Accuracy of New vs Old Cartridge Designs

[Chris_in_Idaho]

I've seen a lot of reference to "modern" cartridge and chamber/throat designs being more inherently accurate than older designs. What I'm not sure I'm understanding correctly is whether this is referring to older "sloppier" made rifles and walmart tier junk ammo vs newly manufactured rifles and good quality ammo, or is it simply old design criteria vs new even within the same manufacturer and quality level?

For illustration purposes:

If I bought two brand new Tikka T3X Lite Stainless, one in 7mm08 and one in 6.5 Creedmoor, and I bought a box of Precision Hunter 7mm08 150eldx and a box of precision hunter 6.5cm 143eldx, would you expect the same accuracy potential out of both? Or, despite both being from the same manufacturers, same quality levels and product lines, would the 6.5 CM have greater accuracy potential because of it's design and chamber dimensions?

Not a big enough sample size? Ok, 100 of each rifle each shooting a Form-Approved 30 shot group...

Simply looking at 100 yard group size and ignoring other possible benefits like ability to seat longer bullets and ammo availability, do they group the same or does the "modern design" of the Creed result in actual smaller groups than the 7mm08?

 

[100percent]

NO!!!

 

[hereinaz]

In practical terms, not really.

But, modern cartridges have more going for them than the minimal accuracy advantage. Many modern cartridges are designed for the higher BC bullets with faster twists and larger throats.

Brass grows less. Burns barrels less. Loading for modern cartridges with less taper and sharper shoulders are easier.

Look at the choices of winning bench rest shooters where the marginal advantages are common. Short/fat with long necks and sharp shoulder angles. Shorter powder columns seem to burn more consistently.

 

[wapitibob]

I don’t see anybody bragging about 30-06 or 7mag groups.

 

[Formidilosus]

For illustration purposes:

If I bought two brand new Tikka T3X Lite Stainless, one in 7mm08 and one in 6.5 Creedmoor, and I bought a box of Precision Hunter 7mm08 150eldx and a box of precision hunter 6.5cm 143eldx, would you expect the same accuracy potential out of both? Or, despite both being from the same manufacturers, same quality levels and product lines, would the 6.5 CM have greater accuracy potential because of it's design and chamber dimensions?


Simply looking at 100 yard group size and ignoring other possible benefits like ability to seat longer bullets and ammo availability, do they group the same or does the "modern design" of the Creed result in actual smaller groups than the 7mm08?

Given your examples, yes. Overall there will be a difference in precision between than with the 6.5cm averaging better.

 

[willfrye027]

I don’t see anybody bragging about 30-06 or 7mag groups.

Hey now! My tikka t3 30-06 is the most accurate rifle I own and the smoothest action out of all 5 of my tikkas.

 

[Jason Snyder]

Given your examples, yes. Overall there will be a difference in precision between than with the 6.5cm averaging better.

Realistically, how much difference?

 

[TaperPin]

There’s a little improved inherent accuracy potential that is from the case design, all other things the same, but it’s not much. Just look to benchrest records that fell after a new cartridge came along. The difference is very small, but is real.

Most of the “advantage” of modern designs goes away when equally good reamer clearances, handloads, and barrels are used. Before the PRC cartridges were even a wet dream, many of us were shooting accurate rifles that are every bit as capable in old cartridge designs.

We didn’t have the accurate factory ammo that many of the new cartridges benefit from - that’s a good thing and I wish all cartridges would get better ammo. Humans are suckers for marketing - make it “new” and people will buy it. Humans are also surprisingly content to shoot inaccurate rifles as long as it’s a new cartridge design.

In the end I like to see every generation take a step forward and be a little better - the new cartridges are a little better, but I still enjoy the old ones.

 

[100percent]

There’s a little improved inherent accuracy potential that is from the case design, all other things the same, but it’s not much. Just look to benchrest records that fell after a new cartridge came along. The difference is very small, but is real.

Most of the “advantage” of modern designs goes away when equally good reamer clearances, handloads, and barrels are used. Before the PRC cartridges were even a wet dream, many of us were shooting accurate rifles that are every bit as capable in old cartridge designs.

We didn’t have the accurate factory ammo that many of the new cartridges benefit from - that’s a good thing. Humans are suckers for marketing - make it “new” and people will buy it. Humans are also surprisingly content to shoot inaccurate rifles as long as it’s a new cartridge design.

Bingo!
Most of the “advantage” of modern designs goes away when equally good reamer clearances, handloads, and barrels are used.

 

[Chris_in_Idaho]

Bingo!
Most of the “advantage” of modern designs goes away when equally good reamer clearances, handloads, and barrels are used.

Ok, does a new factory rifle like the Tikka in my example above have the same good reamer clearances for old cartridges and new cartridges? Or does the chamber blueprint dictate a sloppy chamber/throat on old designs?

 

[100percent]

Ok, does a new factory rifle like the Tikka in my example above have the same good reamer clearances for old cartridges and new cartridges? Or does the chamber blueprint dictate a sloppy chamber/throat on old designs?

Tolerances around blueprint specs should be consistent across all chamberings in a perfect world…

 

[amassi]

Having had tikkas in 260 rem (boo, old) and 6.5 creedmoor there’s no difference in accuracy
It is a heck of a lot easier getting accurate factory 6.5 cm ammo though.


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[Formidilosus]

Realistically, how much difference?

Given the OP’s parameters- I would expect average 10 round groups from the 6.5cm to be 1.2 to 1.4 MOA, and the 7mm-08 could be anywhere from the same 1.2 to 2 MOA. That would be on average.


The reason that so many (the vast majority) of rifle reviews in magazines and online are in 6.5cm and now newer Hornady cartridges is because they have the highest chance of shooting well with factory ammo.