I spent better part of yesterday on the range testing loads for the 6.5x55 and 8x57. I said earlier in a couple of posts that I would post data, so here it is. All loads were 3-shot groups from solid rest with light cloth padding at 100 yards. Wind was light (non-factor). Minimum hree minute intervals between shots.
Data for 8x57 Mauser handloads with IMR 4064
Test rifle: sporterized K98 with 24 barrel; 4x scope.
150 grain Sierra SP
Charge (grains) Estimated velocity (fps) Group max. diameter (in) Group mean distance (in)
40.0 2150 2.5 1.33
41.0 2210 1.75 1.04
42.0 2270 2.75 >2
43.0 2330 1.75 0.86
44.0 2390 3.75 >2
45.0 2450 2.0 1.16
185 grain Remington core-lokt PSP
Charge (grains) Estimated velocity (fps) Group max. diameter (in) Group mean distance (in)
38.0 2050 3.5 >2
39.0 2107 2.5 1.38
40.0 2163 2.25 1.66
41.0 2219 1.75 1.25
42.0 2276 3.0 >2
43.0 2332 3.75 >2
44.0 2388 4.25 >2
45.0 2445 2.0 1.54
46.0 2501 5.5 >2
Data for 6.5x55 Swedish mauser handloads with IMR 4064
Test rifle: Kimber sporterized M96 with 22 barrel
85 grain Sierra HP
Charge (grains) Est. velocity (fps) Group max. diameter (in) Group mean distance (in)
42.5 2823 1.5 0.92
43.0 2869 1.75 0.92
43.5 2914 1.5 0.88
44.0 2960 1.5 0.83
44.5 3005 ? ?
100 grain Hornady Spirepoint
Charge (grains) Est. velocity (fps) Group max. diameter (in) Group mean distance (in)
39.0 2575 2.5 >2
39.5 2614 2.25 1.63
40.0 2652 2.0 2.0
40.5 2691 1.75 1.04
41.0 2729 2.25 1.33
41.5 2768 2.0 1.08
42.0 2806 1.75 0.88
120 grain Sierra SP
Charge (grains) Est. velocity (fps) Group max. diameter (in) Group mean distance (in)
38.0 2493 2.5 1.88
39.0 2559 1.75 1.08
40.0 2626 1.5 0.75
41.0 2693 2.75 1.67
Sorry about the data being offset; it didn't copy well from my word table.