Quote:
Originally Posted by noshow
Very interesting thread, but I have found some contradicting data from Hodgdon's online data manual. Most folks here seem to agree that a slight bump in powder weight using 357 brass is beneficial, however Hodgdon appears to claim the opposite! I used their calculator and selected 148gr HBWC & HP-38 for both calibers, their results:
38 SPECIAL
3.5-4.0 grains, 869-956 fps
357 MAGNUM
3.0-3.4 grains, 845-908 fps
Note the MAX load for 357 is BELOW the 38 STARTING load ??????????
Very confusing to say the least! I think I've lost my faith in Hodgdon's calculator. Any thoughts?
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Besides what OKFC05 posted above, I can give you a most probable mechanical issue limiting the 357 Mag data with that bullet. What I think you are seeing with this data is due to the test setup they are using for both calibers. They are most probably using a closed chamber test barrel for testing both 38 Special and 357 Mag and most probably using the same test barrel to measure both. Since 38 Special cases are only physically different from 357 Magnum in length only, a 38 Special round shot out of a barrel that can chamber both cartridges would treat the 38 Special rounds as a closed chamber gun that has a very long leade or freebore and helps lower chamber pressures and possibly give a little more velocity, since the skirt will swell out to help seal the smooth bore section before the rifling.