Thread: Frustrating arvo at the range. Powder charges.

Originally Posted by Snowgrass

My initial concern is why there was a difference in average velocities between the 24gr loads today and the ones from a few weeks ago, all else being equal.

Essentially because 24gr is not a powder weight that gives a stable velocity node. Statistically, You could shoot it again tomorrow and get the original low SD’s, or it could be twice as bad. Doing the ladder test will help identify a stable velocity node.

Originally Posted by Snowgrass

The other bug bear is not knowing what accuracy effects having the magnetospeed hanging off the suppressor is having. Just means having to double up on loads I guess.

The magnetospeed will definitely have an impact on the harmonics and therefore accuracy. So yes, you’ll need to run the seating depth test twice, first without the MS shooting for groups, then again with the MS to record velocities and SD’s.....or borrow a Labradar (a ball ache in itself to use at times).

Originally Posted by gqhoon

Essentially because 24gr is not a powder weight that gives a stable velocity node. Statistically, You could shoot it again tomorrow and get the original low SD’s, or it could be twice as bad. Doing the ladder test will help identify a stable velocity node.

The magnetospeed will definitely have an impact on the harmonics and therefore accuracy. So yes, you’ll need to run the seating depth test twice, first without the MS shooting for groups, then again with the MS to record velocities and SD’s.....or borrow a Labradar (a ball ache in itself to use at times).

Brilliant, thanks for that explanation. What are the common issues with the Labrador?

Originally Posted by gqhoon

Respectfully, you haven’t followed Cortina’s method, so you shouldnt be surprised that you’re getting different results.

Starting again, load from 22.0 to 24.0gr in 0.2gr increments. Only 1 round at each weight. Seat projectiles to mag length or 20 thou off jam. Shoot over a chrony and record velocity.

Use ChronoPlotter to plot the velocities against powder weight and look for flat spots as per the graph below.
Attachment 195381

Selecting the middle of the flat spot, run a seating depth test starting at the depth used in the powder charge test above, and seat progressively shorter CBTO at 3 thou increments. Shoot 3-shot groups and record velocities. Look for where both small groups and low SD coincide. That’s your load.

Thanks for that, its the simplest and best explanation of the EC approach I've seen...

@Snowgrass I saw in your original op that you said you would go off and buy some electric scales.
Save the cash and just get your self some Hornady Beam scales. https://www.hornady.com/reloading/pr...nce-beam-scale
Really accurate and good valve for money. You wont have to worry about them turning off half way through a load and then you need to re-zero them etc

There is a whole thread in here where people complaining abut electric scales.

Anyway good luck with the loading.

Originally Posted by Snowgrass

Brilliant, thanks for that explanation. What are the common issues with the Labrador?

Every Labradar users experiences seem to vary considerably. Unfortunately, my experiences is that it has to be precisely aligned with the direction of the shot (or across the path of the shot) in order to register the shot. Often I’ll fire 5 rounds just to get it aligned and recording consistency, but even then there is no guarantee it will register every shot. I’ve used the microphone and now a recoil activated trigger and while it has improved things, it can still drop shots.

Also, the interface to your phone or tablet is clunky and not refined. Often drops connection and you wonder if it’s picked up the shot. In this day and age, they should be able to do better.

Am not trying to bag the Labradar. It’s a good product but is let down by the quirks of the system. If you can work around the quirks, then great.

Have a magnetspeed also and it’s great for quick set up, 100% reliable etc, but you can’t shoot for groups with it attached to the barrel.

I’ve run Both Labradar and MS together and record no more than 7fps variance between the two systems.

Originally Posted by dannyb

@grandpamac the Cortina method basically works on the theory you can tune any load by adjusting seating depth.
So basically do a charge weight ladder find you most consistent velocity node (lowest ES) then do a seating depth ladder to tune for accuracy.
I have never loaded for 223 so was waiting to see if anyone more experienced chimed in.
This method is championed by longrange pro shooter Eric Cortina and certainly he gets results, as have I but my experience is limited to 270win and above calibers up to 7mm rem mag.
Eric suggests not shooting your charge weight ladder at paper so as not to be suckered in to choosing a load that shoots a small group but has a large ES as this will likely be less accurate at long range due to the variation in velocity increasing exponentially the longer the range and therefore increasing group size.
Eric shoots PRS and bench and shoots some incredible groups out to 1000yards.
What I really like about his method is that he explains it in a way that made sense to me, I first started watching his videos when I was starting out in hand loading so a lot of the terminology was foreign to me Eric explains a lot in layman's terms which was easier for meto understand.
It's not for everyone and in reality is that level of precision even nessacary for a 223 with a max range for medium game well inside 500yards (my opinion no offense to anyone else) probably not. But it sure is fun and when you can understand what's happening and interpret what your group sizes are telling you it's quite fun.
Obviously there are loads of other variables that can be eliminated as mentioned above by @Friwi but again is it really needed for a 223, I wouldn't have thought so.

Thanks @dannyb,
I had a better look at the Audette method. It was as I suspected a series of single shots on paper at 300 yards or longer range to detect shots that were closer together in elevation. He was looking for harmonic convergance where the barrel vibrations compensated for vertical dispersion from the velocity differences from load to load. Crieghton Claudette was born in 1920 and died in 1992 and was for a time the Palma Match Captain so the method was probably developed by him and others in the 1950 to 1970 era. its strength is that it focusses on likely accuracy at range directly and its weakness was that it needed to be fired at longer range. The Palma Match is shot at 800, 900 and 1,000 yards or thereabouts so it is likely Crieghton tested at one of those ranges. Eric basically substitutes velocity for elevation which can be tested at short range. This is looking for flat spots in the progression of velocity together with smaller ES. Thanks danny this has got my mind going on this one and I think some tests are in order.
Regards Grandpamac.

Have used the EC method and gotten consistently great results. As others mentioned it makes a lot of sense, the one thing I’d say is you have to be extremely OCD about charge weight. Like single kernel OCD. I’ll use a digital scale to get to my target weight, then confirm on balance beam and weigh it 2-3 times on that to be certain.

Once I’ve got a load in the teens ES wise (typically 10-15 ES) then seating depth test from there.

Have ended up with quarter/half minute groups consistently out of a Ruger American Hunter in 6.5CM shooting prone off a pack, so for me it definitely works.

Have upgraded to a new rifle and will be using the same method to develop a load for it.

I would not throw your old scales out without checking them.
A balance scale should be more accurate than an electronic as it is not affected the same by baro pressure, elevation etc., gravity being equal on the balance weight and on the powder.
What I would do is take it into one of the scale certification companies, or Avery etc. They will have test weights that are perfect. If your scale is correct with their test weights why replace it ?. For very fine calibration checks I would ask a jeweler which company certifies their scales.

PS can anyone explain why the word 'Balance' is not Balanced, drives me crazy only using one 'l'?

you only need a single projectile......as a test weight...it matters not a huge deal if its supposed to be 50 grns and is 50.005 or some such,you will never notice it...in fact if its 50.5grns it still doesnt matter if all you use it for is to check scales ARE THE SAME AS LAST TIME YOU USED THEM..... eg when the projectile is in pan,set wee sprung screw till balance beam SAYS 50 grns...... and place projectile back in special place till next session.....next time do same again...you starting out with scales zeroed the same way so your powder weights will all be the same....if they a 10th of a grai neither way from what you think...it matters not AS LONG AS THE SAME EACH TIME......

Originally Posted by Micky Duck

you only need a single projectile......as a test weight...it matters not a huge deal if its supposed to be 50 grns and is 50.005 or some such,you will never notice it...in fact if its 50.5grns it still doesnt matter if all you use it for is to check scales ARE THE SAME AS LAST TIME YOU USED THEM..... eg when the projectile is in pan,set wee sprung screw till balance beam SAYS 50 grns...... and place projectile back in special place till next session.....next time do same again...you starting out with scales zeroed the same way so your powder weights will all be the same....if they a 10th of a grai neither way from what you think...it matters not AS LONG AS THE SAME EACH TIME......

good idea, perhaps take some projectiles and get them weighed on a certified scale and pick one that is exactly 50 gr, so that the reference weight is correct. If you had three then the scale could be checked over a range of measurements.

Just a suggestion, once you have your velocity node sorted, do you still need to use the chronograph?

After all the magnetospeed will cause headaches with group tests because as you have said, it will affect barrel harmonics. I haven't watched Eric's videos in a while so could be wrong.

why in hell would you still want to use it???? you have the powder charge settled upon....from that point onwards your velocity will be a given....or you wasted all rounds fired up till that point in time.....

Originally Posted by Rated M for Magnum

Just a suggestion, once you have your velocity node sorted, do you still need to use the chronograph?

After all the magnetospeed will cause headaches with group tests because as you have said, it will affect barrel harmonics. I haven't watched Eric's videos in a while so could be wrong.

Micky go sit in a corner with your dunce hat on
@Rated M for Magnum once you have your velocity node, likely you will then stat tutu'ing with the seating depth to find the sweet spot, this should definitely be done without the Magneto speed on as it "could" effect grouping and or group size. however once you settle on seating depth I would suggest it prudent to then whack the magnetospeed back on and shoot some rounds to verify velocity as changing the seating depth will change the velocity....or do a drop test and use that to verify your velocity the choice is yours

Originally Posted by Rated M for Magnum

Just a suggestion, once you have your velocity node sorted, do you still need to use the chronograph?

After all the magnetospeed will cause headaches with group tests because as you have said, it will affect barrel harmonics. I haven't watched Eric's videos in a while so could be wrong.

So the 1/3 moa groups my 223 HB shot with a magnetospeed on the muzzle were flukes?? If so then how about the 1/2 moa ones shot with a std weight Tikka?? Ive shot hundreds of groups with various magnetospeeds and never ever detected any change in group size. Like any device you attach to a rifles muzzle some rifles will show a change in point of impact . . . But thats another thing.

Originally Posted by dannyb

Micky go sit in a corner with your dunce hat on
@Rated M for Magnum once you have your velocity node, likely you will then stat tutu'ing with the seating depth to find the sweet spot, this should definitely be done without the Magneto speed on as it "could" effect grouping and or group size. however once you settle on seating depth I would suggest it prudent to then whack the magnetospeed back on and shoot some rounds to verify velocity as changing the seating depth will change the velocity....or do a drop test and use that to verify your velocity the choice is yours

That makes sense, magnetospeed off for group testing then a drop test at range for validation once you've picked the best grouping seating depth.