The impact of impacts

C

cdoc42

New member
Yesterday a military retired friend was using his mil-spec .308 rifle, Rem-700 action, with 172gr mil-spec ammo, and I was using my factory Browning X-bolt in 6.5 Creedmoor with handloaded 140gr Hornady ELD-X, graphed at 2695 fps. His was not graphed.

We were shooting at 18 x 18, painted white, steel plates from 300 to 1000 yards.

We noticed my rounds impacted the plates with a dark hit that was smaller than the hit at longer ranges, the size getting noticeably larger at 600 and beyond while his rounds impacted with a smaller size than mine no matter what distance it was hit.

Bullet construction obviously plays a role as well as the weight and velocity difference, but I wondered if the ELD-X greater expansion at the farther distance had something to do with the reduced velocity at that point, i.e., is there an "ideal" velocity that provides optimal expansion?

The question is interrupted by the understanding that the ELD-X is not designed to expand as does the ELD version, but my friend's bullet was a military grade -perhaps not designed to excessively expand at any distance-?
 
A bullet hitting steel is much different than a bullet hitting flesh. I don't think the size of the mark on the street can be compared to it's expansion. The eld-x IS an expanding hunting bullet

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There is eld-x and eld-m. There is no eld that i am aware of. The x is a hunting bullets with a thicker jacket to help prevent fragmentation. The m version has a thinner jacket and is a target bullet.

Gonna have to think about the marks on the steel.
 
So, your trying to compare splatter size on steel between a 30 cal using 172gr FMJ bullets compared to 6.5mm plastic tipped bullets?

Let us know when the "ah ha" moment arives...
 
What i understood the op to be saying was with both guns , the farther out the the steel was the impact marks got bigger.
 
I read it as that happening only with his gun, though that's not certain as he doesn't say whether the FMJ hits grew, too, but merely less than his did.

I expect the phenomenon will revolve around the impact depth in the steel. A close impact often creates an indentation or crater, so disintegrating fragments are directed partially back where they came from by the sides of the crater, while a distant disintegrating hit probably just flattens and spreads out without making a crater, so the disintegrated bullet fragments fly out more or less perpendicular to the impact, marking the surface more widely. For the FMJ, while I would expect it to come apart at close range, it may just compress into a button at long range and fall off the plate with the jacket still containing most of it; bent but not broken.

The first ten seconds of this video has examples of the crater's backward deflecting action. Then at about 8:20 in you see shots that are not cratering, but rather flattening and spreading out.
 
I'm sorry, let me offer clarification. I AM shooting "ELD Match," not ELD-X. My typo.

Shadow9mm correctly understood what I was saying, and Unclenick is correct as well.

Unclenick, I can't comment on the size of my friend's impacts other than to say they were consistently smaller than mine, but mine were obviously larger as distance proceeded. We started to discuss why this might be so, but neither of us is expert enough to debate the issue.

Two or three of our club members installed the 1000 yard range, so I have no idea about the strength of the steel target plates other than to say indentations or craters are only visible on the 300-yard plate. In fact, someone shot a hole through the plate, but all the other plates just have the paint knocked off, leaving a splatter mark. Close examination may reveal more than a splatter, and I will look at that next time I'm at the range.

Peripheral fragmentation certainly does occur, at least with my Creedmoor. In the past,I had balloons stapled to the wooden target board at 300 yards, and the steel plate is hanging from an extension at the right side, top of the board. One day, I hit the steel plate and two balloons to the left disappeared.
 
what I'm getting out of this is that your 140gr 6.5mm match bullets "splatter" more than mil-spec 172gr .30 cal bullets when they hit steel and the effect is more pronounced at longer range.

My guess would be that the 6.5mm bullets have a thinner jacket than the .30s, and might be moving faster at impact, and so more easily ruptured.

How does this not make sense to you?
 
44 AMP, it DOES make sense to me, but my question also involved why my impacts got larger at greater distances when velocity was slower. Note what I originally said:

"Bullet construction obviously plays a role as well as the weight and velocity difference, but I wondered if the ELD-X (should be Match, not X) greater expansion at the farther distance had something to do with the reduced velocity at that point, i.e., is there an "ideal" velocity that provides optimal expansion?
 
I don't know for sure why your bullet splash got bigger at longer range, my guess would be that its because you are shooting a "hard" target.

This is just a guess and based on something I saw happen many years ago, that seems to show a similarity.

Friend of mine liked to shoot .38 wadcutters are very low velocity. Like about 600fps velocity. I was watching one day when his target was an old refrigerator. Range was about a dozen yards or so...

On average, about 3-5 shots from each cylinder full would NOT penetrate the side of the old fridge. 1-2 shots would punch through. The bullets that didn't left a deep dent, and expanded to nearly an inch in diameter, and most would, literally fall straight down after impact. We picked up several right at the base of the fridge.

Now, these were soft lead bullets but the fridge "qualified" as a hard target at that low speed. SAME bullets moving a couple hundred FPS faster punched right through leaving small (.38cal) holes.

SO, what I'm thinking is, that when a bullet does not penetrate (particuarly a hard target like a steel plate) that a high percentage of the forward enegry is "reflected" back into the bullet itself and that may result in greater than expected expansion (up to shattering??) which would show a larger "splash" on your target plate than a bullet that is moving faster with more energy, or one that completely penetrates the target.

What I saw that day with those low speed wadcutters was that the bullets were, literally "stopped cold" and all of the energy left after what was used up making the dent went into expanding the bullet.

I think the same general principle is at work in your case. But, its just a guess...
 
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