Quickload 300PRC help

[leclairk]

I’m new to using quickload but not new to this load. My chrono has a velocity of 2910 with these parameters and QL has me at 2808. I’ve verified this load out to 1 mile. Can anyone identify what I may have screwed up or need to adjust? I am shooting suppressed but that wouldn’t add 100fps.
24” Barrel
RL26
Berger 215g Hybrid Target
Measured ADG fired brass for H2O
COAL 3.676”

 

[Bmghunter]

Usually assuming all measurable input values from you are correct, example barrel length, seating depth, h20 capacity etc are all correct, then people adjust burning rate factor ba to get the correct velocity. Weighing factor also affects it slightly but its some voodoo value with no real way to determine what it should be.

 

[Dogtown]

^^ this…it takes some work if you want to fine tune QL to match your data. There’s just so many different variables that are defaulted to values that work well in most cases, but not all cases.

H2O case capacity is one that I’ve seen off a bit more than I would have expected and depending on how much it’s off, the results can shift quite a bit. Usually I’ll check H2O, then dial up/down Weighing Factor - not by much though. Then it’s tweaking Burn Rate and Specific Heat.

Be careful you’re not making broad adjustments to fit one load, especially when it comes to powder value adjustments. If you get powder values in one load looking to match well, double check those same values in a different load that uses the same powder. Tweaks to powder and cartridge values can be saved in the file so they aren’t lost in the session, but be aware that updating QL data (the frequent database updates that become available every year or so from Neconos) will nuke your custom data unless you save a copy of the data file.

Ultimately I think it’s best to treat QL as a virtual load testing tool that makes predictions for you in order to save time/money. Don’t rely on it to give you exacting information. Use it to get ballpark ideas about how a bullet/powder will perform.

 

[Schütze]

^^ this…it takes some work if you want to fine tune QL to match your data. There’s just so many different variables that are defaulted to values that work well in most cases, but not all cases.

H2O case capacity is one that I’ve seen off a bit more than I would have expected and depending on how much it’s off, the results can shift quite a bit. Usually I’ll check H2O, then dial up/down Weighing Factor - not by much though. Then it’s tweaking Burn Rate and Specific Heat.

Be careful you’re not making broad adjustments to fit one load, especially when it comes to powder value adjustments. If you get powder values in one load looking to match well, double check those same values in a different load that uses the same powder. Tweaks to powder and cartridge values can be saved in the file so they aren’t lost in the session, but be aware that updating QL data (the frequent database updates that become available every year or so from Neconos) will nuke your custom data unless you save a copy of the data file.

Ultimately I think it’s best to treat QL as a virtual load testing tool that makes predictions for you in order to save time/money. Don’t rely on it to give you exacting information. Use it to get ballpark ideas about how a bullet/powder will perform.

Is h20 case capacity measurement taken with your choosen bullet at your seating deep?

 

[Bmghunter]

Is h20 case capacity measurement taken with your choosen bullet at your seating deep?

No. It’s the full case capacity after fire forming filled to the top of the case mouth. Flat or overflow, there’s conflicting info on that.

 

[Dogtown]

Yeah, I just take a fired case with the primer still seated, weigh it, then pour some water/alcohol mix into the case until it reaches the top and re-weigh it - done. If you want to get OCD about it, repeat those steps with five different cases and average the result.

 

[leclairk]

^^ this…it takes some work if you want to fine tune QL to match your data. There’s just so many different variables that are defaulted to values that work well in most cases, but not all cases.

H2O case capacity is one that I’ve seen off a bit more than I would have expected and depending on how much it’s off, the results can shift quite a bit. Usually I’ll check H2O, then dial up/down Weighing Factor - not by much though. Then it’s tweaking Burn Rate and Specific Heat.

Be careful you’re not making broad adjustments to fit one load, especially when it comes to powder value adjustments. If you get powder values in one load looking to match well, double check those same values in a different load that uses the same powder. Tweaks to powder and cartridge values can be saved in the file so they aren’t lost in the session, but be aware that updating QL data (the frequent database updates that become available every year or so from Neconos) will nuke your custom data unless you save a copy of the data file.

Ultimately I think it’s best to treat QL as a virtual load testing tool that makes predictions for you in order to save time/money. Don’t rely on it to give you exacting information. Use it to get ballpark ideas about how a bullet/powder will perform.

Thanks for the info. I tweaked a little in all three categories to get me close enough. It’s a little frustrating/concerning that someone has to do that for it to be accurate. Had I not known my load already I would have probably started at 78 grains based on what QL told me and probably hit pressure pretty quickly. It is what it is. Clearly QL is just one of the tools needed when finding a load, but not the only tool.