Load workup Chrono readings

[TheSnake]

Loaded up some starting rounds for my brother for a new bullet. Loaded 5 sets of 3 rounds each to shoot over chronograph for consistency and pressure. Each set .5gr higher than the last. Below are the Chrono readings for each set. I normally load 5 rounds per group but because my brother has limited brass, I only loaded 3 each. My question is this; are 3 rounds enough to make a conclusive decision on the proper powder weight and go straight to seating depth testing or should I shoot more rounds around group #3 below before moving on? Note that I have never hit an ES of zero on the first go round but again this is only 3 rounds and it make me feel more lucky than convinced.

Group #1: 2949 2976 2970 ES=27 SD=14
Group #2: 2976 2976 2962 ES=14 SD=8
Group #3: 2996 2996 2996 ES=0 SD=0
Group #4: 3016 3037 3016 ES=21 SD=12
Group #5: 3058 3044 3044 ES=14 SD=8

 

[Terry]

What do the groups look like? What range were they fired?

 

[Shynloco]

Snake,
Like Terry said, not enough info. BUT personnally I wouldn't rely on only three shot groups. I'd lower the number of groups and increase the number of shots if needed. BTW, what caliber are you shooting?

 

[Erik Cortina]

We can tell you more about accuracy potential by looking at groups than by looking at chronograph readings.

 

[TheSnake]

This is a 300WM, 210gr Berger VLD Hunting bullets, RL22, Fed 215 Primers. I had loaded him up 20 on the low range before hunting season. He sighted in his rifle and used them during the season to take an 8pt. He ran out of rounds and tags so this was the first groups towards finding a good round. We were only at 100 yards and he was doing all the shooting. Rifle is a stock Browning A Bolt under a Nightforce scope. He has had the rifle for many years and no telling how many rounds through it. First few groups of 3 he was sighting it in and the remaining rounds were in a small group for him. All rounds in about 2.5 inches shot on the same target (I know, not much help here). With him shooting them, I was going for lowest ES as my goal. Powder weights were: 73.0, 73.5, 74.0, 74.5, and 75.0. The 74.0 group had the 3 shot zero ES.

Thanks!

 

[Erik Cortina]

Sorry to break it to you, but sometimes low SD/ES mean nothing. Low ES and accuracy don't always go hand in hand.

 

[Catfish]

I have used 3 shot groups at times, but usually shoot 5 shots. I also never get the crono out untill I have found the most accurate load. The ES will make little to no difference in a hunting rifle if the shot are not over 500 yrds. From there on out you will notice more difference in vertical stringing as you work on out.

 

[TheSnake]

Well then I guess I will load up some rounds around the 75.0gr and shoot them myself to see what they will do. Never shot his rifle before so I hope it will shoot halfway decent so I can get somewhere with it. At least he has a brake on it. Thanks for the replies guys.

 

[necchi]

I'd reload #3,#4,#5 at 5 rounds each and shoot for group at separate targets.

From there, select the best grouping of the 3, then mess a bit with seating. Then mess with the powder again in 2 tenths increment's,,,

Trouble is most non-loaders don't have time nor patience to shoot that much. They just want a load better than factory ammo (which is usually easy) and be done with it.
(Heaven Forbid, buying a bag of brass )

 

[amlevin]

As good as Group 3 looks, statistically the numbers are flawed.

The smaller the "sample" the less the "statistics mean".

I would first look at the group sizes and then work around the best.

If you want to determine statistics for the best performing round, then load a couple dozen rounds of the best grouping load and shoot at least 20-25 over the chrono. THAT average speed, SD, ES, etc will mean far more.