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.

 

[Fixxah]

WHat kind of shape is the bbl. in? Have you tried them in another gun? Just a thought.

 

[BIG GUN]

A lot of data is based on using a special pressure barrel. every firearm is unique and the published data is only a reference. If you are shooting paper targets, they don't care about a difference in velocity so don't worry about it.
Just go for best accuracy.
4064 & 4895 along with Varget are the powders of choice for the Garand.

 

[TargetTerror]

Yea I know that accuracy is generally more important, but I hope to shoot both of these rifles at 600 yards, and 200+fps can start to make more of a difference at that distance. Both in terms of drop and windage.

 

[DukeInFlorida]

Just dealing with the first load first:

Using a 168 grain bullet, which most of the time (for that weight) is a match type boat tail hollow point, which is a fast flying bullet......, the bullet has a ballistic coefficient of .534.

Using 45 grains of IMR4064, which is the starting load, should yield a muzzle velocity of 2367 feet per second, and at 100 yards, the velocity should be about 2200 feet per second, with a .1293 seconds time of flight. Depending on where your chronometer is, you'll need to adjust appropriately. At 500 yards, the velocity is approx 1625 feet per second. If sighted at 100 yards to zero, the drop at 500 yards is approx -74.6".

49 grains of IMR 4064 (the MAX load) should yield a muzzle velocity of 2549 feet per second, and out at 100 yards that would be approximately 2490 feet per second, with a .1240 seconds time of flight. Again, depending on where the chronometer is, you have to adjust. At 500 yards, the velocity is approx 1800 feet per second. If sighted at 100 yards to zero, the drop at 500 yards is approx -63".

So, for the 168 grain bullet, yes, you are a little slow.

I'd have to work out extrapolated data for the 175 grain bullet, which is not at all a standard bullet, but your numbers also look slow there.

How OLD is the powder? How accurately are you dispensing it? What type of powder measure are you using to dispense it?

 

[TargetTerror]

Thanks Duke. I use this online ballistic calculator, which seems to be pretty good:

http://www.eskimo.com/~jbm/cgi-bin/jbmtraj-5.0.cgi

The 175 grain SMK is pretty standard for long distance .308 shooting, from what I gather. Thats why I'm shifting over to it.

 

[DukeInFlorida]

Yup, pretty neat calculator. A buddy of mine showed me his.... iPhone with a built in app to also do the calculations.

But, you didn't answer my questions.

Old powder or new powder?

and how are you dispensing it?

I'm going to suggest that if you are using a DISK type dispenser, that you'll always be off unless you weigh it. Those are never ever accurate.