6 mm dasher loads
- Thread starter maddysdad
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QuickLOAD, set for 68gr Berger, loaded to touch rifling, with .180 of bullet shank,bearing surface) in neck, with a 63,000 psi max load, predicts roughly 3700 fps with a number of powders including H322, BL-C2, H335, Win 748, Ramshot TAC, Accurate 2520.
I'd probably start with H322 because of its known excellent accuracy. Peak velocity is predicted with Win 748.
Keep in mind, this is only a prediction, but usually my QL sims come within 30 fps or so.
Same specs, loaded away from the lands, the projection is:
Load Density | Grains | FPS | psi |
Winchester 748:
99.1 38.2 3753 63000 Near Maximum !
Accurate No.2520:
101.0 38.6 3724 63000 Near Maximum !
Hodgdon BL-C2:
99.8 38.9 3720 63000 Near Maximum !
Hodgdon H335:
96.3 37.5 3708 63000 Near Maximum !
WARNING: This is only a computer projection. With all these powders I would start at 32.0 grains and work up. This also assumes an H20 capacity of 41.0 grains. You should measure the ACTUAL capacity of your fired cases. If it is less than 41.0 grains, that will dramatically increase pressure. For example, with 40.0gr H20 capacity, the pressure of 38.6gr of AA 2520 is 67341 psi,with bullet seated OUT of lands). That is high enough to damage brass and be dangerous.
Likewise, if your bullet is seated further down the neck that will increase pressure dramatically. When dealing with any new load, be conservative.
I'd probably start with H322 because of its known excellent accuracy. Peak velocity is predicted with Win 748.
Keep in mind, this is only a prediction, but usually my QL sims come within 30 fps or so.
Same specs, loaded away from the lands, the projection is:
Load Density | Grains | FPS | psi |
Winchester 748:
99.1 38.2 3753 63000 Near Maximum !
Accurate No.2520:
101.0 38.6 3724 63000 Near Maximum !
Hodgdon BL-C2:
99.8 38.9 3720 63000 Near Maximum !
Hodgdon H335:
96.3 37.5 3708 63000 Near Maximum !
WARNING: This is only a computer projection. With all these powders I would start at 32.0 grains and work up. This also assumes an H20 capacity of 41.0 grains. You should measure the ACTUAL capacity of your fired cases. If it is less than 41.0 grains, that will dramatically increase pressure. For example, with 40.0gr H20 capacity, the pressure of 38.6gr of AA 2520 is 67341 psi,with bullet seated OUT of lands). That is high enough to damage brass and be dangerous.
Likewise, if your bullet is seated further down the neck that will increase pressure dramatically. When dealing with any new load, be conservative.
WARNING: This is only a computer projection. With all these powders I would start at 32.0 grains and work up. This also assumes an H20 capacity of 41.0 grains. You should measure the ACTUAL capacity of your fired cases. If it is less than 41.0 grains, that will dramatically increase pressure. For example, with 40.0gr H20 capacity, the pressure of 38.6gr of AA 2520 is 67341 psi,with bullet seated OUT of lands). That is high enough to damage brass and be dangerous.
Likewise, if your bullet is seated further down the neck that will increase pressure dramatically. When dealing with any new load, be conservative.
Take a fireformed Dasher, load with a stiff charge,32gr Data 74 naked Hornady 105 A-Max)then measured with a 70 gr Sierra BlitzKing pushed into the case to the point[and displacing the water] where the bullet would be seated,.120 neck bite) yeilds a max of 39.6 gr of H2O. You either have a bigger Dasher or heavier water.
Mark
Likewise, if your bullet is seated further down the neck that will increase pressure dramatically. When dealing with any new load, be conservative.
Take a fireformed Dasher, load with a stiff charge,32gr Data 74 naked Hornady 105 A-Max)then measured with a 70 gr Sierra BlitzKing pushed into the case to the point[and displacing the water] where the bullet would be seated,.120 neck bite) yeilds a max of 39.6 gr of H2O. You either have a bigger Dasher or heavier water.
Mark
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Varminator,
For QuickLOAD purposes, the case capacity value is without a bullet seated, measured to the top of the neck. It may indeed be less than 41.0 grains, but it's not necessary to seat a bullet. The program handles the reduced case capacity,from putting a bullet in the neck) automatically, using the bullet data in its files, combined with the OAL as imput by the user.
For QuickLOAD purposes, the case capacity value is without a bullet seated, measured to the top of the neck. It may indeed be less than 41.0 grains, but it's not necessary to seat a bullet. The program handles the reduced case capacity,from putting a bullet in the neck) automatically, using the bullet data in its files, combined with the OAL as imput by the user.
My scale is right on with check weights using water to the neck without surfactants I still get less than 40 actual grains of water.
Mark
Mark
My Dasher Lapua cases run 41.6 grains H2O. +0 headspace chamber, no trimming at all. I am confident of this number as I measured a bunch, and averaged.
Cheers,
Cheers,
Moderator stated: For QuickLOAD purposes, the case capacity value is without a bullet seated, measured to the <top of the neck. >It may indeed be less than 41.0 grains, but it's not necessary to seat a bullet. The program handles the reduced case capacity,from putting a bullet in the neck) automatically, using the bullet data in its files, combined with the OAL as imput by the user.
Sorry, senior moment there like a stuck record, to the top of the neck as in, fill the whole case. I get it. 41.8 gr.
I sincerely apologize for the confusion.
Mark
Sorry, senior moment there like a stuck record, to the top of the neck as in, fill the whole case. I get it. 41.8 gr.
I sincerely apologize for the confusion.
Mark
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