Bullet Performannce

Elkaddict

Well-Known Member
Shot a 200lb buck last night with a 270WSM using 140g accubonds started at a chronographed 3200fps. At 250 yds, I hit the both heavy shoulder bones. Surprisingly, the bullet did not exit and was found just under the skin. Accubonds are supposed to have partition like weight retention which is typically 66%. The retained weight was 59grain or 42%. Had similar issue with a 300lb mule deer two years ago at similar range. I’m thinking notwithstanding the bonded construction, these are too soft at these speeds (impact velocity was just about 2700fps). I’ve taken large bodied deer at 350yds and beyond with perfect performance (racquet ball sized exits wounds). Anyone else have like experience with accubonds? I’m starting to understand why some call them accubombs….. Thoughts? These shoot so well in my Tikka I’m a little hesitant to change to partitions.F58219C2-EE7F-4298-97D1-B4BBD1DF3471.jpeg
 
That doesn't look horrible to me for a shoulder hit at 250 yards with a 140 grain bullet. I understand your concern about the weight retention, but that looks like a very nice sized mushroom. I used to shoot a 264 Win Mag with 129 grain Hornady Interlocks. On one deer I had the copper jacket lodged under the skin on the opposite side of a shoulder with zero lead left in the jacket.

My son and I are now both shooting 300 Win Mags with 180 grain bullets, so we are going to get pass throughs and big holes on everything.
 
Native, I’ve got a 7mm STW (160s at 3350) or 300WBY (165s at 3400+) or a 340WBY (210s at 3250). I’ve gravitated to the 270WSM because it shoots flat/hits hard but even in the light weight Tikka, recoil is such that I can still see impact. I might have to try some partitions or 150s in it.
 
Yes, your 270 wsm might be the near perfect sized deer caliber for nearly all conditions. We are shooting 300 mags because of blood tracking in native grass fields. The bigger the hole the better for us.
 
Looks to me as if the bullet did its job. You recovered the deer and the bullet. I know two holes are preferable, but it’s hard to argue with success. That said, I shoot a .280 Rem, (old school I know), with a 140 grain Sierra Game King and a healthy load of R 19 behind it. I also have a .300 WSM and I can’t see that the deer know the difference. I have to say though, we don’t have 200 lb. bucks where I hunt and very seldom a shot beyond a couple hundred yards. For the last few years I’ve always shot my deer in the high shoulder, I don’t mind tracking, but at my age and condition, I don’t fancy dragging one a hundred yards out of the woods.

BTW, congrats on the buck but…..no pics, it didn’t happen !:D
 
100% energy transfer with a bullet that remains in the animal. It’s been a long time since I rifle hunted but when I did, 140 grain accubond hand loads were my favorite pills to use with my 270 WSM. The perfect bullet construction for deer IMO. I always had two holes but the WSM packs a little more punch.


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These are the last two bucks with no exits. I understand the muley a little more because it was huge bodied. For perspective on the body size, those antlers were 31” wide. On the whitetail, you can see the bump where the bullet was found. I’ve included the Live Photo of the whitetail to give perspective to its body size.1A56CE13-17E7-4689-BB69-10948302F206.jpeg135596DD-9A76-4291-88B1-14FD96669954.jpeg 00D4BCF9-3EFC-43E4-9A1B-6F1021A1CF68.jpeg512490FD-C868-4827-95C6-443659DBB928.jpeg
 
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If you want high weight retention, switch to copper instead of a different lead bullet.
 
Shot a 200lb buck last night with a 270WSM using 140g accubonds started at a chronographed 3200fps. At 250 yds, I hit the both heavy shoulder bones. Surprisingly, the bullet did not exit and was found just under the skin. Accubonds are supposed to have partition like weight retention which is typically 66%. The retained weight was 59grain or 42%. Had similar issue with a 300lb mule deer two years ago at similar range. I’m thinking notwithstanding the bonded construction, these are too soft at these speeds (impact velocity was just about 2700fps). I’ve taken large bodied deer at 350yds and beyond with perfect performance (racquet ball sized exits wounds). Anyone else have like experience with accubonds? I’m starting to understand why some call them accubombs….. Thoughts? These shoot so well in my Tikka I’m a little hesitant to change to partitions.View attachment 24666
There is a flaw in your logic. Speed is not the major factor for penetration. Mass and speed are the components of penetration. For heavey bone hits as you describe you need more bullet weight. Just one old hunters opinion, as well as an understanding of the laws of physics. The deer were killed so the bullet did it’s job, but if you want complete penetration you need more mass.
 
There is a flaw in your logic. Speed is not the major factor for penetration. Mass and speed are the components of penetration. For heavey bone hits as you describe you need more bullet weight. Just one old hunters opinion, as well as an understanding of the laws of physics. The deer were killed so the bullet did it’s job, but if you want complete penetration you need more mass.
I think things are a bit more complex than that. I'm both a gun and bowhunter. With a bow, full penetration is the key to a blood trail for deer. Broadheads kill primarily by causing bleeding and lung puncture. Rifles are a bit different. The primary means of killing a deer is hydrostatic shock. When kinetic energy (mass * velocity squared) is transferred suddenly from the projectile to the animal, it creates a shock wave that goes through the body (which is mostly water). That shock wave disrupts and causes total systems shutdown. Most bullets are designed to mushroom. This intentionally limits penetration to ensure all of the retained energy is absorbed by the body. When a bullet fully penetrates the body and exits the other side, some of the energy is retained in the bullet.

How well a bullet penetrates depends on design of the bullet. When hunting larger game where heavy bone penetration may be needed, one can use bullets designed for more penetration. Penetration has many factors involved. Bullets can be jacketed for more penetration. Things like hollow areas behind ballistic points cause more mushrooming. It goes even beyond that. I think about some of the new turkey loads for shotguns (heavi-shot and TSS). Beyond ballistics and patterning, if a pellet hits a turkey neck bone at a long distance, will it penetrate and break the bone? Not only do we need to consider the retained kinetic energy of the pellet, we need to consider the hardness of the material. The hardness of some of the newer pellets transfers more energy than a similar sized soft pellet in lead. Lead deforms more at it hits applying the kinetic energy to a larger surface area. A hard pellet that does not deform as much on contact applies that same kinetic energy to a smaller surface area resulting in more penetration.

My point here is not to provide a specific answer, but just to say there is a lot of complexity involved. Most modern firearms we use for deer hunting will easily take a deer with a well places shot at a reasonable range. It is when we push the envelope, by selecting shots through heavy bone, taking long distance shots, or other similar things, that the specifics of the load come into play.

Much comes down to your situation. One may choose to use one load if they are taking shoulder shots so deer retrieval is easy with bang-flop shots. Another guy may choose a different load for broadside chest shots knowing that the deer will run and trailing will usually be necessary.

It is not as simple as a heaver bullet provides more penetration. While a heavier bullet will retain a higher percentage of the KE further down range, there is less KE to retain as a heavier bullet from the same power load has less velocity, and the velocity factor is more influential as it is squared in the equation.
 
I think things are a bit more complex than that. I'm both a gun and bowhunter. With a bow, full penetration is the key to a blood trail for deer. Broadheads kill primarily by causing bleeding and lung puncture. Rifles are a bit different. The primary means of killing a deer is hydrostatic shock. When kinetic energy (mass * velocity squared) is transferred suddenly from the projectile to the animal, it creates a shock wave that goes through the body (which is mostly water). That shock wave disrupts and causes total systems shutdown. Most bullets are designed to mushroom. This intentionally limits penetration to ensure all of the retained energy is absorbed by the body. When a bullet fully penetrates the body and exits the other side, some of the energy is retained in the bullet.

How well a bullet penetrates depends on design of the bullet. When hunting larger game where heavy bone penetration may be needed, one can use bullets designed for more penetration. Penetration has many factors involved. Bullets can be jacketed for more penetration. Things like hollow areas behind ballistic points cause more mushrooming. It goes even beyond that. I think about some of the new turkey loads for shotguns (heavi-shot and TSS). Beyond ballistics and patterning, if a pellet hits a turkey neck bone at a long distance, will it penetrate and break the bone? Not only do we need to consider the retained kinetic energy of the pellet, we need to consider the hardness of the material. The hardness of some of the newer pellets transfers more energy than a similar sized soft pellet in lead. Lead deforms more at it hits applying the kinetic energy to a larger surface area. A hard pellet that does not deform as much on contact applies that same kinetic energy to a smaller surface area resulting in more penetration.

My point here is not to provide a specific answer, but just to say there is a lot of complexity involved. Most modern firearms we use for deer hunting will easily take a deer with a well places shot at a reasonable range. It is when we push the envelope, by selecting shots through heavy bone, taking long distance shots, or other similar things, that the specifics of the load come into play.

Much comes down to your situation. One may choose to use one load if they are taking shoulder shots so deer retrieval is easy with bang-flop shots. Another guy may choose a different load for broadside chest shots knowing that the deer will run and trailing will usually be necessary.

It is not as simple as a heaver bullet provides more penetration. While a heavier bullet will retain a higher percentage of the KE further down range, there is less KE to retain as a heavier bullet from the same power load has less velocity, and the velocity factor is more influential as it is squared in the equation.
Clearly you are of the Jack O’Connor camp whereas I am more inclined toward to the Elmer Keith camp. Hydrostatic shock is a wonderfull theory but critters are killed by putting holes in their lungs and heart through blood loss or a CNS hit turning the lights off. Speed may be squared in the formula but I doubt any critter knows that formula. And it is that simple.
 
Clearly you are of the Jack O’Connor camp whereas I am more inclined toward to the Elmer Keith camp. Hydrostatic shock is a wonderfull theory but critters are killed by putting holes in their lungs and heart through blood loss or a CNS hit turning the lights off. Speed may be squared in the formula but I doubt any critter knows that formula. And it is that simple.
Notice I said "primary means". There is no doubt other factors contribute to an animals death. I'm not sure what an animal knows, but physics are physics. My point was that bullet design is an important factor in penetration, and a heavier bullet, all else being equal, does not generally provide better penetration in most cases because velocity is a higher order factor. Clearly, a heavier projectile, traveling at the same speed will provide more penetration.

None if this is simple. I think the OP poses a legitimate question of whether a specific bullet is meeting his needs. Heavier bullets pose other issues at long distances. I think he looking in the right direction by reconsidering bullet design if penetration is an issue for him.
 
I found that shooting very high velocities tended to only help me beyond 500 yards. Since a lot of my kill shots are under 500 yards, bullets sometimes did odd things when striking animals at speeds higher than optimum.

Dropped down to shooting a 6.5-06 many years ago. Excellent bullet performance from near to quite far with that using Berger VLD bullets. Now shooting 6.5-284, basically the same as the 06, and the 6.5x47 Lapua also with Bergers. Experiencing very consistent bullet performance out to max range which is past 500 yards.
 
I thought I’d supplement this post with a couple of different data points. As I noted in the thread “Colorado Success”, I shot a 5pt bull at 460yds with this same bullet. Two shots into the bull anchored the bull. Neither exited, and one was found quartering using the gutless method. It weighed 96 grains which equates to 69% weight retention. This was at an impact velocity of 2275fps. Overal, I thought this good performance given heavy bone was hit (between the two shots, the opposite shoulder was mangled).

I also shot a 185lb whitet at 215yds hitting just behind the onside shoulder and exiting the off shoulder after breaking bone. The buck ran 30 yds leaving an impressive blood trail.

After taking a number of animals, I have a better understanding of how this bullet performs when started at 3200fps. I presently have no intent to change.

This is the recovered bullet from the elk.
 

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I thought I’d supplement this post with a couple of different data points. As I noted in the thread “Colorado Success”, I shot a 5pt bull at 460yds with this same bullet. Two shots into the bull anchored the bull. Neither exited, and one was found quartering using the gutless method. It weighed 96 grains which equates to 69% weight retention. This was at an impact velocity of 2275fps. Overal, I thought this good performance given heavy bone was hit (between the two shots, the opposite shoulder was mangled).

I also shot a 185lb whitet at 215yds hitting just behind the onside shoulder and exiting the off shoulder after breaking bone. The buck ran 30 yds leaving an impressive blood trail.

After taking a number of animals, I have a better understanding of how this bullet performs when started at 3200fps. I presently have no intent to change.

This is the recovered bullet from the elk.
I would be very satisfied with those results.
 
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