New load help

[Dt219]

[Constitutionalist]

The last step is showing a little bit of a spike in velocity which would indicate you're getting close to high pressure but aren't necessarily there yet. It looks like there's an accuracy node around 28.5gr. How big was the group?

[Klem]

Dt,

It all looks normal.

If you graph the relationship you can see a linear progression all the way to the top. 28.7 is the odd one out but that is less velocity, not more. Something not right about that; either the chronograph or your loading, or recording. Perhaps one of the three shots was awry and it pulled the average down. Regardless the max load is directly in line with all the other loads and the bump is the opposite to what would otherwise concern us.

QL also predicts your case at 100% full at the max load. This means you have not yet gone into compressed load territory so it is unsurprising there is a predictable linear climb. It is also predicted that you are right on SAAMI max so I would be reluctant to go any higher. You will eventually break a bolt if you do. The computed velocity prediction is also pretty close to what you got.

You can use any of those loads.

[Dt219]

[Klem]

Why don't you repeat the three shots at 28.5 to confirm whether that dip in the graph is an aberration or not.

I don't use Satterlee given the clumsy correlation between velocities and group size. Other things are happening to the gun which velocity is not indicating. For example as the barrel whips it can be pointing in different directions regardless of muzzle velocity.

[Dt219]

[Harpoon1]

I don't use Satterlee given the clumsy correlation between velocities and group size.

https://youtu.be/WSSaiX7akaQ

[Klem]

Correct, the one that dips, it's only 3 more bullets in your work-up system so no sweat checking it that way. Otherwise we are jumping to conclusions.

Interesting you mention "new methods" and Satterlee as being something you are prepared to try, but not a ballistics program. Quickload predicted your muzzle velocity to within 10fps. I am not advocating using it to the exclusion of other sources of data; instead, it complements them for greater confidence and saves money. You might find it works better than Satterlee.


Harpoon,

Once you start exclusively using Satterlee then it's akin to a religion. People get nervous when their faith is challenged. I posted empirical data (evidence) on an earlier thread where we discuss Satterlee and I outline my reasoning why it doesn't work. As for you guys using it, knock yourselves out with my blessing (pardon the pun). You swear by it and I think it is rubbish - Ce la vie.

[Dt219]

[A5BLASTER]

If it was me.

I would load 5 rounds at 28.5 grains and rerun them on the chronograph.

If the sd/es numbers came back low like that again. Then I would start working on my bullet seating depth. 5 shots at each new coal length. Changing coal length in 5 thousands between each 5 shots.

Sd/es numbers first, searing depth second. It's what works for me and my sub moa loads and my rifles.

[TropicalVibe]

[Klem]

Of course it doesn't, but you know that. QL is an internal ballistics predictor, not an external results predictor. Satterlee is a results predictor, and is the only one out there that claims to predict long range group sizes by muzzle velocity (only). There is an implied veracity to metrics and graphs that belie their true ability to predict results. My point is, it is seductive to think that graphing a few chronograph readings will tell with certainty what is going to happen down range - be careful.

If shooting at long range targets when doing a work-up is inconvenient or logistically impossible then that is unfortunate. I am in the same boat. I can't shoot past 400M without going to some cost and effort. So, in both our cases we are hoping to predict what happens at long range based on what happens at short range. In my case I prefer to see results on targets, augmented by a chronograph. With just a chronograph you are taking a bigger risk and that requires faith.

Bottom line, none of us can be certain we have settled on the best load if we never test all loads equally at long range.

[RiverRider]

In my opinion, a chronograph is great for one thing, and that is to acquire some kind of clue as to what chamber pressures you're getting---in the interest of safety. A secondary benefit is to spot problems with ignition due to insufficient powder charge or primer deficiencies and other things of that nature.

I agree with Klem's preference to see the results on targets. At the end of the day, that's what you're after. There are just too many variables affecting accuracy to put so much emphasis on chronographed velocities---including the chronographs themselves.

[StoneHendge]

I usually stay out of this one, but the time has come. Satterlee is pointless because it has no statistical significance. If your looking for the "golden node" that indicates velocity stability, you could easily be an area where there is none, have one shot (or small set of shots) be a deviation high followed by a shot (or small set of shots) that are a deviation low making one think they have found the holy grail only to be sent on a wild goose chase. Conversely, one could miss their "node" if they have an outlier on the wrong side. The method also assumes there is a very strong statistical relationship between velocity consistency and two dimensional dispersion. I'm sure the relationship is positive, but I've come across plenty of loads in development with great SDs that grouped like buckshot and loads with great accuracy with high SDs.

Nothing beats good old fashioned five shot groups shot over a chrono in 0.2 to 0.3 grain steps. A bullet and powder combination either gives you a charge where it groups well with a low SD above a velocity threshold you are looking for or it doesn't. One visit and you know if your onto something. Fewer range trips required. Savings on range fees and gas.

My initial thought on seeing the OPs initial results was try another powder if the accuracy wasn't there. Upon hearing that the dispersion was vertical at 28.5 gr, I wonder if shooter error might have come into play (inconsistent bipod loading or inconsistent shoulder placement if shot off of bags).....

[Harpoon1]

I'm sure the relationship is positive, but I've come across plenty of loads in development with great SDs that grouped like buckshot and loads with great accuracy with high SDs.