Quick Load advice

[Retired2021]

I just started using Quick Load and tuning loads with OBT (I assume that means optimal barrel time?) to tune loads. I have two rifles that it seems to have worked very well in load development. I have a couple of questions for the LRH community.

Question 1: What do you think of using Quick Load to tune using OBT?

Question 2: I am loading for a 223 Rem using H335. After tuning Quick Load to the water weight and H335 to my measured velocity, Quick Load indicated I could go up a full 2.9 grains OVER the max load listed in the Hornady book. Using Hornady 55 SP the book indicates a max of H335 of 23.2. Quick Load tuned to my rifle indicated that 26.1 would be safe. With great caution I tested the load (sandbags to hold the rifle and pulled the trigger with a rope from 15 feet). The loads did not show any sign of pressure and velocity was within 5 fps of that predicted by Quick Load. I have heard that each lot of powder is different and when using a different lot number to drop back and work up again. Before I trust Quick Load on this kind of thing I want to know if others have had similar experience. Do you trust Quick Load, when tuned to your powder and rifle, to predict loads that are over book maximum? I didn't mind the test because the rifle in the test was low end, but if I am getting on thin ice, I don't want to do this (exceed book max when QL indicates it is still safe) with a rifle I paid a lot for.

 

[lancetkenyon]

Did you jump right from 23.2 to 26.1? Or did you creep up in approximately 1-2% increments? Like 23.5, 23.8, 24.1, 24.4, etc? Hodgdon shows 23.0 starting amd 25.3 max. A 10% increase.

Jumping up 12% in one step for charge weight is crazy. You should definitely not do that again if you did.

 

[Mikecr]

It sounds like you have QL well calibrated.
I do not buy into OBT as useful.

 

[Willys]

Once QL is calibrated to that lot of powder yes I expect my results to match it fairly close. NO I would not jump to a max or over max load based on what QL says. ALWAYS work your way up 1%-2% at a time. Rope and trigger ? Noooooo!

 

[abstewart66]

I use both QL and OBT as well as the OCW 3% rule. QL is as good as the inputs, but certain powders (N140, IMR3031) require adjusting Ba (sometimes quite a bit) to true the velocity. I also look closely at whether or not Pmax and Z1 are close. I have found that for most of my best loads, Pmax and Z1 are very close if not identical. Many times QL and OBT chart nodes are very close, although I will say that there are accuracy nodes that are in between the nodes on the OBT chart. So, once I find a node, I then use the 3% rule to find the next node area to test. I will say that lower charges seem to require larger Ba adjustments in order to true them based upon velocity. As one would imagine, burn rate seems to change with load density. That is what I do and it generally works. It really helps me minimize waste of components. That being said I would never make a large jump in powder charge simply based upon what QL tells me as it is nothing more than a predictive modeling program and it is more accurate with some powders and charges than with others. I hope that helps..

 

[Retired2021]

abstewart66, that was very helpful, thank you. Also thank you to the other replies. I wish I had started with purchasing QL a year ago. It would have saved me a lot of money purchasing powder and wasted components.

I am still not sure about OBT. It worked very well on two rifles, then not so well on three more. I will look into the relationship of Pmax and Z1 on the loads that did not group well.

I have hunted for almost 60 years and have been successful, but this precision shooting is a whole different game.

 

[Mikecr]

I believe that people want OBT to work so badly (because then it would represent a shortcut), that they put a lot of effort into convincing themselves that it does work (even where it clearly does not).
It is misnomer'd to begin in that OBT theoretically shows timing you DO NOT want a bullet to exit with. That is, when a vibration is at the muzzle.
Given this, it should be called detrimental barrel timing (DBT).
In no way does it imply where a bullet SHOULD exit between the points it should not. Only a target result can tell you that.

So between all the vibration points traveling back and forth, and where a target result tells you that you're in a barrel node, you can always find that you're 'close' to one of them vibration points. This seems enough to convince people who desperately want OBT to work -that it does.
But you can play with loads in QL, while you hold actual target results in hand, and see that OBT is utterly useless for prediction.

Vibrations of every sort and source sum in contribution to a barrel node. You cannot just hang a hat on a single vibration to represent a sum of them. You will always have to shoot for result.

 

[abstewart66]

abstewart66, that was very helpful, thank you. Also thank you to the other replies. I wish I had started with purchasing QL a year ago. It would have saved me a lot of money purchasing powder and wasted components.

I am still not sure about OBT. It worked very well on two rifles, then not so well on three more. I will look into the relationship of Pmax and Z1 on the loads that did not group well.

I have hunted for almost 60 years and have been successful, but this precision shooting is a whole different game.

Keep in mind that pmax and z1 are not always exactly the same for a great load, but in my experience, good loads typically have these 2 indicators relatively close together. Also, when using OBT, I read somewhere that barrel length tolerances can be within a half inch, so a 24" bbl can actually be anywhere from 23.5-24.5, and if you are using the OBT chart, my experience is that, for instance if looking at the 1.228 node, the QL barrel time number might be 1.19 or 1.29 for a good load, so you can't be too anal or you risk getting frustrated. And, keep in mind that some powder-bullet combos lend themselves to larger accuracy node windows than others. Thats my experience so far, and I hope it helps you as you progress in this hobby, which, in my opinion is loads of fun and a never-ending learning experience.

 

[mtJim]

I have used it successfully for five different rifles. I shoot a ladder over the magnetospeed, 10-15 shots in increments of case capacity - 30 some grains powder is .3 grain increment, 40 some is .4. Then start tweaking the QL variables to get the QL velocities to match the magnetospeed across the ladder. First make sure all of the QL inputs are correct - cartridge length, barrel length, water capacity. Then tweak powder Ba, shot start pressure, and weighting factor to get QL predicted velocities to (closely) match measured for each charge weight, this is some trial and error and sometimes takes a little effort. And need to closely match entire shot string, not just a small subset of it. I've found that once the predicted velocities are in line with my measured velocities, the QL pressures also align with pressure signs observed while shooting. If my ladder didn't go high enough to reach an observed max pressure, the QL estimate is a useful number, of course keeping in mind this is an estimate and slowly approach from a conservatively lower starting point. From here I find the OBT charge in QL then do an OCW test ranging from a little below the QL OBT charge to a little above. In all of my experiences QL OBT has been within .5 grains. I verified the first couple with a wider OCW test and landed in the same spot. Has been useful for a couple of wildcats where data is scarce. Also, load development is complete in 25-30 shots typically.

 

[Retired2021]

mtJim. Thank you for sharing your experience. It seems to me that a lot of folks don't like QL. I wonder if it is because they don't take the time to tune QL to their rifle and powder. My experience so far has been very positive using QL, except for one rifle, a Rugar Compact in 223, referenced above. I expect I will find it is not working well because of something I overlooked.