What caused the Rokslide shift to smallest caliber and cartridges?

[jjohnsonElknewbie]

Wind drift in any given chambering is determined by BC- full stop. A lower BC bullet will drift more in the exact same rifle and chambering, than a higher BC bullet.

And to illustrate the point. See .308 comparison below. Both bullets are Berger VLD launched at the same speed. Pay attention to the numbers at 500. Higher BC allows the heavier projectile with the same MV to carry higher velocity at range, decreasing drop and drift over the lighter bullet across the full trajectory.

 

[Squincher]

• Sub-100 grain goes for the .223
• 108-115 are absolute hammers for .243 and 6mm (some guys have great results with 90-100 as well)
• 100-135 are absolute hammers for .25 (some guys have great results with 90-100 as well)
• 120-156 are absolute hammers for 6.5

There is a huge difference between "suitable, decent, satisfactory" and "ideal". The point and the "why" is to shoot a cartridge/bullet that provides the best combination of wound channel, trajectory, recoil, and overall cost (components, rifles, etc...). All of the calibers above perform at least as-good and most often better in these areas as anything larger. This isn't a generational debate at all. I'm 48 (Gen-X) and after swallowing my pride and reading the data and looking at the field results was eager to get on the train.

There will be a different train along in a little while.

 

[mt terry d]

So what is everyone’s plan for all the other calibers they own? It seems like the .223 77 tmk is as good as it gets. Are people going to start dumping their larger caliber rifles? Just let them sit in the safe? Seems like the only issue with the .223 setup would be minimum caliber restrictions in some states. If the future is small caliber and maximum efficiency bullets, will there be any reason to keep using large caliber rifles and traditional hunting ammo?

I have a 7mm wby mag that has killed the bulk of my big game for the last 40 plus years and has sentimental value which I'll keep and pass down to my kids

I also have a Browning A-bolt stainless synthetic , 26" bbl 300 Win mag that I killed an Alaskan Moose and caribou, along with a bunch of reloading stuff/brass that will be sold when I get around to it.

 

[Bluefish]

BC isn't a factor for most hunting ranges, but even still, drop decreases with increased speed. Therefore, if you went from 180 to 130 gr, the starting velocity is much more so the drop isn't a factor until you get to very significant distances. Also, velocity is important compared to diameter, so even though it's a short fast bullet, it's still not that effected by wind either.

I disagree that bc doesn’t matter at short ranges. While drop and wind drift won’t change much, the velocity can be a lot lower than expected due to poor BC. I never gave it much thought until I started looking at LabRadar data. Suddenly a bullet I was testing was dropping 500+ fps in less than 100 yards. I looked at the data and was confused how this could be happening. Then I back calculated the BC by comparing actual velocity to predicted. Turns out that bullet had a bc of .15 ish (35 cal 200g). Suddenly my down range velocity meant that my range was not what I had expected If I wanted to keep the bullet inside it’s working velocity (2200-1400). Mv was 2300 which suddenly limits that bullet to about 150 yards and still open.
I started to look at BC vs MV, vs velocity on target and minimum velocity for the bullet. this along with the push to smaller diameter cartridges and heavy for caliber all started to come together to really illustrate how it’s all about delivering the bullet at the right velocity to do its job. do that and you have a clean harvest.

 

[Squincher]

And to illustrate the point. See .308 comparison below. Both bullets are Berger VLD launched at the same speed. Pay attention to the numbers at 500. Higher BC allows the heavier projectile with the same MV to carry higher velocity at range, decreasing drop and drift over the lighter bullet across the full trajectory.

View attachment 634566

Now show two bullets of the same BC driven at different velocities. Think the drift will be the same?

 

[jimh406]

If you are saying that using the same design parameters one can get a larger bullet to make a bigger wound- sure. But to what purpose? Sub 100gr bullets are already creating too much tissue damage- that is they kill too well.

...

I am confused of what you are trying to say? Wind drift in any given chambering is determined by BC- full stop. A lower BC bullet will drift more in the exact same rifle and chambering, than a higher BC bullet.

I'm simply saying that you can do the same thing with a large diameter as a small diameter bullet. I don't have a purpose other than to point that out. Btw, the ideal is to kill just enough, but I don't think anyone knows how dead is just right.

My point is that BC is a factor used to calculate the relative wind drift and drop if the weight and velocity is the same. There are three inputs to wind drift and drop: weight, BC, and velocity. None are independent of the other.

 

[fwafwow]

I think the shift is somewhat attributable to every generation thinking it has a better idea, combined with Gen Z wanting to go to the opposite extreme of boomers on every issue. The fact is 130-180 grain bullets driven at standard velocities have always been suitable for everything in North America. But since the boomers went with big magnums as their "better idea," Gen Z has to go with sub-100 grain bullets as their protest. Some future generation will eschew the practice of using the lightest bullets for purposes for which they were not intended, and shooting at ranges that require the hope your quarry won't turn or step between the time your brain can't stop the trigger pull and your bullet reaches the target, or that a slight gust of wind a quarter mile away won't turn your shot into a marginal or bad hit. Through all the trials and tribulations, though, 130-180 grain bullets driven at standard velocities will still be the sweet spot.

FWIW, I'm Gen X but have switched my viewpoint due to peoples' pictures and analysis. Not in protest. And if someone comes up with better analysis and support for another method, I'm open to hearing it and changing my mind - again.

A few thoughts. First, one point to the "RS shift" is that even if a particular cartridge and bullet weight could be suitable, that doesn't necessarily mean it can't be improved - for a situation or shooter. Second, I don't think that there is any push that this "new way of thinking" is limited to sub 100 gr bullets. The 140gr TMK in 6.5 CM is an example. Third, I'm not sure about the "for which they were not intended" comment, as the "match bullets" are inferior to "hunting bullets" has been addressed numerous times. And finally, as far as ranges and speed in relation to an animal moving, I think that the "RS shift" is not limited to LR hunting, and the risk of animal movement or wind shift is present with any caliber or bullet, but probably reduced for the high BC projectiles that are being used.

 

[jjohnsonElknewbie]

Now show two bullets of the same BC driven at different velocities. Think the drift will be the same?

As requested and of course the drift will be different with the same BC. That wasn't the argument.

 

[jjohnsonElknewbie]

FWIW, I'm Gen X but have switched my viewpoint due to peoples' pictures and analysis. Not in protest. And if someone comes up with better analysis and support for another method, I'm open to hearing it and changing my mind - again.

A few thoughts. First, one point to the "RS shift" is that even if a particular cartridge and bullet weight could be suitable, that doesn't necessarily mean it can't be improved - for a situation or shooter. Second, I don't think that there is any push that this "new way of thinking" is limited to sub 100 gr bullets. The 140gr TMK in 6.5 CM is an example. Third, I'm not sure about the "for which they were not intended" comment, as the "match bullets" are inferior to "hunting bullets" has been addressed numerous times. And finally, as far as ranges and speed in relation to an animal moving, I think that the "RS shift" is not limited to LR hunting, and the risk of animal movement or wind shift is present with any caliber or bullet, but probably reduced for the high BC projectiles that are being used.

 

[Squincher]

FWIW, I'm Gen X but have switched my viewpoint due to peoples' pictures and analysis. Not in protest. And if someone comes up with better analysis and support for another method, I'm open to hearing it and changing my mind - again.

A few thoughts. First, one point to the "RS shift" is that even if a particular cartridge and bullet weight could be suitable, that doesn't necessarily mean it can't be improved - for a situation or shooter. Second, I don't think that there is any push that this "new way of thinking" is limited to sub 100 gr bullets. The 140gr TMK in 6.5 CM is an example. Third, I'm not sure about the "for which they were not intended" comment, as the "match bullets" are inferior to "hunting bullets" has been addressed numerous times. And finally, as far as ranges and speed in relation to an animal moving, I think that the "RS shift" is not limited to LR hunting, and the risk of animal movement or wind shift is present with any caliber or bullet, but probably reduced for the high BC projectiles that are being used.

Could be. Just strikes me as the opposite side of the big magnum coin. Both work, but the best spot is somewhere in the middle.

 

[jjohnsonElknewbie]

I'm simply saying that you can do the same thing with a large diameter as a small diameter bullet. I don't have a purpose other than to point that out. Btw, the ideal is to kill just enough, but I don't think anyone knows how dead is just right.

Sure you can, at the expense of:

More powder
More muzzle blast
More recoil
Lower hit %

 

[Formidilosus]

Could be. Just strikes me as the opposite side of the big magnum coin. Both work, but the best spot is somewhere in the middle.

How do you know that is best spot? And what metric are you using to determine that?

 

[Squincher]

As requested and of course the drift will be different with the same BC. That wasn't the argument.

View attachment 634583

What do you mean that wasn't the argument? Didn't someone post "Wind drift in any given chambering is determined by BC- full stop."

 

[Mike Islander]

And I own a 6.5CM which was purchased due to cheaper ammo, less recoil, availability, etc.

That's enough for many people. Fact is, magnums are unnecessary and expensive. Less noise and less recoil = significantly more accurate shots for most people, as well as enabling follow up shots.

This is not new. Long before Form burst forth on Rockslide to show actual evidence and to speak from undeniable experience, guides and governments have been very emphatic that you should "shoot what you can accurately handle instead of large magnums that make you flinch".

High BC bullets also contributed, since it enabled those same small, effective loads to carry killing ability much further than most can ethically shoot.

The fact that a little 77 grain TMK is shockingly effective brought a ton more folks over, since .223 is dirt cheap to buy and dirt easy to shoot.

 

[jjohnsonElknewbie]

Could be. Just strikes me as the opposite side of the big magnum coin. Both work, but the best spot is somewhere in the middle.

Then the 6.5 Creedmoor or .270 are perfect for you.

 

[jimh406]

Fact is, magnums are unnecessary and expensive.

I'd just like to point out that some of us hunt where there are animals with teeth and claws. . You might feel comfortable with a .223 in that case, but others may not feel their magnum is "unnecessary".

 

[Formidilosus]

I'm simply saying that you can do the same thing with a large diameter as a small diameter bullet. I don't have a purpose other than to point that out.

This is where it gets confusing- literally everyone discussing this knows that. We are literally having a conversation about about sunrise and sunset, and you are stating that the sun rises in the east… ok?

My point is that BC is a factor used to calculate the relative wind drift and drop if the weight and velocity is the same. There are three inputs to wind drift and drop: weight, BC, and velocity. None are independent of the other.

What are you trying to say? Clearly stated- in any given chambering, the higher BC bullet will have less wind drift than a lower BC bullet when loaded to like pressures- from the same exact gun. A 130gr .308 bullet with a .350 G1 BC loaded max pressure in a 308win will drift more in wind, than a 175gr bullet with a .495 G1 BC when loaded to max pressure. There is no version in the same cartridge where decreased BC but increased MV results in less wind drift.

 

[Squincher]

How do you know that is best spot? And what metric are you using to determine that?

I'm aware of what has happened more than five years ago, and my metric is those cartridges kill everything without being on the fringe of bullet performance.

Then the 6.5 Creedmoor or .270 are perfect for you.

You are a man (I assume) of true insight. I just made an impulse purchase of a Model 70 Featherweight in .270 Win.

 

[Formidilosus]

I'd just like to point out that some of us hunt where there are animals with teeth and claws. . You might feel comfortable with a .223 in that case, but others may not feel their magnum is "unnecessary".

“Feel” is the problem. Feelings lie. The only reason people “feel” that a magnum is better for teeth and claws is because they have been told it is, not because of rigorous testing or empirical evidence comparing all the actual e options, but because of dogma that was never put under scrutiny.

 

[jjohnsonElknewbie]

What do you mean that wasn't the argument? Didn't someone post "Wind drift in any given chambering is determined by BC- full stop."

Nice try. Maybe use the full quote next time bud.

I am confused of what you are trying to say? Wind drift in any given chambering is determined by BC- full stop. A lower BC bullet will drift more in the exact same rifle and chambering, than a higher BC bullet.

Exact same chambering meaning same MV.