Thread: Frustrating arvo at the range. Powder charges.

Originally Posted by Snowgrass

Good observations, I hadn’t looked at the pan mounting. If I got really enthusiastic I could screw the brass screw the weight is on out a fraction but I’m sure it’s got locktight from a quick test so don’t want to damage anything for no real gain. I’ll get hold of some check weights which should negate any deviations on the beam balance weight by checking each time it’s moved.

Adjustment of the screw to align the 10 will misalign the zero. If you could adjust it you would be looking for a happy medium where it’s out a bit at both ends and not noticeable (it would be out by the amount it’s out at the 5 grain mark, but it would be by this much at zero and ten and aligned at .5
As I said the only fix is to adjust the thread pitch (impossible to do properly).
The one other option is to peel off the sticker with the 10-0 measurement, photocopy it and scale it up by a cats whisker so that the drum aligns. Not that you would want to bother.

Originally Posted by gqhoon

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.

Where does Erik suggest this? I've just had a quick skim through some videos but couldn't find this.
Looking for MV flat spots when your ES is ~80 FPS is a waste of time. In my experience most "flat spots" are a product of load variance and measurement error and aren't typically repeatable.
Looking for vertical on target (and choosing a charge that has low vertical variance compared to charges either side) makes sense, to understand what the barrel harmonic is doing.

Originally Posted by Tentman

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.

Not saying they were flukes, nor would I say that about anyone's groups

I do not own a magnetospeed but have seen feedback from people who have used them saying that the point of impact can change with it fitted vs it being off and the potential for it to alter barrel harmonics. The reason I suggested the removal when testing group size was to eliminate this potential variable. Also so that only group size is being measured as the velocity had already been established.

That is very interesting that it has not altered group sizes in your tests, thank you for sharing your experience

Originally Posted by chalkeye

Where does Erik suggest this? I've just had a quick skim through some videos but couldn't find this.
Looking for MV flat spots when your ES is ~80 FPS is a waste of time. In my experience most "flat spots" are a product of load variance and measurement error and aren't typically repeatable.
Looking for vertical on target (and choosing a charge that has low vertical variance compared to charges either side) makes sense, to understand what the barrel harmonic is doing.

It is literally the basis of his load development process. From his website, copied and paste below:

Load Tuning:

Powder charge/Primer testing:

1. Select 2-3 primers to test

2. Select powder to test (one powder only)

3. Find safe starting load for powder in your rifle

4. Find jam and seat bullet Jam -0.020” or shorter depending on your needs

5. Load 10 rounds of each powder/primer combo in 1% increments (about 0.2 gr)

6. Shoot them from low to high and stop if you see pressure signs.

a. Flattened primers

b. Gas leakage around primer

c. Heave bolt lift

d. Etc.

7. Graph the speed results and find flat spots on speed. Select the one that suits your needs best.

8. Load rounds to middle of flat spot and do seating depth test in 0.003” increments seating deeper into case with each group. Find the load that shoots the best.

9. Tuner testing: If you have a tuner, you can skip step #8 and move straight to tuner testing. Find a settings that give you two consecutive small groups and set tuner to middle of those settings.

10. Once you are done with seating depth test, load the best seating depth test and load your target powder charge and also load .2, .4, and .6 gr. above and below your current powder charge and test. Shoot groups from low to high, if you encounter pressure signs, stop.

11. You should now have a very stable load. If your load has low ES/SD and shoots small groups at 100 yards, then it will shoot at long range. If it doesn’t shoot at long range, then you need to sort your bullets. Easiest way to sort them is base to tip. Other ways is to sort base to ogive.

12. Buy quality bullets: Start with Berger bullets, which are proven to shoot well. Once you get Berger bullets shooting well, you can experiment with other bullets if you wish.

13. The same goes for good brass. Start with Lapua if you can, as it is proven to be very consistent brass.

A couple of times ive faffed all day making .75s down to .25s and then got down to my pulled 'bent' barrel warmers and then shot a pinhole group. It does your head in tbh. Some of that is random luck but some is just being relaxed and not placing pressure on yourself.

Thanks. That must be from the membership content area? I still can't find it anywhere online.

Regardless, I stand by my point that most people aren't controlling MV tight enough to gather meaningful "flat spot" insights. Erik might be an exception but I've not seen the data.