Terminal ballistics at long range - Help

[Outdoorsman12b]

Looking for some help on long range killing power. We know that death is caused by shot placement and tissue damage. There seems to be a few schools of thought on here. The most common considerations I see are high BC, bullet construction, and velocity (usually 1800fps). I want to ensure good performance on game in the 5-800 yard mark and need to focus my efforts for the upcoming season.

Based on my two hunting rifles here is the scenario I am struggling with:

1) 6.5 CM with 147 ELDM - Maintains the 1800 fps until 800 yards and has .697 BC.

2) 7 RM with 160 Federal TBT - Maintains 1800 fps until 800 yards and has BC of .52 (168 Berger's are not that much different)

Between 5-800 yards there is not a whole lot of difference between the performance of the rounds on paper. So all things being equal am I just getting a .5mm bigger hole? (I should note that I don't reload so limited to the 160s in 7RM).

 

[Formidilosus]

1) 6.5 CM with 147 ELDM - Maintains the 1800 fps until 800 yards and has .697 BC.

2) 7 RM with 160 Federal TBT - Maintains 1800 fps until 800 yards and has BC of .52 (168 Berger's are not that much different)

Between 5-800 yards there is not a whole lot of difference between the performance of the rounds on paper. So all things being equal am I just getting a .5mm bigger hole?

No sir. The 147’s will create a wider wound channel at all ranges than the 160gr TBT. The 160gr TBT will penetrate deeper with a narrower wound channel than the ELD-M at all ranges.

The TBT is an excellent bonded, controlled expansion short to medium range bullet that blends deep penetration while trying to maximize tissue damage. It may be one of the best 0-500 yard bullets if massive fragmentation isn’t your thing. It is not an 800 yard bullet.

The 147gr ELD-M will penetrate deep enough even on close range shot on elk to be quickly lethal, but is much better past 500’ish yards than the TBT.

 

[BRTreedogs]

General rule of thumb is 1000 ft lbs for deer and 1400 for elk.
I'd look at the foot pounds not the velocity.
As long as the velocity is enough to open the bullet.

 

[Formidilosus]

General rule of thumb is 1000 ft lbs for deer and 1400 for elk.
I'd look at the foot pounds not the velocity.
As long as the velocity is enough to open the bullet.

There have been lots of threads discussing this, however Ft-lbs of energy is not a wounding mechanism and will tell you absolutely nothing about how much tissue damage a bullet will create, nor the depth or width of the wound. It is a useless metric.

 

[BRTreedogs]

There have been lots of threads discussing this, however Ft-lbs of energy is not a sounding mechanism and will tell you absolutely nothing about how much tissue damage a bullet will create, not the depth or width of the wound. It is a useless metric.

Ohh ok

 

[Formidilosus]

Ohh ok

What size wound does 1,400 ft-lbs of energy create? How deep of penetration and how wide will the wound be? Overall shape of the wound? What’s the difference with 1,300 ft-lbs using the same projectile?

 

[BRTreedogs]

What size wound does 1,400 ft-lbs of energy create? How deep of penetration and how wide will the wound be? Overall shape of the wound? What’s the difference with 1,300 ft-lbs using the same projectile?

I'm not interested in arguing with you.

 

[Outdoorsman12b]

The TBT is an excellent bonded, controlled expansion short to medium range bullet that blends deep penetration while trying to maximize tissue damage. It may be one of the best 0-500 yard bullets if massive fragmentation isn’t your thing. It is not an 800 yard bullet.

Ok this is good to know. If I do find a LR load for the 7 in the future I will make sure the bullet has the proper characteristics. Would it be accurate to say that an ELD-M in the 7 mag would just increase the expansion range and size of wound channel then?

 

[AZ_Hunter_2000]

What animals are you wanting to shoot out to 800 yards?

I ask since that really is pushing the limits on the 6.5 CM especially for larger/tougher animals.

 

[Formidilosus]

I'm not interested in arguing with you.

It’s not an argument. You stated-

General rule of thumb is 1000 ft lbs for deer and 1400 for elk.
I'd look at the foot pounds not the velocity.

I asked why, as that number does not give you a single point of information that helps you determine whether the projectile will create a lethal wound or not.

Would it be accurate to say that an ELD-M in the 7 mag would just increase the expansion range and size of wound channel then?

The low velocity expansion threshold is virtually identical between them. What a bigger bullet offers is either a deeper wound at the same width, a wider wound at the same depth, or a combination of the two- slightly wider and slightly deeper. A 180gr ELD-M impacting at the same velocity as the 147gr will have a wider and generally deeper wound. It’s not as big a difference as most would think however because the size of the wound channel is mostly about bullet construction, design, and impact velocity. There is far less actual difference in wound channels with like constructed bullets than most believe. That is, until you get to the fringes.

 

[Tmac]

I guess I’d ask what game are you going to hunt? Then I might add in the Federal Edge TLR or Terminal Accent in 7RM into considerstion, both are an attempt to take the basic TBT and keep the rear shank while softening the front for better opening at lower impact velocities. It is an attempt to deal with the limitations Formidilosus referred to. The basic design is one of the best hunting bullets ever designed for most applications imo. The tweaks for long range may just give one a bullet that can deal with a high velocity shoulder impact to slow impacts way out there with good expansion. May be worth a look.

As far as being concerned about velocity vs foot pounds, a couple thoughts. If only foot pounds killed, arrows wouldn’t. The three most important things are in order, placement, placement, placement. You place a bullet properly that is capable of cleanly killing an animal within its design parameters and you kill that animal. Any bullet can fail, but you get the idea I think.

Foot pounds is very dependent on velocity and to a degree using the numeric thresholds (1,000, 1,400 or ...) for game helps with cartridge selection at a given range. It basically, by its formula, helps move you towards bullets heavy enough and fast enough to potentially be lethal at a given range. Myself, I tend to ignore foot pounds. In a given caliber, I use a bullet of sufficient weight and construction, then make my max range the lesser of my ability or an impact velocity of +10% over the bullets minimum expansion velocity. I am concerned about terminal ballistics I guess. I also make sure and use my hunting areas environmental factors in the max range for me estimate.

So this is long winded, but if game larger than deer are on the menu and I was using a match bullet, it would likely be very heavy for caliber and in at least .30 caliber. For deer etc. smaller calibers should be fine. I use hunting bullets for hunting, not match bullets, so between your two options, it’s the 7RM for me, probably with a lesser max range. That said, I think there are better bullet options for both cartridges than the two you have to choose from.

 

[AZ_Hunter_2000]

I'd avoid the Federal TLR or it latest version. I had one rifle that loved it but then there was none to be found. Each time I spoke with Federal, it was always "next month" when their next production run will occur; it never did at least during the 8+ months I asked them about it. I finally gave up on that bullet specifically and Federal in general after that.

 

[Tmac]

I'd avoid the Federal TLR or it latest version. I had one rifle that loved it but then there was none to be found. Each time I spoke with Federal, it was always "next month" when their next production run will occur; it never did at least during the 8+ months I asked them about it. I finally gave up on that bullet specifically and Federal in general after that.

That sucks. I was considering trying the new Terminal Accent in one of my 270’s, but I see Midway is out, suspect it’s more of what you experienced.

 

[WCB]

That sucks. I was considering trying the new Terminal Accent in one of my 270’s, but I see Midway is out, suspect it’s more of what you experienced.

Can always buy them direct.

To the OP...I've killed a pile of animals with the Federal TBT out of my 7mag from 60 to 900yards. Have zero complaints. If I was hand loading and if the factory loaded TBT didn't shoot .5moa I would consider the new Terminal Ascent bullet.

 

[Sled]

That sucks. I was considering trying the new Terminal Accent in one of my 270’s, but I see Midway is out, suspect it’s more of what you experienced.

i learned last go round to stick to readily available projectiles and powder. now that i reload less, same goes for ammo. when materials aren't scarce you can play around with the new fancy stuff.

 

[Outdoorsman12b]

Can always buy them direct.

To the OP...I've killed a pile of animals with the Federal TBT out of my 7mag from 60 to 900yards. Have zero complaints. If I was hand loading and if the factory loaded TBT didn't shoot .5moa I would consider the new Terminal Ascent bullet.

Were you shooting factory or hand loading? If hand loading what MV were you getting?

 

[WCB]

Were you shooting factory or hand loading? If hand loading what MV were you getting?

Im shooting factory loaded