04-18-2014, 01:48 AM
WildBill and others of yall who will be using an in-spec Grendel reamer on the throats of their barrels, I wonder if you could take the time to see what section of the throat begins cutting first, and then if all of the remaining throat needs some metal removed. I think that this could be done by sight, or by coloring the edges of the reamer with dychem or a sharpie. If someone us doing this by hand, the first area to make contact might be seen more clearly by turning the reamer backwards.
I have no reason for asking this other than my own curiosity, so if it is any trouble, please do not bother. In my mad scientist mode the other day, I thought up a number of reasons why any one or all of the surfaces might not meet spec. I just wonder if any of my ideas are right or whether I missed the boat completely.
While in that mad-scientist mode (also called insomnia), I ran some quick calculations from the SAAMI drawing. Then I did a rough scaling of the photo of the chamber casts (and when I say "rough", I'm not joking). According to the SAAMI drawing, on a barrel with a bore (lands) of 0.256" diameter and grooves of 0.264" dia, the rifling should become apparent fairly near the beginning of the 0.5 degree section (the beginning of the 0.5 degree section of the throat is only 0.2644" diameter). In other words, the rifling should show up in the first section of the throat.
Using my non-calibrated eyeball, the rifling breakthrough should be somewhere between where it appears on the two chamber casts. One of the problems is that I cannot tell if there is any 0.5 section of throat or if the 1.5 degree section starts at the right place or, for that matter, is if that section is really 1.5 degrees after all.
If the transition from the neck to the throat is short, this would be interesting to know.
Is this where I should do my Mad Scientist laugh? Mwwaaa hahaha!
Thanks,
Jim
I have no reason for asking this other than my own curiosity, so if it is any trouble, please do not bother. In my mad scientist mode the other day, I thought up a number of reasons why any one or all of the surfaces might not meet spec. I just wonder if any of my ideas are right or whether I missed the boat completely.
While in that mad-scientist mode (also called insomnia), I ran some quick calculations from the SAAMI drawing. Then I did a rough scaling of the photo of the chamber casts (and when I say "rough", I'm not joking). According to the SAAMI drawing, on a barrel with a bore (lands) of 0.256" diameter and grooves of 0.264" dia, the rifling should become apparent fairly near the beginning of the 0.5 degree section (the beginning of the 0.5 degree section of the throat is only 0.2644" diameter). In other words, the rifling should show up in the first section of the throat.
Using my non-calibrated eyeball, the rifling breakthrough should be somewhere between where it appears on the two chamber casts. One of the problems is that I cannot tell if there is any 0.5 section of throat or if the 1.5 degree section starts at the right place or, for that matter, is if that section is really 1.5 degrees after all.
If the transition from the neck to the throat is short, this would be interesting to know.
Is this where I should do my Mad Scientist laugh? Mwwaaa hahaha!
Thanks,
Jim