Author Topic: leading in a 9mm Browning HI Power  (Read 773 times)

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Offline 38-44

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leading in a 9mm Browning HI Power
« on: November 08, 2010, 08:44:20 AM »
Hi Veral
I own a prewar Browning HP in mint condition and I have some trouble to make it decently shooting.
First there is no play and the barrel mikes .357; 6 grooves ;1 in 10" pitch, mirror shining and no constriction after slugging.
I have tried Lyman 356402 and 358242 calibrated at .3575 from 15 to 22 BHN
With powders Vectan Ba9 (~Unique) Ba10(~Beye) A0, A1, As, Sp2 ( B dot) .  with VV N320,330,340,3N37. from starting loads to near max
bullets lubricated with NRA 50/50 or LBT Blue soft
bullets seated 1/16" off the lands
Velocities ran from 850 to 1250 fps.
The best 10 shots from a rest are over 5 inches at 25 yards. There is no keyholing
and all but the lightest loads lead badly and need Lewis LR each 5 shots
Do you think one of your molds could do better or is there anything I have missed?
Thanks for your answer
38-44

Offline Veral

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Re: leading in a 9mm Browning HI Power
« Reply #1 on: November 09, 2010, 04:53:29 PM »
  In my opinion there are no other molds which can match performance of my molds, nor can other designs match mine.  I have thousands of customers who have the same opinion, and if I didn't have those custmers I wouldn't have this opinion!

  However I don't believe design alone is your problem in this case, because your discription of the problem indicates the leading is occuring only with light loads, which is a common problem when bullet diameter is less than groove diameter.  As power level gets high enough to obturate the bullet bases, the gas blowby is sealed off and the leading problem stops.  If this is your problem, sizing  to a little over groove diameter should fix the problem.  Also, seating to lightly contact the throat may help or completely fix the problem, as contact with the throat, if bullets are at groove diameter, forms a gas seal.
Veral Smith