Match ammo with lowest standard deviation

[LHH]

Any consensus on which match ammo is the most consistent from a velocity point of view?
Thanks in advance

 

[Terry]

Which caliber?

You will find most of us make our own.

 

[patriot]

If only the rules would allow us to load our own 22 rimfire; would sure save a lot of time and money testing.

In general the more you pay the better the standard deviation. But lately the exception to the rule seems to be the rule. The best I've seen for 50 rounds was Eley Tenex with an SD of 5.2 and ES (extreme spread) of 21 FPS. Runner up was Eley Black Box off a new machine a while back at 6.5/23. I've found several lots of Center X around 6.5/30.

Eley's published velocities are unreliable. A friend recently bought and shot Tenex 1072 for a match without testing. He had high shots and wind problems. I ran 50 of his lot through the CED2 Saturday and the average velocity, measured at 12 feet, was 1096. Ouch! The ammo he had been shooting very well in practice was 1044. I used my best lot of Center X as a control, this wasn't chronograph error.

Mark

 

[LHH]

Referring to 22 RF only.

 

[rvn1968]

Lapua Polar Biathlon,1099, The ammo tests on this site pretty much back it up.

 

[patriot]

Per the JBM Ballistics Calculator, a 40 grain 22 with a muzzle velocity of 1040 drifts 1.1 inches in a 3 MPH wind at 100 yards (NOAA - Light Air - Direction of wind shown by smoke drift, not by wind vanes. Little if any movement with flags. Wind barely moves tree leaves.). The same round at 1099 drifts 1.3 inches. Have that wind fishtail from left to right and the 1099 round has a .3 to .4 inch disadvantage.

There are too many variables to make a blanket statement. Who was operating the machine that day? What machine ran the ammo? How consistent was the priming compound, powder, head space, bullet shape and weight?

The ammo tests on this site were for 25 rounds. This is far too small a sample size. He was also shooting for groups, so the results were influenced by what the rifle liked and not just ammo consistency. For example, the Eley Sport in his test did fairly well. The last batch I tested had an SD of 20 and an ES of 125!

 

[patriot]

I pulled together some Eley, Lapua, SK, Wolf, RWS, and Norma test data to illustrate the point. You roll the dice and take your chances. Below the line you win, above you lose.

Mark

 

[LHH]

Patriot: Nice chart, great explanation.
Which ammo was lowest right data point?

 

[patriot]

Eley Tenex. The best was a box a friend received as a gift after making the Dewar team at the nationals last year. We'd all like to have a case or two of that. But not all Tenex is the same. One lot cost a friend a 1600 (out of 1600) when a shot dropped out the bottom.

Mark

 

[rvn1968]

Nice chart Mark,but I couldn't understand the undefined points. BTW,the tests on 6mmbr were 75 rounds plus fowlers,over 4000 rounds fired.They used a Bleiker,I can't even afford to kook at that gun. It will always be true that every rifle (even Bleiker ) likes what it likes. Tom

 

[patriot]

Is that the same test as on this site? If so, the variability of the rankings between 50, 75, and 100 yards points out the risk in small samples plus group size as a measure is complicated by shooter and environmental influences. There is inherent error with a chronograph too, but I flipped one CED2 upside down inside another to measure it; was more accurate than I expected.

Each point on the chart represents a 50 round test of an ammo brand / lot. Sometimes 50 rounds is more than enough to tell you the ammo is average or worse. The good stuff needs larger samples to increase the certainty. For the RWS 50 I recently tested I ran a 100 round sample.

Mark

http://www.accurateshooter.com/guns-of-week/22lr-rimfire-ammo-comparison-test/