30-06 loads much slower than expected

[TargetTerror]

I'm getting much lower velocities for my 30-06 loads than I expected based on published data. I'm loading for a WWII Garand, and a Remington 1917 (1917 Enfield). The 1917 has been sporterized, but I think it is still the original barrel, which is 26 inches.

Components with all loads was Lake City Brass, CCI 200 primers, and IMR 4064.

My Garand data with a 168 grain SMK is (average velocity for 10 shot strings, giving the barrel time to cool in between):
43gr - 2185fps
45gr - 2285
46gr - 2359, 2385 (second string done on a different day)

My 1917 data with a 175grain SMK is (average velocity for 10 shot strings, giving the barrel time to cool in between):
47gr - 2473
48gr - 2558
49gr - 2597

Every load above is a good 200fps or more slower than pretty much every published load. I don't think my chronograph is off, b/c my Savage F/TR registers ~2800fps with a 175grain SMK (30 inch barrel, .308win).

Any ideas? What kinds of velocities are other people getting with IMR 4064 in 30-06? Neither the 46 gr load in the M1, nor the 49 gr load in the 1917 showed signs of pressure, though 49 grains is about published max.

 

[rcmodel]

Your Garand 168 load is just too low.

46.5 is a starting load @ 2,626 FPS.
50.8 is MAX at 2,850 FPS.

The 175 / 49 grain load is only down 100+ FPS from the data I am looking at.
Variations in barrels & powder lots can account for that much.

rc

 

[dakotasin]

barrel and chamber condition will account for some of the lost velocity as well (because a half grain more powder isn't going to gain you 300 f/s in any rifle case). i doubt either one of those barrels has a tight chamber...

 

[fguffey]

Both rifles? How old is the powder? Do have another powder? If speed picks up with a change of powder consider something is wrong with your IMR 4064.

If there was another rifle, in good shape, the ammo could be tested and a conclusion could be drawn. Maximum load with out signs of pressure would indicate the barrel was worn (loose). I hear it often, one rifle shows signs of pressure when using 2 grains less than maximum, this could be a tight barrel, someone else will say their rifle shoots it's best groups with 2 grains over maximum with no signs of pressure, could be a loose or worn barrel.

Risky!? If the barrel is loose back off on the powder and use 303 (.311) bullets then check the speed in the M1917 Enfield, you are on your own with the Garand.

Or you could slug the barrel to eliminate the bore.

F. Guffey