I am a new user of QuickLOAD struggling up the steep slope of the learning curve. Here is what I think is the right approach to tuning QL to predict the right charge weight for an Optimal Barrel Time accurate load. Will you experienced QL users please critique.

I am aware of adjusting the Burning Rate Factor (Ba) to calibrate QL. Please tell me if there are others that should be used in additions to or instead of.

Here is my method:
1. Pick a bullet and powder you want to develop an OBT load for.
2. Load 5 rounds with the starting load from the manual of the manufacturer of the bullet you are using and fire them over your chronograph and average the actual measured velocity.
3 In QL enter the actual measured dimensions of your components:
Barrel length from bolt face to muzzle.
Bullet brand, weight, length, and diameter.
Cartridge length and volume capacity in grains of water.
Powder and charge weight.
Actual measured velocity.
Apply and Calculate.

The predicted velocity will not agree with your actual measured velocity so you make adjustments to the Ba until the predicted velocity and the actual measured velocity match.

Then you adjust charge weight until the barrel time matches an OBT node. This charge weight should be a starting place from which to fine tune charge weight variances in 0.1grains increments as well as seating depth, etc.

Are there other things I should do other than this?

That's a good summary.
However, I find loading to near max pressures/ velocity as predicted by QL, then varying seating depth until you get accuracy, more successful than trying the obt technique.

Do you do that after you have calibrated QL with a known measured velocity, or do you do that instead?

Yes caibrate to ql and then load at the velocity you want, trying diff seating depths.

OK, thanks Dead Eye. Do you adjust anything other than Ba to calibrate QL?

2/22/08 – Author: Chris Long, AKA TechShooter

Adjusting the Powder Burn rate Factor and the Bullet Weight to Help Match
QL to Range Chronograph Data:

Getting QL to match your actual, range measured load performance s the very best
way to ensure that you have reached the OBT desired. Once the QL simulation results
in terms of predicted muzzle velocity track range data over a reasonable range of
power charge weights, you can then set QL to calculate that actual charge weight that
will produce an OBT load.
There are two primary methods of adjusting QL to achieve this goal: Modifying the
power burn rate factor, and slightly adjusting the bullet weight.

https://www.google.com/search?...0i30k1.0.vL_pNWsgalQ

Yes I change the ba to match the velocity.
Others swear by the obt method but it hasn't worked that well for me.
Often I'm between "nodes" where moving down lacks cartridge performance and up is over pressure

quote:

Reply

Don't forget to adjust your weight factor for the cartridge your using and adjust your start pressure.. QL uses 3625 as a start pressure, but add 7200 psi to this # for 10825 psi when the bullet is jamed to the lands then substract 145 psi for every .005 you are from the lands. I find this works good. The weight factor should be adjusted before you adjust your burn rate (BA) to match the vel you get. This works for me.

That's all fine and good and your keeping good records, I do this as well..but lets get to the point of what your doing and that is to find a true max load for your rifle..Most advise is given based on book loads that in most cases are rather mild loads..

I look for signs of pressure and when they show up. I start at less than book max by a grain or two...What I expect is it too reach pretty close to book max at book max easily, then cut to 1/2 gr. increses, first I usually get flat primers ( not much meaning to this but it time to get serious) primers vary in strength of metal..Next I many get a flat primer and and an extractor mark, a black ring around the primer, a sticky bolt, a crack as opposed to a boom; all which tells me its time to mic the cases for expansion, I like zero expansion but .0005 is max in most any rifle. I chronograph the load ( use a single case starting with a new one) with every firing, reload that case each time, the resizing die tells the story with loose primers..when I get a combination of two, in rare cases three of the above pressure signs with a shot and reload, I cut back two grains and work on accuracy, but still paying attention to the case, velocity and reloading of that single case..and with new brass..

I may modify the order of the above in some cases if I see something going on that bothers me. I suppose its important that I confess that I have been doing this for more years than I can remember, so if one is a newbie to the game I would suggest you walk on egg shells, your flying by the seat of your pants without a parachute..

Its a learning process..The worst Ive done is a couple of blown primers that ruined the case, a couple of sticky bolts, one I hammered open but it wasn't all that stuck and worst of all I blew the extractor off a Win mod 70 but that was with a book load that turned out to be a misprint by Harvey as I recall...Never close to blowing a gun up..