Bearing Surface Comparators
FULL Article with Photos Here:
http://www.6mmbr.com/medlerTubbBSC.html
I just recently received my Bearing Surface Comparator,BSC) from Superior Shooting Systems,SSS) or David Tubb. The BSC is a pretty slick setup. It is easy to use and quick. Prior to acquiring the BSC is used a Neil Jones 22 Rimfire gauge I modified myself for centerfire caliber bullets.
The table below shows my sorting results for some 77 grain 22 caliber and 175 grain 30 caliber Sierra MatchKing bullets.
DO READ the FULL BSC TEST linked above. It has updated info and lots of pictures that show the process.
The 175 & 77 Gr. bullets in the table below were not presorted using the Neal Jones gauge and both are the remaining portion of a 500 count box of bullets. After playing around for a while I decided to use the shortest bearing surface length as the base measurement and relate all others as plus to the base measurement in one thousand increments.
Relative Bearing----------175 Gr.-----77 Gr.-----80 Gr.
Surface length------------30 Cal.-----22 Cal.----22 Cal.
Shortest = Base Length-----3-----------3---------40
Base Length plus 0.001----15----------12--------132
Base Length plus 0.002----29-----------0---------74
Base Length plus 0.003-----1-----------0---------80
Base Length plus 0.004----11-----------2----------2
Base Length plus 0.005----38----------15----------0
Base Length plus 0.006----92---------207---------16
Base Length plus 0.007----17----------27----------0
Total------------------------206---------266--------344
If you look at the first two samples in the table above, it shows two distinct groups. The two samples above also show a predominate group which has a slightly longer bullet surface bearing length and separate smaller group with shorter bearing length. The third column is 80 grain bullets that were presorted using the Neal Jones gauge. So my initial results of sorting with either the Neal Jones gauge or the more accurate BSC both yielded similar results showing of two distinct bearing surface lengths in each box of bullets.
My bottom line for the BSC is that it is easy to use and gives very repeatable results. I found the BSC is about five times faster to use than my modified Neal Jones gage and the Neal Jones gage is twice as fast as trying to use a vernier caliper with couple of insert devices attached. So far I am very happy with my BSC.
Here is a link to David Tubbs BSC.
http://www.davidtubb.com/tcom_images/reloading/bsc_one.html
Here is a link to my Blog with more articles and BS.
http://mywebpages.comcast.net/jesse99/index.html#Reloading
FULL Article with Photos Here:
http://www.6mmbr.com/medlerTubbBSC.html
I just recently received my Bearing Surface Comparator,BSC) from Superior Shooting Systems,SSS) or David Tubb. The BSC is a pretty slick setup. It is easy to use and quick. Prior to acquiring the BSC is used a Neil Jones 22 Rimfire gauge I modified myself for centerfire caliber bullets.
The table below shows my sorting results for some 77 grain 22 caliber and 175 grain 30 caliber Sierra MatchKing bullets.
DO READ the FULL BSC TEST linked above. It has updated info and lots of pictures that show the process.
The 175 & 77 Gr. bullets in the table below were not presorted using the Neal Jones gauge and both are the remaining portion of a 500 count box of bullets. After playing around for a while I decided to use the shortest bearing surface length as the base measurement and relate all others as plus to the base measurement in one thousand increments.
Relative Bearing----------175 Gr.-----77 Gr.-----80 Gr.
Surface length------------30 Cal.-----22 Cal.----22 Cal.
Shortest = Base Length-----3-----------3---------40
Base Length plus 0.001----15----------12--------132
Base Length plus 0.002----29-----------0---------74
Base Length plus 0.003-----1-----------0---------80
Base Length plus 0.004----11-----------2----------2
Base Length plus 0.005----38----------15----------0
Base Length plus 0.006----92---------207---------16
Base Length plus 0.007----17----------27----------0
Total------------------------206---------266--------344
If you look at the first two samples in the table above, it shows two distinct groups. The two samples above also show a predominate group which has a slightly longer bullet surface bearing length and separate smaller group with shorter bearing length. The third column is 80 grain bullets that were presorted using the Neal Jones gauge. So my initial results of sorting with either the Neal Jones gauge or the more accurate BSC both yielded similar results showing of two distinct bearing surface lengths in each box of bullets.
My bottom line for the BSC is that it is easy to use and gives very repeatable results. I found the BSC is about five times faster to use than my modified Neal Jones gage and the Neal Jones gage is twice as fast as trying to use a vernier caliper with couple of insert devices attached. So far I am very happy with my BSC.
Here is a link to David Tubbs BSC.
http://www.davidtubb.com/tcom_images/reloading/bsc_one.html
Here is a link to my Blog with more articles and BS.
http://mywebpages.comcast.net/jesse99/index.html#Reloading
