the results:

100g Hotcor
Impact speed 2950fps (note that I will run the Hotcors a bit slower than monos because I find they work much better at impact speeds from 2900fps down)
Penetration 19cm
Retained wt 44g
Expanded diameter 0.567

100g Hotcor
Impact speed 2675
Penetration 20cm
Retained wt 50g
Expanded diameter 0.575

100g X Bullet
Impact speed 3050
Penetration 23cm
Retained wt 60g +27g petals
Expanded diameter 0.392

100g X Bullet
Impact speed 2850
Penetration 24cm
Retained wt 91g + 8g petal
Expanded diameter 0.426

117g Interlock
Impact speed 2825
Penetration 20cm
Retained wt 50g
Expanded diameter 0.624

117g Interlock
Impact speed 2575
Penetration 21cm
Retained wt 74.5g
Expanded diameter 0.913

Photo below; top left 100g Hotcor at faster speed, bottom left slower speed. Centre top 100g X Bullet (faster) centre bottom slower X Bullet. Top right 117g Interlock faster speed bottom right 117g Interlock slower impact speed.

As always I'm willing to offer some layman's conclusions....

All these bullets did pretty much as expected. The X Bullet penetrated the furthest and expanded the least. The petals broke off for the most part and even though the paper layers showed the smallest "wound channel" of the three bullets, the petals flying off still wreaked a solid hole through there.

The Hotcor and the heavier Interlocks performed similarly to one another. Pretty good weight retention really for dry newspaper which is a very harsh test medium.

I think if i was chasing very large boars or really big red deer, the X Bullet would win favour. For average pigs and deer however I doubt one would have a large advantage over the others. For lighter game the 100g Hotcor going a bit faster might just have the edge.

Hope you enjoyed this test. Interested in any thoughts...

- Bob

 

[DrMike]

It is interesting to note that the lower speed registers deeper penetration and greater frontal expansion in every instance. While the penetration does not differ greatly, it is consistent. A priori reasoning would lead me to postulate that the greater expansion would inhibit penetration, which is not what your tests show. This would lead me to speculate that either the increased impact velocity forces the initially expanded frontal portion to fold over on itself or to speculate that the longer period of pressure resulting from less velocity causes greater pressure waves from bullet movement. Interesting report. I'll have to think on this some more.

 

[bobnob]

Mike I think what is hard to capture, is what happens along the length of the wound channel.

At one point or another along that channel, the bullet may or may not expand to a larger diameter, then bits break off and reduce the frontal diameter. I'd suggest this might happen more than once during the brief instants that the bullet is passing through the media, whether it be newspaper or actual flesh.

The slower of the two Interlocks was really mangled into an oblong shape. A large one at that. I'd generally suggest that wouldn't be conducive to a deep wound. But possibly that warping of the projectile could have occurred in the last several centimetres of travel?


It certainly is fun to do these experiments and think the results through later anyway, as you allude.

 

[DrMike]

The slower of the two Interlocks was really mangled into an oblong shape. A large one at that. I'd generally suggest that wouldn't be conducive to a deep wound. But possibly that warping of the projectile could have occurred in the last several centimetres of travel?

I noted the severe warpage (it was impossible to miss). This is not uncommon with cup and core bullets, and even occasionally with the frontal portion of other bullets. However, the penetration would lead to the conclusion that you stated that the warpage occurred in the final portion of travel. There must be significant resistance on the bullet and/or heat generated at that point. There has to be some fascinating physics at play throughout, though I'm not certain how one could conduct studies.

 

[bobnob]

There must be significant resistance on the bullet and/or heat generated at that point. There has to be some fascinating physics at play throughout, though I'm not certain how one could conduct studies.

Well the super slo-mo video with ballistic gelatin would be one way, though that doesn't appear great at simulating hard stuff like bone being encountered.

It poses the question of the value of using certain test media. I generally use wet, really soggy newspaper but in this test I was conscious of stories of X Bullets going and going, so to prevent them exiting the rear of the test media I used dry newspapers.

I quite like using newspapers because it allows me to fire around six bullets into the exact same bundle so I can directly compare relative performance.

Anyway the below photo might promote further thought. This is a piece of cardboard wedged in among the newspapers about 8cm into the pile. The order of the holes is the same as the order above in the photo where the recovered bullets are depicted.

You can clearly see the narrower wound channel of the X Bullets in the centre. The Hotcor if anything is creating the largest hole and resultantly, eventually penetrated the least.

The slightly wonky pattern of the six shots was due to me firing them offhand from around 10 metres in a howling gale that was quite off putting!

I suspect if I'd used my normal wet newspaper, the X Bullets would have extended their penetration advantage, but using the dry newspaper I think compressed the results into smaller numbers.

 

[SJB358]

Interesting stuff Bob. I dig your tests buddy. Very good stuff. Those 100 grain Speers look pretty deadly to me buddy. Seems like they are just right in that little 250 Ackley.

 

[Seabee]

Some other things to point out here is it appears the cup core bullets shed a lot of weight and that lost weight is lead in the meat.
I hunted with Hornady interlocks and nosler spitzers for many years and recovered a number of bullets and found a lot of jacket separations and weight loss. Granted, these weren’t bonded core. For the last 15 years I’ve used Barnes tsx and TTSX and I find much less meat destruction and I’ve never recovered a Barnes bullet as they have always fully penetrated. They have also, judging from the exit hole, expanded every time and judging from the damage to hearts and lungs, performed flawlessly. I also hunted white tails with the e tip and gmx and had several cases where it seemed that they did not expand or minimally at best. The exit hole and entrance holes were the same. I did change from the tipped tsx to the regular tsx last year because I noticed the 257 tips were wobbling when rolled on a table. I went back to my 7mm tipped and the same thing. Got rid of them all and worked up new loads with the tsx. I use them in 24, 25, 7mm, 338, and 9.3 calibers with the same results. I’ve been testing different bullets on game since 74 and if I couldn’t use Barnes, I’d use nosler partitions. Just my .02

 

[PJGunner]

One of my most favored pet rifle and loads for deer hunting is my Ruger M77 in .308 Win. with the 156 gr. Speer Hot Core. Can't say much about recovered bullets and with one exception all passed clean though the deer. The one recovered was a head on shot as the deer faced me. The bullet passed through almost the full length of the deer and was found against a back leg bone which was broken. Muzzle velocity was about 2550 and the deer was lasered at 250 yards. The bullet was nicely mushroomed and retained 65% of its original weight. Most deer I shot with that load were shot at 150 yards or less and IIRC mostly less.
Paul B.