The "Most Accurate" Cartridge

The "Most Accurate Cartridge"

By Andries

The moment a bench rest shooter wins a competition having used a cartridge with a slightly different geometric case design all the losers blame their old tools for not having won the competition. Suddenly the new 6 millimetre with a 37.3 degree shoulder angle and no case taper and 47.7 or whatever millimetres in length is the most accurate cartridge and bullet diameter combination. (In the bench rest religion using the term point two four three inches, or point two six four inches is sacrilege - the BR Faith is measurement in metric units).

That following year everybody and his dog will buy and load for this new BR wonder. But at the next shoot there shockingly still is only one winner... That #1 position may again be held by the same expert shooter with his same whatever BR case. The top position will not be shared by the 143 religious followers who had bought the same chambering as the previous year's winner. And the winner again is not announced in the media as the shooter - the cartridge is. Beatified by gun writers the cartridge (called "calibre" in US gun writing) used by the best shooter receives the accolades and not the skilled shooter. Expensive tools do the job and not the skill of the craftsman, it seems.

But: we know that ***t happens - and maybe a shooter using a new, another slightly different case shape wins the competition this time (his rifle's chamber still designated in US metric measurements - not a boring full metric non-entity called a 6.5x48,8 mm, no sir. The lone, affluent English-outback sounding "Six Point Five Creedmoor" from now on will be all the rage). A lordly name is afforded a distinctly stepped down version of a popular Swedish military cartridge that is well known in Europe and Africa for being shot very accurately by skilled marksmen from very well made and accurate rifles. Or seen otherwise, its necked down from an old, forgotten USA case which was savagely fast in its heyday. The Creedmoor may be a slight step down from the 6.5x51 (.260 Rem) and 6.5x55 and 6.5x57 and 6.5x58 and a huge step down from the German 6.5x68S), but it has a deep sounding moniker and therefor it is assumed to be magical.

Soon in gun forums the Creedmoor would be written as "Creedmore" which makes it sound even more impressive. And like forum posters are wont to do - in order to show an intimate familiarity with the new, impeccably conceived wunderkind of the Shooting Faith it becomes fashionable to fondly refer to it as "The Creed" (which by definition means "a system of religious belief; a faith, religion, religious persuasion, religious conviction, religious group, religious affiliation, religious sect, religious following, religious communion, religious order, religious fraternity, religious brotherhood, etc").

So, is the 6.5x48.8 Creed a more accurate cartridge than the 6.5x55 Swede, or the 6mm Remington, or the 6mm Winchester? Or the 6.5x51 Remington? Or the three 7mm Remingtons? Or the 6.5x57 Mauser? Or the 6.5x58 Portuguese? Or the 6.5x68 Schuler - or the .375 H&H / 9.3x62 Bock / 7.62x63 Sprg / 7.62x51 NATO/ 6.8x64.5 Win / 7.62 Win Mag?

No, it is not. No single rifle cartridge is inherently more accurate than any other. They are ALL inherently exceedingly accurate.

If not the geometric shape and size of the gas generator chamber, what then causes accurate or inaccurate bullet behaviour?

Accuracy does not reside in the size and shape of the gas generator chamber. Prior to, during, and immediately after that explosive combustion and gas release, for the concentric movement of the bullet out of the case mouth and into the barrel throat, its concentric engagement of the rifling, concentric passage through the bore, its 100%, perfectly concentric disengagement from the rifling - each time, shot after shot at the exact same repeated pressure force - it will have not received an Iota of influence from the size and geometric shape of the gas generator.

If the gas pressure generated by the gas generator is exactly the same each time, the time interval from ignition to muzzle departure will also be exactly the same, no matter the shape of the gas generator, and the bullet will exit at the exact same position of the barrel torque-whip.

Accuracy is based on four things and these four things only:

80% probability of all inaccurate shots. The consistent skill of the shooter to have the muzzle bore centre point within one half-thousandth of an inch, shot after shot after shot the moment the bullet disengages from the rifling.
10% probability for divergent groups. The 100% total mutual concentricity and perfect linear alignment and contact of every removable interface of the rifle's components.
9% probability. The 100% total concentric crown of the muzzle bore to release the bullet perfectly nose-bore-centre-aligned.
1% probability. 100% repeat-ability of the interactions between the bullet's inertial and aerodynamic moments during flight.

A repeated, objective test that every year reaffirms the fact that ALL hunting rifle cartridges are created equal

Imagine the following scenario:

Winchester, Remington, Federal each hosts a 110 yard, ONLY bona fide hunting rifle group shooting competition at their testing ranges. Before the event the following information goes out for presumptive competitors:

Only standard hunting rifles are allowed in the following calibres, maximum barrel 26 inches, no bull barrels, maximum rifle weight 13 lb:

1. 222 Rem 55gr.
2. 223 Rem 55gr.
3. 22-250 Rem 55gr.
4. 243 Win 80 / 100gr.
5. 25-06 Rem 120gr.
6. 270 Win 130 / 150gr.
7. 308 Win 150 / 168 / 180gr.
8. 30-06 Spring 150 / 168 / 180 / 220gr.
9. 300 Win Magnum 180 / 220gr.
10. 300 H & H Magnum 180 / 220gr.
11. 303 British 150 / 174gr.
12. 375 H&H Magnum 300gr.
13. 6 mm Musgrave 100gr.
14. 7x57 Mauser 150 / 170gr.
15. 7x64 Brenneke 150 / 170gr.
16. 7 mm Rem Mag 150 / 170gr.
17. 9.3x62 Mauser 286gr.

Only one supplied sand bag front rest is allowed and a maximum 12X scope may be used. Three targets can be shot with three different cartridges, one three-shot group per target. One minute is allowed for three shots. The best group of the three will be entered for the personal competition. One barrel fouling shot is allowed off your target.

In order to qualify to compete: during the 12 months before the event you must have attended at least three officially recorded shoots at your club with only the manufacturer's commercial ammunition - no hand loads. The average group of the three best shoots with the same rifle(s) you will use at the competition must be .5 MOA or better.

At the day of the competition the shooter will be issued with four marked rounds of his hunting calibre(s) at the range when registering. There will be ammunition for all the calibres that had qualified and the buyer can choose his bullet weight.

Now:

Will Remington and Federal and Winchester have the product confidence to host such a competition based on the qualifying .5 MOA maximum group?

How many hunters in the USA will qualify with a yearly average of .5 MOA with commercial ammunition and their hunting rifles and only a simple sand bag front rest?

What would the winning group size be at the competition?

Which of the mentioned cartridges does the reader guess would the final winner have used, and which cartridges would be the likely runner ups?

Based on the opinion that that some cartridges are more accurate than others - which of the cartridges would not have a hope to win or even qualify?

Here are results from just such national competition hosted annually by the South Africa PMP hunting rifle ammunition manufacturer:

About 800 shooters qualify yearly with a .5 MOA club average. The competition venue can not accommodate that number of contestants so only the top130 normally are invited to attend. These shooters will typically have smaller than .40" club averages. Even though rifle calibre is no big deal in these competitions as all cartridges are more accurate than the best shooter is, underneath is a list of the top twenty-five cartridges out of the 130 finalists of a randomly selected competition:

Cartridge

1. 30-06 Springfield

2. 243 Winchester

3. 7x57 Mauser

4. 308 Winchester

5. 308 Winchester

6. 308 Winchester

7. 308 Winchester

8. 308 Winchester

9. 308 Winchester

10. 270 Winchester

11. 7x57 Mauser

12. 7x57 Mauser

13. 308 Winchester

14. 7x57 Mauser

15. 270 Winchester

16. 270 Winchester

17. 308 Winchester

18. 243 Winchester

19. 375 H&H Magnum

20. 270 Winchester

21. 22-250 Remington
22. 7x64 Brenneke
23. 303 British
24. 222 Remington
25. 22-250 Remington

Group

.030"
.130"
.170"
.173"
.177"
.190"
.201"
.210"
.213"
.214"
.230"
.232"
.237"
.240"
.248"
.257"
.258"
.259"
.260"
.270"
.273"
.287"
.291"
.292"
.293"

Just because American gun owners like such statistics - The numbers of each cartridge amongst the top 25:

1. .308W: 8

2. 7x57 4

3. .270W 4

4. .243W 3

5. .22-250 Rem 2

6. .30-06 1

7. .375 H&H 1

8. 7x64 Brenn 1

9. .303 Brit 1

There is no such thing as one cartridge being more accurate than another. The year after this the same winner shot the same size group with his 9.3x62 and the year before he used a .300 Win Mag to win with a .028" group. At his first attendance he shot a second place .100" group with his .308W. The first prize always is a $3,000 hunting rifle/scope combination and he has decided to shoot every next competition with the rifle he had won in the previous competition. He still wins each time - not because of the superior accuracy of the cartridge he chooses to use, but because this guy can shoot accurately.