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Discussion Starter #1
Looking at the following two loads, I'm confused...

260JFP  HS7  17.0  1228  36,000    24.0   1701  51,700
300JFP  HS7  16.0  1111  33,400    22.0   1501  50,200

I don't understand why the mim/max load for a 300gr show less pressure than for the 260gr.  I would think pressure would be greater the heavier the bullet because it would take longer to get the bullet started out of the case.  I got this data  from FA's web site. Can anyone help me out on this one? Thanks in advance.

God bless,
 

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Southpaw,

Three questions come to mind:<ul>
<li> Did the data specify primer selection?  A change in primers can make quite a difference in pressure.
<li> Did the data specify make of bullet?  It is possible that the 300 grain bullet has less bearing surface than the 260 grain depending upon style and manufacturer, thus reducing the friction coefficient of the heavier bullet.
<li> Did the data specify C.O.L.?  Depending upon the design of the bullet, the 300 grain bullet may have had a longer Nose to Crimp length, and actually taken up less space in the case than the 260 grain pill, thus lowering the pressure by increasing combustion chamber space.</ul>

These questions and the data pertaining to them all influence pressure/velocity results in any handload, more prominintly in handgun cases.  This is one of my pet peeves when it comes to published load data in some of the more prominent and better distributed gun magazines;  they publish loading data for a given cartridge, but invariably they omit C.O.L. and often times omit bullet manufacturer, so consequently someone applies the data printed, and gets MUCH different results, sometimes with dangerous pressures with the wrong combinations!

Let us know what you find out!

Always double check data with at least one other credible source if all pertinent aspects of the load aren't presented, and even then make sure that you error on the safe side of lower pressure/velocity to start!

God Bless,

Marshall
 

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Discussion Starter #3
Marshall, thanks for responding.  The was loading recommendations before the load data, but nothing to signify what was used in particular.  It just states that:
"LOADING RECOMMENDATIONS
FOR REVOLVERS MANUFACURED BY FREEDOM ARMS CHAMBERED FOR 454 CASULL ONLY!
ALL VELOCITIES ARE FOR : 7.5”  PRESSURE BARREL.~
BULLET DIAMETERS  ARE :.451 / .452
PRIMER SIZE :SMALL RIFLE  REM.  # 7 ½      
CASE TRIM LENGTH :1.380
MAXIMUM CASE LENGTH :1.385
MAXIMUM  O.A.L. LENGTH: 1.765".

God bless,
 

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Because it takes too much time do publish load data with increments of a 1/10th of a grain. They could ahve easily jacked it up a little as stayed safe.

But understand, it is you job as a reloader to determine safe loads and work up load data. It is very possible thay your gun could be pumping out  10K more psi given differing  tolerances of the 454 makers now around.

You really shouldn't worry about 1k differences since your gun will have more deviation than that.

-CAL
 
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