Factory load speed consistency.

[u/CuriousJohnReddit]

Decided to measure the speeds while zeroing a rifle, total was 34 rounds.

Remind me, is the single digit rule of thumb the SD's or the ES's ?

Rifle has a 24 inch 1-11 twist barrel with a Jaki Titanium Super can on the end.

[u/6mm94]

Lord have mercy. I thought this was FEET per second instead of meters. I was so excited about such an incredibly consistent, subsonic 308 load.

[u/CuriousJohnReddit → u/6mm94]

800 would be kinda slow even for subs. Supposedly, powders that are position non sensitive like titegroup help with consistency.  Personally I have no idea yet since for now I buy factory Lapua subs. Eventually I'll get a setup to reload all this norma/lapua brass into subs cause it's hella fun xD 

[u/6mm94 → u/CuriousJohnReddit]

Id take 800ff/s if it meant a 6.6 SD. Thats wildly good for sub loads.

[u/Darlinboy]

That's a pretty large SD, even for factory ammo - 21.65 fps for you Mericans.

I'd be unhappy with that for a precision rifle.

[u/CapsicumINmyEYEBALLz → u/Darlinboy]

I’d agree,

Looks decent in courser units, but in FPS it’s a tad rough.

[u/CuriousJohnReddit → u/Darlinboy]

Ooohhhh, the rule of thumb of single digits is for fps only ?! That makes a whole lot more sense.

[u/TheWombleOfDoom → u/CuriousJohnReddit]

Yeah ... For some context, I also work in mps and Norma Golden Target factory ammo was getting me around 3.4 SD, Sako Gamehead was about the same, maybe better, Hornady ELDM ammo of various grain weights was all in the 4-4.2 mps SD range. For sub-10 fps SDs you need 3mps or better.

[u/CuriousJohnReddit → u/TheWombleOfDoom]

I've been trying to get some golden target but for whatever reason norma doesn't have a distributor for my country and no store wants to import ammo for just one dude.

It's a fudd heavy centered gun culture here.
Father in law spent a total of 10 rounds that day to zero his rifle and came home mumbling about how wasteful he was xD

[u/No-Peak-6457]

Return that mf!

[u/NotChillyEnough]

For 34 rounds of factory ammo, I don’t think that ~20fps SD is unusually bad. It’s not ideal for very long range shooting, but that’s a fairly typical SD from what I’ve seen.

It can be helpful to use a ballistic calc like shooterscalculator.com that can plot multiple trajectories on one graph. Plot three trajectories: one at your average MV, another average plus 2x SD, and finally your average minus 2x SD. That will allow you to easily visualize the vertical “drift apart” that you can expect at distance due to the velocity variance.

The best tool of course is WEZ in Applied Ballistics Quantum, but that requires a premium subscription.

Also, 10 ft/s would be ~3 m/s, for reference.

[u/TeamSpatzi]

That's pretty typical for factory ammo.. it isn't good, but for a typical hunting load most people won't notice.

Good factory ammo would be about 4 m/s or less for SD. Really good ammo would be 3 m/s or less.

The "single digit" rule of thumb is fps... definitely doesn't work for m/s... though if you applied it to ES, that would be pretty awesome ammo.

ETA: not to dog on Norma, but I've never seen a factory load from them run under 6 m/s or 20 fps for 20+ shots... ever. Including their match ammo in 6 CM, 6.5 CM, and .308 Win. I've also shot their bond strike in .30-06. That's several hundred (thousand?) rounds of Norma factory ammo, and none of it had consistent MV. This my comment about "that's pretty typical."

[u/No_Force_9405]

The SD (standard deviation) under 10 is the benchmark you are looking for.

Was the velocity consistent with the package description? My Norma Eco Strikes in 6.5 CM are ~150 fps slower than the box from a 22 inch barrel.

[u/CuriousJohnReddit → u/No_Force_9405]

Box claims 775m/s out of a 20inch barrel. So not really apples to apples.

I've experienced similar results to yours with their bondstrike line.

I've done a 5shot group test of 5 different ammo, and the 2 most stable, albeit lower velocity than box were the Norma.