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canuck4570
11-28-2005, 11:06 PM
when you have a mold maide by Mountain mold and you take it with the ogival flat point and a certain lenght of front driving band .... they give you the throat lenght ... I have a idea what that means but want to be shure before ordering... thank you for your time to answer me... Canuck.

The Nyack Kid
11-29-2005, 02:45 AM
canunk
the mountain molds online program is a rather simple program , it dosnt have a lot of options for calculating the throat . it runs a simple math formula to get the throat lenght. .it make some assumtions such as bore size and grove depth and leade angle . on the borerider nose , throat lenght is ,front band length +.015 inchs. for the cutter . simple trying to figger out how the program calculates the throat lenght for the ogival flat point has been an on going struggul (so has my spelling ) for me . if you click on "Rifle Throat Lenght" a "Explanation of Leade Length" pops up and reading it gives me headaches and flashbacks to college math classes .
changing the band diameter should change the throat lenght , it does if you make the diameter smaller , the program says you need a longer thoat, and that i am having trouble visionalizing

canuck4570
11-29-2005, 03:40 AM
thank you Nyack for the info.... I read the mountain molds section that explain the thraot lenght and as I understand it .... if the ogive tuches the begining of the rifling the bottom of the driving band should be inside the case just a bit or equal to the top...I think this his good ..well I hope this his for my 4570 and I have a mold from Jones mold... that has the front band .130 and when I make the front band tuch the rifling I have about .030 in the case so in the mountain mold graphic it says thraot lenght .146 so I should be about .046 inside the case... right.... I think hope desire to be right thank you fron canuck that has a ruger number one with a modified ramp to accept a burris scout scope.... just great.... and I had the balistic plex instald

The Nyack Kid
11-29-2005, 11:57 AM
I suppose that with a single shot you could seat the boolit deeper in to the case if the front drive band is too long and the boolit gets jammed into the rifling hard . with a levergun you are going to need a crimp grove and this is where the front drive band diameter and lenghts have to be worked with to get a better fit .the program will let you shorten the front driving band to shorten the throat . i had to have a smaller diameter front band to get the boolit to fit in my gun .