Bullet Performance; Low Velocity ELD-X, Terminal Ascent, or Accubonds?

[Huntin_GI]

Ok gun gurus.

Picked up a Sig Cross. Went to the range with a couple different types of ammo to see how much velocity I would lose with the shorter barrel.

Everything was confirmed

Barnes TTSX 168
2580
2583
2588

Federal 150 Partion
2630 up to 2692 which seemed to be a dramatic spread but half a box in and it kept happening.

Federal Sierra Matchking 168
2475
2487


The Matchkings 3 shot groups were a ragged hole at 100 but obviously I this isn't a hunting round.


SOOOO, when considering factory ammo and anticipated velocities, which round would you expect to perform the best. I have narrowed it down to Federal Terminal Ascent 175, Hornady Precision Hunter 178 ELD-X, and the Nosler Accubond 165.

Which and why? I assumed slower velocity performance and BC are my most important considerations.

This is a "Do All Western States" rifle as I live in Colorado and apply across the west. Please forgive my ignorance as I am but a simpleton. 500yd and in gun. Steel at further distances but I'm much less concerned with steel.

 

[jmo]

Of your options, my Cross definitely shot the Terminal Ascent the best. I think the velocities I was getting were between 2400 and 2450 fps. I took a caribou at 100 yards a couple years ago with that combination and it performed flawlessly.

Last year I took another caribou at 150 yards with an ELDX handload that had a muzzle velocity of 2350. Also worked perfectly. The bullet did not exit, however he died 15 yards from where he was shot.

I could never get accubonds to shoot in my rifle, in fact I had a hard time getting anything to shoot well from it. I was a little disappointed in it to be honest, but really love shooting it and the concept of it. I got a new barrel for it in 7mm-08 and now it seems like everything is sub moa without any effort. Have fun with your Cross! Even with the issues I had it's still my favorite rifles.

Sent from my SM-G973U using Tapatalk

 

[eoperator]

I mean this in the best way possible but if it was me I would trade that sig for a different rifle and caliber if you want a do it all rifle good for 500yrds. The 168 smk at 2480mv would be below 2000fps at 300yrds, 1600fps at 500yrds.

 

[Huntin_GI]

I mean this in the best way possible but if it was me I would trade that sig for a different rifle and caliber if you want a do it all rifle good for 500yrds. The 168 smk at 2480mv would be below 2000fps at 300yrds, 1600fps at 500yrds.

With the availability of ammo, I just can't bring myself to move away from the 308.

Here's the other thing. The way I understand "effective bullet performance" is the minimum recommend speed to achieve caliber 1.5x expansion. The 2000fps threshold which is seemingly applied across all calibers.

Insert the acclaimed 6.5PRC. It doesn't fall below the 2000fps until 700. At which point, it "will not expand beyond 1.5 times its original size. The kicker being its original frontal area is only .0547. SOO acceptable expansion leaves the 6.5prc with an exit diameter of 0.08205.

The 7.62/.308" enters the conversation with a .0745 frontal area. At 1.5x the original frontal that same round a full expansion (2000fps) is .11175. This means to achieve the same expansion as a fully expanded 6.5prc, the 7.62/.308 bullet only needs to "expand" by a margin of 1.1x.


Again, I am not trying to debate the caliber gurus as some of these guys have handloading down to a science. I'm just trying to find the load that will perform the best at those lower velocities that I know I will be dealing with.

 

[mt100gr.]

What offerings are available in .308 with a ELD-M bullet? It's a solid performer in game at lower velocities and the 6.5 147gr version shoots beautifully thru my Sig Cross. My load leaves at a mild 2540fps but I'd have zero reservations dropping one on a game animal at well over 500yds given the results I have seen with that bullet.

 

[RMM]

The matchking isnt a "hunting" round but neither is the tipped matchking and that bullet is straight up nasty on game. I would try some TMK's and see how they shoot

 

[HandgunHTR]

Is there a specific reason you are looking to go so heavy in a 308? If you want "500 and in" performance, I would be looking at 150-160 grain loads. A 150 grain Nosler Partition will kill anything the West has to offer. Another one that doesn't get much love on the Interwebs but performs very well on game is the 150 grain Hornady Interbond.

 

[hereinaz]

The matchking isnt a "hunting" round but neither is the tipped matchking and that bullet is straight up nasty on game. I would try some TMK's and see how they shoot

Yup. Match bullets make awesome hunting bullets. Just make sure the tip isn’t clogged. Berger hunting bullets are all I use. I have multiple one shot kills out to 1000 yards which was the last kill with my rifle.

I used Sierra match kings in my 308 for a buffalo hunt out of my 18” .308 because I was hunting out of a blind and had no shots over 150 yards. Killed her no problem.

As long as velocity on match bullets is over 1800 fps on impact it will expand. Plastic tips help expansion. And, you don’t want a closed or clogged tip on the open tip style. The ELDx are basically just match bullet that had a baby with a hunting bullet. They are just built to stay together in the back half and the front half to blow up.

 

[hereinaz]

With the availability of ammo, I just can't bring myself to move away from the 308.

Here's the other thing. The way I understand "effective bullet performance" is the minimum recommend speed to achieve caliber 1.5x expansion. The 2000fps threshold which is seemingly applied across all calibers.

Insert the acclaimed 6.5PRC. It doesn't fall below the 2000fps until 700. At which point, it "will not expand beyond 1.5 times its original size. The kicker being its original frontal area is only .0547. SOO acceptable expansion leaves the 6.5prc with an exit diameter of 0.08205.

The 7.62/.308" enters the conversation with a .0745 frontal area. At 1.5x the original frontal that same round a full expansion (2000fps) is .11175. This means to achieve the same expansion as a fully expanded 6.5prc, the 7.62/.308 bullet only needs to "expand" by a margin of 1.1x.


Again, I am not trying to debate the caliber gurus as some of these guys have handloading down to a science. I'm just trying to find the load that will perform the best at those lower velocities that I know I will be dealing with.

For match bullets, the factory number is 1800, but some guys who would go all the way to 1400.

Match bullets act differently than hunting bullets. The way you deploy them is different. It’s a different philosophy. They go in a few inches then just come apart. I shoot them into the lungs just behind the shoulder bones. It tears up both lungs. Animals drop right there or stand there wondering what just happened. I have only had two deer run but they were dead in 40 yards. I put three into a bull as he stood there, then he tipped over backwards down hill after taking three steps.

 

[Huntin_GI]

Is there a specific reason you are looking to go so heavy in a 308? If you want "500 and in" performance, I would be looking at 150-160 grain loads. A 150 grain Nosler Partition will kill anything the West has to offer. Another one that doesn't get much love on the Interwebs but performs very well on game is the 150 grain Hornady Interbond.

I have some of the 150 partitions but the gun didn't seem to like it as well as the heavier rounds.

 

[Huntin_GI]

For match bullets, the factory number is 1800, but some guys who would go all the way to 1400.

Match bullets act differently than hunting bullets. The way you deploy them is different. It’s a different philosophy. They go in a few inches then just come apart. I shoot them into the lungs just behind the shoulder bones. It tears up both lungs. Animals drop right there or stand there wondering what just happened. I have only had two deer run but they were dead in 40 yards. I put three into a bull as he stood there, then he tipped over backwards down hill after taking three steps.

This was exactly what I had been "thinking/concluding" but wanted those who have more experience to chime in.

If you were forced to choose between a "match" bullet and an ELDx or similar projectile, knowing you are going to be dealing with lower velocities, which way would you go?

 

[Seeknelk]

If it was me I'd definitely go 178 eldx. It proven to make nice wound channels at low velocities.
I've heard good things about killing with the 155 Lapua scenar also.

 

[doverpack12]

I listened to a podcast from Avery Adventures with Unknown munitions. No idea when it was recorded but I listened to it around Xmas. They had ELDM bullets expanding down to 1300 fps.

If anything eldx has a thinner jacket and would expand as well or better.

130 ELDM has done very well in my 260 but I start about 2900 fps

 

[hereinaz]

Run it through a ballistic calculator for your hunting conditions and see. Should be above velocity to kill inside 500.

I personally would look at a lighter bullet because velocity trumps weight/bc inside 500 for ballistics. You want the bullet to get there faster so less wind drift.

 

[2buffalo]

I have a small sample size with the federal TA out of my Cross. I went to South Texas this year on a hunt and shot two Javelina one at 300 yds one at 250 yds. Both expanded well and dropped them where they stood. One whitetail at 150 yds dropped where he stood. All bullets expanded well and exited. Can't help you out on elk size game.

 

[35WhelenAI]

With the availability of ammo, I just can't bring myself to move away from the 308.

Here's the other thing. The way I understand "effective bullet performance" is the minimum recommend speed to achieve caliber 1.5x expansion. The 2000fps threshold which is seemingly applied across all calibers.

Insert the acclaimed 6.5PRC. It doesn't fall below the 2000fps until 700. At which point, it "will not expand beyond 1.5 times its original size. The kicker being its original frontal area is only .0547. SOO acceptable expansion leaves the 6.5prc with an exit diameter of 0.08205.

The 7.62/.308" enters the conversation with a .0745 frontal area. At 1.5x the original frontal that same round a full expansion (2000fps) is .11175. This means to achieve the same expansion as a fully expanded 6.5prc, the 7.62/.308 bullet only needs to "expand" by a margin of 1.1x.

Given the 6.5 is a .257" or "quarter bore", expansion in the context of 1.5x bullet diameter is .257 x 1.5 = .3855". These calculations are using the formula for area, and calling it diameter. A .257" bullet expanded to 1.5x does not leave a hole measured in hundredths of an inch.

 

[Mule3006Elk]

I've harvested 3 mule deer with Federal Edge TLR (now TA). One 200 yards, one 180 yards, and one 225 yards. 2 dropped in their tracks. One ran 100 yards before dropping. The one that ran was a perfect meat saver shot so I would expect some run on that one.

 

[Wrench]

This was exactly what I had been "thinking/concluding" but wanted those who have more experience to chime in.

If you were forced to choose between a "match" bullet and an ELDx or similar projectile, knowing you are going to be dealing with lower velocities, which way would you go?

At your anticipated velocities, match 100%.

 

[Huntin_GI]

Given the 6.5 is a .257" or "quarter bore", expansion in the context of 1.5x bullet diameter is .257 x 1.5 = .3855". These calculations are using the formula for area, and calling it diameter. A .257" bullet expanded to 1.5x does not leave a hole measured in hundredths of an inch.

Yep. Lol. This is why I don't usually engage in public math. Now that we have sorted that out, let me dive right back into public math!

So .3855 is an acceptable killing hole, that would mean a .308 bullet would only need to expand by 1.25x to achieve the same kill hole? Yea?

Thus, acceptable velocities would include those capable of only expanding the projectile by 1.25x meaning sustainably slower velocities are now "acceptable."?

 

[35WhelenAI]

Yep. Lol. This is why I don't usually engage in public math. Now that we have sorted that out, let me dive right back into public math!

So .3855 is an acceptable killing hole, that would mean a .308 bullet would only need to expand by 1.25x to achieve the same kill hole? Yea?

Thus, acceptable velocities would include those capable of only expanding the projectile by 1.25x meaning sustainably slower velocities are now "acceptable."?

By the math, absolutely correct. In reality, I don't know at what point once velocity has fallen off the bullet could/would potentially lose stability inside of the animal. You could end up with an equivalent diameter but terminal performance could be compromised. Weird things start to happen if bullets don't go straight when encountering resistance at the target.

As well, the minimum expansion threshold is for reliable expansion to whatever extent the manufacturer calls. Reliable expansion is one thing, then how much expansion occurred at the reliable expansion threshold. May not be what we envision when thinking the traditional 1.5x.

I'm sure there are times an individual bullet expands at lower velocity and there are probably times when it needed another couple hundred feet per second.

I add a couple hundred feet per second to a manufacturer's threshold then I feel I'm covered. I don't see the point or have a use to push it when a live animal is involved. YMMV.