New 155gr 6.5mm Berger on the horizon?

[fredo]

View attachment 1018936 View attachment 1018937 Here is for a 140 Hybrid and the second one is the 155gr.

There ya go!

Save ~2.5" of wind drift, and get two FEET more bullet drop for your trouble. What a deal!
If you use angular measurements, that would equal less than one "click" on a 0.1mrad turret @ 1K yds. (0.1mrad @ 1K = 3.6", for those not "experienced") So, in reality, the 'improvement' in wind correction of the 155 isn't even tangible enough to adjust my scope for...

As if that weren't enough data to opt against the 155, consider this:

A 140 JLK has a G1 of .630, much higher than the .607 G1 (.311 G7) of the 140 Hybrid you ran in your table above.
If you run your table above, noting that improvement, maybe you'll see the light? That improvement in BC just ate up 155's 2.5" (<0.1mrad) of wind gain, and then some! Run that same table above, and put a .630 G1 in, and see for yourself!

So, we're back to the "gamechanger" 155gr gettin' smoked by a 140 JLK. And that's "assuming" the G1 of .717 even holds, which is doubtful. Remember, that proof is from goin' by your own table & #s above, so don't be mad at me for pointing it out...(again)

I do appreciate seeing comparisons, though! It sure helps prove a point...

 

[dkhunt14]

There ya go!

Save ~2.5" of wind drift, and get two FEET more bullet drop for your trouble. What a deal!
If you use angular measurements, that would equal less than one "click" on a 0.1mrad turret @ 1K yds. (0.1mrad @ 1K = 3.6", for those not "experienced") So, in reality, the 'improvement' in wind correction of the 155 isn't even tangible enough to adjust my scope for...

As if that weren't enough data to opt against the 155, consider this:

A 140 JLK has a G1 of .630, much higher than the .607 G1 (.311 G7) of the 140 Hybrid you ran in your table above.
If you run your table above, noting that improvement, maybe you'll see the light? That improvement in BC just ate up 155's 2.5" (<0.1mrad) of wind gain, and then some! Run that same table above, and put a .630 G1 in, and see for yourself!

So, we're back to the "gamechanger" 155gr gettin' smoked by a 140 JLK. And that's "assuming" the G1 of .717 even holds, which is doubtful. Remember, that proof is from goin' by your own table & #s above, so don't be mad at me for pointing it out...(again)

I do appreciate seeing comparisons, though! It sure helps prove a point...

Target shooters don't worry about drop. That 3.6 inches of drift can be huge for a BR guy and probably just as important to an F Class guy seeing score is important. It definitely could be the difference between winning and losing. Hunters don't care as much because 3.6 inches at 1000 wouldn't cause a miss unless the target is small.
Matt

 

[fredo]

Target shooters don't worry about drop. That 3.6 inches of drift can be huge for a BR guy and probably just as important to an F Class guy seeing score is important. It definitely could be the difference between winning and losing. Hunters don't care as much because 3.6 inches at 1000 wouldn't cause a miss unless the target is small.
Matt

Yeah, but it was 2.5", and the 140 JLK just proved to negate that perceived advantage. So, what's your point...other than proving and reinforcing mine?

Also, can you even make a 1st round wind call in the field @ 1K to within 2.5" of center? Can ANYONE on the planet even do that???
If you can't, that just further dispells your position, which seems to flip/flop from "hunter" to "target" shooter, depending on which bias you're leaning toward...

 

[dkhunt14]

Yeah, but it was 2.5", and the 140 JLK just proved to negate that perceived advantage. So, what's your point...other than proving and reinforcing mine?

Also, can you even make a 1st round wind call in the field @ 1K to within 2.5" of center? Can ANYONE on the planet even do that???
If you can't, that just further dispells your position, which seems to flip/flop from "hunter" to "target" shooter, depending on which bias you're leaning toward...

I do both, but they are entirely different. Hunters want speed so range errors are less damaging. Target shooters don't care about speed near as much because they get sighters. Also because speed is almost always not as accurate. Unless you shot 1000 yard BR you would not see that. Over the years guys have shortened cartridges to get fuller cases of powder and more accuracy. The big boomers have disappeared in BR. The two games are just entirely different for desired results.

You keep referring to field and you cant compare the two. Different goals for end results. Matt

 

[fredo]

You keep referring to field and you cant compare the two. Different goals for end results. Matt

Ballistics are ballistics, regardless.

Show me how a 155 beats a 140 JLK...

 

[Shrek]

All the arguments about how the 155 isn't all that and a bag of chips I think miss its intended market. It's an eol hunting and field shooting bullet. It is meant for big cases pushing it at 3000fps+ not a 6.5x47 L. I hope my current 6.5 SAUM 8 twist is enough. If not then I'll build bigger. I see a Borden Ridgeline action in my future with a 6.5 WSM chambered barrel.

 

[Grimstod]

Yeah, but it was 2.5", and the 140 JLK just proved to negate that perceived advantage. So, what's your point...other than proving and reinforcing mine?

Also, can you even make a 1st round wind call in the field @ 1K to within 2.5" of center? Can ANYONE on the planet even do that???
If you can't, that just further dispells your position, which seems to flip/flop from "hunter" to "target" shooter, depending on which bias you're leaning toward...

The purpose of the word game changer is only related to IBS bench rest and F-Class shooting. Wind is the only thing that counts in these to disciplines. Not range or drop.
As for the JLK its getting enough of them that is the hard part. Seams though that no one really ever shoots though. I wonder why.

 

[284winner]

Opinions vary obviously. My opinion is that the 6.5-284 is the " On the line" cartridge for this 155. Any case larger, I see an advantage and any case smaller, not so much. That's my opinion and certainly it will not hold up to some others opinions. I will acquire a large handful in the future to test, that's a Gaurantee.

 

[Ledd Slinger]

Well time will tell. As I said with RL,17, maybe heavy for caliber in that short fat 284 case will help out using that powder. Had a member say it burns up barrels. All my barrels are expendable. They all go eventually. Same member said RL26 is the go to powder possibly for the heavier bullet. As I said, someone will publish some good load data once it arrives on the market.

Rl17 is an amazing powder that works across a broad spectrum of bullets and calibers that prefer all different levels of burn rates. But when you witness first hand just how fast RL17 will burn out a barrel, your thoughts on using that powder will most likely change. I learned my lesson the hard way.

Then add in the temperature sensitivity and it's just another reason why it does not make the top of my list for most hunting rifle choices.

 

[Grimstod]

In the process of making a wildcat with similar performance to the 6.5-284 myself. It will hopefully have same performance but with long barrel life and primer pocket life. When I was designing it I was wishing for a bullet like this one. Now it looks like there will be one. This is probably why I am a little more excited about it.

 

[284winner]

Rl17 is an amazing powder that works across a broad spectrum of bullets and calibers that prefer all different levels of burn rates. But when you witness first hand just how fast RL17 will burn out a barrel, your thoughts on using that powder will most likely change. I learned my lesson the hard way.

Then add in the temperature sensitivity and it's just another reason why it does not make the top of my list for most hunting rifle choices.

With the reloader 17, you don't need full case capacity to get good velocities. I'm hoping with 53 grains pushing the 162 Amax will give me decent barrel life. At around 2970-3000 fps, accuracy is good and cleans up well.

 

[Ledd Slinger]

For those of you that think you need a huge magnum to drive a heavy bullet. Mind you this is a 7x47Lapua.
And it drove 168gr bullets out of a 26in barrel at 2740fps.


http://bulletin.accurateshooter.com/2015/05/7mm-6-5x47-lapua-new-mid-sized-wildcat-cartridge-tested/


View attachment 1018996

Bullet speed efficiency is relative to bore diameter. This is where the term 'overbore' is derived from. As overbore cartridge's get bigger, they use more and more energy (powder charge weights) for less and less gains. You can only squeeze a bullet down a hole so fast.

Go to the opposite side of the spectrum with this 7x47 you mentioned and it is undersized for heavy bullets. Can't get enough powder behind them to push them at fast velocities.

When shooting 'heavy-for-caliber' bullets, the key is finding the sweet spot where case capacity to bore diameter ratio achieves maximum efficiency. Of course case design also comes into play there as well, but for 6.5mm, the most efficient cases with 140gr bullets hover around the capacity of +/- 60gr H2O. Those size cases will push those bullets very fast down a 6.5mm bore with smaller powder charge weights. Perhaps someone could chime in and tell me how much powder it takes for a 26 Nosler to push a 140gr bullet at 3200 fps? I'd be willing to bet it's about 15-20gr more than the 6.5 Rem Mag or 6.5 SAUM depending on burn rate of the powder.

As bores get bigger, larger case capacity is required to achieve max efficiency. As another example, 338 bore seems to be very efficient for pushing heavy bullets (250-300gr) with cases having 99-110gr H2O capacity.

In 30 cal, I believe cases like the 300 Win Mag, 30 Nosler, and 300 WBY sit right in the sweet spot for shooting heavy 215gr bullets. The 30 Nosler is probably the best choice of those 3 cases because it is the shortest of the three yet yields nearly identical capacity as the 300 WBY.

Are overbores faster? Yes. Are they the best choice? That's just comes down to personal preference. I like pushing bullets at respectably fast speeds with less powder to create less recoil and muzzle blast. Makes shooting for me more comfortable at the range, yet I'm moving the bullets fast enough for excellent long range trajectory and energy. I know this is also another big reason why the 6 Dasher is so popular in competition. It is a very efficient case in the 6mm bore. It gives good speeds with 105s and 103s, yet very low recoil and muzzle blast.

 

[Ledd Slinger]

With the reloader 17, you don't need full case capacity to get good velocities. I'm hoping with 53 grains pushing the 162 Amax will give me decent barrel life. At around 2970-3000 fps, accuracy is good and cleans up well.

True, but the other side of that is you may have a low case fill level depending on your seating depth. From my experience, low case fill can create oddball fliers, finnicky speeds, and create more difficulty with tuning. I like using powders that get right up to the base of my bullet. I don't want to be compressing the powder when I seat the bullet, but I want a good full case fill. Just seems I find more consistency there. I switched from 52gr of RL17 to 59gr of RL26 in my 6.5 Rem Mag and I am seeing much better consistency and forgiveness. Granted they are different powders so it's kind of apples to oranges, but the case fill is better with my load of RL26. I would over pressure the case if I were to attempt the same level of fill with RL17.

 

[284winner]

True, but the other side of that is you may have a low case fill level depending on your seating depth. From my experience, low case fill can create oddball fliers, finnicky speeds, and create more difficulty with tuning. I like using powders that get right up to the base of my bullet. I don't want to be compressing the powder when I seat the bullet, but I want a good full case fill. Just seems I find more consistency there. I switched from 52gr of RL17 to 59gr of RL26 in my 6.5 Rem Mag and I am seeing much better consistency and forgiveness. Granted they are different powders so it's kind of apples to oranges, but the case fill is better with my load of RL26. I would over pressure the case if I were to attempt the same level of fill with RL17.

How is your velocity by comparison( meaning 52 vs 59 grains) ? My capacity isn't low but not compressed either. I'm running my 284 in a short action gun. My COAL is 2.975. Accuracy is very good but again not sure how this will affect my barrel wear. I've heard RL26 is a good option but then so is H4350/4831.

 

[fredo]

Thanks for the charts.

I realize 5mph is a more realistic "let up", but don't we normally compare bullets in a 10mph? That would show closer to a 6" wind advantage.


Tom

I'd question the same thing, thanks for pointing that out. Not to mention the fact that he used of G7 curve (.311 BC) for the 140, and G1 (.717) for the 155. So, I just went with his comparison, and showed how the 140 JLK would beat it, given the parameters he laid out...

 

[fredo]

So, in the interest of accuracy & full disclosure, I just ran the #s on my app
Will use G1 BCs and my current ambients, 10mph L--->R, @ 1,000yds

155gr @ 2750 DROP: 8.0mils (287.3") DRIFT: 1.2mils (42.3")
140Hybrid @ 2950 DROP: 7.4mils (265.4") DRIFT: 1.3mils (47.0")

That's a 4.6" advantage, for almost two feet of drop dis-advantage

140JLK @ 2950 DROP: 7.2mils (260.2") DRIFT: 1.2mils (44.8")

That's SAME SAME SAME, at my ASL, right now
In a 10mph wind, for all intents & purposes, the 140JLK has SAME (mil based )CORRECTION for wind as the 155. If you run an 1/4MOA scope, it'd be ONE click. If ya run an 1/8MOA scope, that'd be two clicks...

Are you guys actually capable of doping the wind to within 1.25" on either side of the X ring, at 1,000yds? If you can do that, my hat is off to ya...

 

[Ledd Slinger]

How is your velocity by comparison( meaning 52 vs 59 grains) ? My capacity isn't low but not compressed either. I'm running my 284 in a short action gun. My COAL is 2.975. Accuracy is very good but again not sure how this will affect my barrel wear. I've heard RL26 is a good option but then so is H4350/4831.

Basically the same. Right around 3200 fps. Much better ES with RL26 though.

If H4350 is a good option, then RL16 will be a good option as well. I've tested RL16 in 3 rifles and from my results, it is nearly identical in burn rate to H4350. RL17 actually has to be loaded at charge weights slightly lighter than H4350. You wouldn't think 17 would be less charge weight than 16, but that has been my findings in many different rifles where I've used 17 and the 3 rifles I've tried 16. By less, I mean about 1gr. So they are pretty close. Biggest difference is RL16 has the new Alliant TZ temp control technology and is much more resistant to temp changes.

 

[Grimstod]

I was just running the numbers to see how much farther this bullet will go compared to a 140gr and the 140gr goes subsonic at 1650 in my rifle and with the new bullet its 1800.

 

[284winner]

I was just running the numbers to see how much farther this bullet will go compared to a 140gr and the 140gr goes subsonic at 1650 in my rifle and with the new bullet its 1800.

Looks like at around 1000 yards, the 155 begins to take over in velocity. The 140 slows quicker. At least running it at 2800 fps which seems reasonable in a 6.5-284.

 

[Ledd Slinger]

I was just running the numbers to see how much farther this bullet will go compared to a 140gr and the 140gr goes subsonic at 1650 in my rifle and with the new bullet its 1800.

Which caliber, 140gr bullet, and elevation are you using to get those numbers?

The speed of sound is 1116 fps. With my 6.5 Rem Mag pushing the 140gr Berger Hunting VLD at 3200 fps in a 26" barrel, I go subsonic at 1650 yards when calculated at sea level (0 ft). If I calculate it at the 4000 ft elevation where I practice long range shooting, I don't go sub sonic until 1950 yards. Where I hunt up in the 5500-7500 ft elevation range, it goes even further.

I bet I could push that 155gr bullet up around 3050-3100 fps if my 1 in 8" twist would stabilize it because even at 3200 fps with the 140, I'm still not showing any signs of max pressure.