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Discussion Starter · #1 ·
Guys,

I am a newbie with QuickLoad ... mostly because am running it in a virtual machine on a Mac.

Have gotten very credible velocity and pressure predictions for 308 with AA2520 powder with several projectiles and barrel lengths. Also get credible results with 23.3 gr AA2200 in 5.56 with 55 gr Nosler BTs with barrel lengths of 11.5, 15, and 20".

When I do 6.8 Rem SPC with 28 gr AA2200 and 100 gr and 110 gr Accubonds at an OAL of 2.292 and twist of 12, the pressure prediction is clearly crazy (over 100k psi).

Something is obviously wrong. What are folks using for case capacity?

Thanks!

Mike
 

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I don't have quickload, but I have heard that it doesn't work for the 6.8---I'm sure others will post soon
 

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Guys,

I am a newbie with QuickLoad ... mostly because am running it in a virtual machine on a Mac.

Have gotten very credible velocity and pressure predictions for 308 with AA2520 powder with several projectiles and barrel lengths. Also get credible results with 23.3 gr AA2200 in 5.56 with 55 gr Nosler BTs with barrel lengths of 11.5, 15, and 20".

When I do 6.8 Rem SPC with 28 gr AA2200 and 100 gr and 110 gr Accubonds at an OAL of 2.292 and twist of 12, the pressure prediction is clearly crazy (over 100k psi).

Something is obviously wrong. What are folks using for case capacity?

Thanks!

Mike
We know that can't be right. Harrison has said many times that 28.5 2200 with the 110 Hornady is running at about 58k. QuickLoad is OK for helping get an idea what powders will work but you have to have all the numbers right, and even then it has exhibited some spectacular fails, much as you are seeing.

Its a modern day digital analogue to the old Powley Computer. That slide rule based tool was good for getting you in the ballpark, but not much farther. QuickLoad is only marginally better in my opinion.
 

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Guys,

I am a newbie with QuickLoad ... mostly because am running it in a virtual machine on a Mac.

Have gotten very credible velocity and pressure predictions for 308 with AA2520 powder with several projectiles and barrel lengths. Also get credible results with 23.3 gr AA2200 in 5.56 with 55 gr Nosler BTs with barrel lengths of 11.5, 15, and 20".

When I do 6.8 Rem SPC with 28 gr AA2200 and 100 gr and 110 gr Accubonds at an OAL of 2.292 and twist of 12, the pressure prediction is clearly crazy (over 100k psi).

Something is obviously wrong. What are folks using for case capacity?

Thanks!

Mike
I have QL vers. 3.5 and it does not work well with 6.8 loads. However, you can tweak it to get it close. I use case capacity of at least 36 usually higher. This is the place to tweak to get the predictions close to published load data.

I checked your loads, did some tweaking and got this:

powder: Accurate 2200
weight: 28.0 grains

my QL settings:
case length: 1.675"
cartridge length: 2.292"
max. case capacity: 37.500 grains
weighting factor: 0.5
shot start pressure: 3626 psi
barrel length: 16" (no twist rate function in my version of QL)

predictions:
100 gr. Nosler Accubond - 2574 fps - pressure=50,666 psi
110 gr. Nosler Accubond - 2562 fps - pressure=57,897 psi

That's not to far off what I would expect actual results to be for those 2 loads.
 

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Discussion Starter · #5 ·
Indeed the load is a safe one with the 110 gr Accubond. Was checking one I knew worked well.

My version of QuickLoad has a case volume of 34.0 gr of water. The 37.5 makes a HUGE difference in the results! Brings them right into line with what is rational.

Thank you!
 

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Guys,

I am a newbie with QuickLoad ... mostly because am running it in a virtual machine on a Mac.

Have gotten very credible velocity and pressure predictions for 308 with AA2520 powder with several projectiles and barrel lengths. Also get credible results with 23.3 gr AA2200 in 5.56 with 55 gr Nosler BTs with barrel lengths of 11.5, 15, and 20".

When I do 6.8 Rem SPC with 28 gr AA2200 and 100 gr and 110 gr Accubonds at an OAL of 2.292 and twist of 12, the pressure prediction is clearly crazy (over 100k psi).

Something is obviously wrong. What are folks using for case capacity?

Thanks!

Mike
I just plugged the data you mentioned for the 6.8 into my QL and it shows a pressure of 56860 psi...

That's near max according to QL, but not near the 100K you are getting...

Good-luck...BCB
 

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My version of QL has the bulk density wrong for AA2200. I measured how much the case can hold, level with the neck, and tweaked the numbers to get the capacity to match.

The velocity came out a little slow so I had to tweak the weighting factor down and then work the burn rate back up.

I think I need to pay for the latest update.
 
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