WCChapin | Round Nose Mauser – Hornady 170 RN and IMR 4166 in the Kar98k Sporter

Collecting 8×57 Mauser Hornady 170 RN / IMR 4166 velocity data for entry into Gordon’s Reloading Tool.

A few days back, 46.5 grains of IMR 4166 showed potential at 150 yards. I decided to chronograph a few charges in that area for evaluation. There seems to be a 2,600 fps plateau – it may be because the powder burnout occurs past the muzzle.

Based on the velocity data, the Optimum Barrel Time calculation in GRT predicts a node at 45.87 grains of 4166; behavior on target suggests that 46.7 grains may also be a region to explore. Autumn evening lighting and chromatograph accuracy/tolerance may be a consideration.

The parametric powder search in GRT (comparison with the 46.7 grain IMR 4166 charge) indicates that 47.0 grains of IMR 4064 would have a good barrel time, good case fill, and burnout just before muzzle passage.

My plan is to evaluate 45.8 – 45.9 grains of IMR 4166 (that covers the GRT node prediction) and the 47.0 grain region of IMR 4064 (to evaluate the parametric match based on the target).

I apologize for the attenuated audio at the bench – the video camera picked up conversation in the background that I felt was inappropriate for the video.

1940 337 Gustloff Werke Karabiner 98 k – sporterized
Ru Ruhrstahl AG barrel blank
Geco finished barrel
Weaver bases / Leupold Rifleman rings / Leupold M8-4X scope

8×57 Mauser – Canadian Dominion “7.92mm 44″ once fired surplus brass
Primer crimp removed, annealed and Neck sized with LEE Collet Die
Remington #9 1/2 Large Rifle Primer
Hornady #3235 8mm .323” 170 grain Round Nose
IMR 4166
Light crimp with LEE Factory Crimp Die

Gordon’s Reloading Tool https://www.grtools.de

Drone in D by Kevin MacLeod is licensed under a Creative Commons Attribution 4.0 license. https://creativecommons.org/licenses/by/4.0/

Source: http://incompetech.com/music/royalty-free/index.html?isrc=USUAN1200044

Artist: http://incompetech.com/

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