Went to the range yesterday to shoot my first loads for a new 338 (24" Lilja barrel). Two batchs, both with RL19. One was with 225gr TSXs and the other was 210gr Partitions. Temps were in the low to mid 30s. Looking at my velocities (Oehler 35P) compared to the Nosler and Barnes manuals, they are all between 120 - 153 fps below what the manual says I should be getting. Is this temperature???

RL19 and 22 both seem temp sensitive to me but the velocity difference you report could easily be due to the particular lot of components used as well as the particular barrel.

I have seen some large variations in velocity from the books claim with loads that were fired in 70-80* F temps. The different components as noted in the above post can make quite a change at times, add the temp difference and what you`ve found isn`t at all out of the ordinary.

I saw a claim once that 2 fps per degree F is a good rule of thumb for the effect of temp on velocity. This has been close to my finding in the past with my loads reguardless of powder used when fireing the same loads over different time spans and temps. The new Hodgdon "Extreem" line seems to be better though in lower temps but still varies with higher temps (90+F)from what I`ve seen.

I've seen that much swing, especially when using large volumn cases & slow powders.

Antlers ----- All the manuals tell you is what that test rifle shot that load on that day, nothing more or less. Your rifle and load can be quite different, it is up to you to figure the personality of your barrel, loads, etc. Some manuals are closer than others, some are just plain wrong and hopefully were later corrected, as in the blue Barnes book. If it looks wrong, refer to another manual. I have ever manual published, and I consult all of them before starting on a load. Good luck and good shooting.

Temp., barimetric pressure, humidity, and elevation all are invloved. The other factor is your chamber and barrel- different dimensions for the throat etc. will alter the results. Maybe Dan got your barrel so slick and smooth it isn't building the friction of the test barrel used by the bullet company. Barrels are like people- all are different.