Primers
Posted: Fri Nov 11, 2016 10:59 am
Having used the Russian KVB-223 primers over the last year, and finding them a tad soft, I measured the cup thickness, together with the magnum version, BR4, and Rem7.5's.
I potted them in some resin and ground them down to make a crude microsection......see attached pic.
Measurements were made with eyepiece graticule calibrated with stage micrometer. (1.0mm into 100divisions), Nikon Labophot 2 microscope.
For what it's worth, here are the results:
A= Rem7.5 Thickness of cup where the firing pin hits it: 0.027"
B= KVB-223M : 0.024"
C= BR4 : 0.027"
D= KVB-223 : 0.019"
I wasn't too sure about the 223M's, but after measuring them, I tried them with a stiffish load (155 Scenar at 3075fps) in 308 Palma cases, and they were fine.
I also measured these: (Same technique ).
KVB-223 Std, (the copper coloured type Lot 1-11 that were available initially) : 0.020"
Federal 205 SR : 0.022"
Sellier & Bellot SP : 0.015"
Anyone who's used both the original copper plated std KVB's and the latest std brass coloured version will know that the later type are less robust, although the thickness is almost identical.....The copper plated version is probably a tad harder.
However, the KVB-223 Magnum's are in a different league altogether.............I've now found them to be very consistent, and hard enough to be a very good substitute for BR4's at almost 1/3rd of the price. Now my std. primer, and at £21-50/1000, a definite no-brainer.......get 'em from HPS-TR.
Pete
For some reason the layout has changed between the "preview" and my typed out version
I potted them in some resin and ground them down to make a crude microsection......see attached pic.
Measurements were made with eyepiece graticule calibrated with stage micrometer. (1.0mm into 100divisions), Nikon Labophot 2 microscope.
For what it's worth, here are the results:
A= Rem7.5 Thickness of cup where the firing pin hits it: 0.027"
B= KVB-223M : 0.024"
C= BR4 : 0.027"
D= KVB-223 : 0.019"
I wasn't too sure about the 223M's, but after measuring them, I tried them with a stiffish load (155 Scenar at 3075fps) in 308 Palma cases, and they were fine.
I also measured these: (Same technique ).
KVB-223 Std, (the copper coloured type Lot 1-11 that were available initially) : 0.020"
Federal 205 SR : 0.022"
Sellier & Bellot SP : 0.015"
Anyone who's used both the original copper plated std KVB's and the latest std brass coloured version will know that the later type are less robust, although the thickness is almost identical.....The copper plated version is probably a tad harder.
However, the KVB-223 Magnum's are in a different league altogether.............I've now found them to be very consistent, and hard enough to be a very good substitute for BR4's at almost 1/3rd of the price. Now my std. primer, and at £21-50/1000, a definite no-brainer.......get 'em from HPS-TR.
Pete
For some reason the layout has changed between the "preview" and my typed out version