? for QuickLoad Guru's

[Trikstr]

I'm trying to get the predicted velocities to match up with what I'm seeing.
All the variables that I can measure have been accounted for except for my barrel being faster(maybe) than predicted.
Can I adjust the Ba(burning rate factor) to try and get velocities to what I'm seeing and also watch chamber pressure predictions to try and stay out of trouble?
Hopefully that's clearer than mud.
Thanks

 

[FOTIS]

I would not do it.
Remember it is only a reference just like a manual. Your mileage will almost always vary!

 

[DrMike]

I'm with Fotis on this. Burn rate is determined in a calorimeter bomb. Unless you have this equipment and the capacity to derive numbers from it, you're playing with fire (literally).

 

[OU812]

You will do well to listen to these guys advice.

Bill

 

[Trikstr]

Running a test spread with bullets seated progressively deeper. Looking for accuracy. Got too windy to move on to second batch. Velocity this AM through 35P ran 120 fps faster than QuickLoad predicted. I guess that's the trouble with predictions. I've seen this with several other cartridges.
Playing with Ba to get vel. to match increases press.. Wanting to stay out of trouble!
Thanks

 

[joelkdouglas]

Trikstr,

1. Listen to reason from Dr. Mike and FOTIS. They have several more years experience with Quickload and hand loading than I, with only 3 weeks time with Quickload and 3 years hand loading.

2. I've changed the Ba of one powder to match what I'm seeing for velocities with several bullets, but only with Ramshot Hunter thus far. There are several things I would do before I considered changing the Ba--first, have you weighed water in your cases with fired primer or somehow sealed the primer hole? The actual case capacity makes a big difference.

150 fps is not too far off the mark, I think. Supposedly powder lots can vary as much as 10% off the tested data, but I wouldn't change Ba based on that. Assuming your velocity is 3000 fps, 150 fps is 5%, if the public math I just did in my head is correct.

Measure all your bullets! Measure OAL of bullet, bearing surface, etc. Correct these figures in Quickload, as most all the bullets are a bit off.

Quickload also predicts velocities at higher temperatures, but this feature is very rudimentary, as found out by me this weekend. If possible, shoot a "ladder" of varying loads at a set OAL with at least 2 Nosler bullets for velocity data. Shoot this as close to 70 degrees as you can, to match Quickload's prediction. If you've only shot one load, or one bullet, that's not enough data. For example, Accubonds normally run about 50 fps faster out of my rifle than Partitions.

Also, I would hesitate to change Ba without some pressure estimation. Ramshot happens to print pressures in PSI in their loading data, so I feel comfortable matching up my chrono velocities with Ramshot's pressure data with Ba. I just so happens that all these numbers lined up for me when I modified Hunter.

Also, Quickload will not allow you to permanently change the powder data. You can save a new file, or hand jam every time, but you can't mess up the powder data, so don't worry about that.

I have read not to change Ba more than 5% from Quickload's data. If your velocities are still incorrect, play with bullet weight a grain or two. Then weighting factor up to 0.05.

3. Know that when you change the Ba of your powder, you still need to be within a load manual's safe limits. When I changed Ba of Hunter I actually loaded down in powder amount. I would not ever load up based on changing Ba, and never above Nosler's (my preferred) max load. I believe Nosler's manual to be more accurate based on the fact it's more conservative than others.

4. Know that when you change the Ba of your powder, your model is wrong. It was wrong to begin with, and now it's still wrong. Don't make any decisions based on Quickload--you have to use what God gave you first.

5. See #1, above.

v/r
Joel

 

[joelkdouglas]

I've also been using this formula for starting pressure, found at Reloader's Nest. I don't know that it's correct, although I also cannot prove otherwise.

((bearing length, in inches) x 1420) + 2860 = starting pressure.

The 180 Nosler Partition, for example, has a bearing length of 0.639 inches.

0.639 x 1420 = 907.38 + 2860 = 3767.38

Add another 600 if using magnum primers, so 4367 for the Partition.

I believe those numbers represent staring pressure in psi.

Any updates on velocities? After you calibrate Quickload are your numbers closer?

 

[joelkdouglas]

I've seen this with several other cartridges.

After reading this portion of the statement again I believe there are some internal to QL calibrations you should do before modifying Ba.

What powders are you using?

 

[RiverRider]

In my opinion, the burn rate (Ba) should only be changed if it can be demonstrated that the particular lot of powder in question produces velocities that differ from QL's predictions in several different cartridges, and in some kind of a consistent manner. Otherwise you may be diddling a number for burn rate when in reality the difference between predicted and actual velocities is due to some other factor. Could make trouble somewhere along the way.

 

[Trikstr]

Some more info from NECO(where I got my copy) and also the owners manual, bottom of page 66 and top of 67(my copy).
I was playing with the Propellant window-Interactive mode and you most can deffinately make permanent changes in the selected powders burn rate. Called distributor(NECO) and he walked me through restoring it to original spec.. He also told me that you can make changes to the Burning rate factor to make chrono data match up better to quickload predictions, but not to change more than +/- 10%. This is also covered on page 66/67.
Hope this helps fellow QL users.