300 WSM reloading question

[mehus]

So I just got a new 300 wsm (Browning X-Bolt, love it!) and am working up an elk hunting round. I just spent some time at the range today with handloads and my velocity is nowhere near what the reloading manuals list. For example, the 180 grain x-bullet was supposed to generate 3036 at the max load of one powder. I got 2866. The 200 grain accubond was even worse--almost 200 fps lower on 3 different powders. Anybody offer any reasons why this is happening? Here are some observations on the day:

-Very windy
-Top loads did not necessarily develop top velocities. For example, one grain less than max gave best velocity from IMR 4350. This was true for 4 of 5 powder/bullet combinations I tried.
-None of the loads showed excessive pressure signs
-Weird clouds out. Very thin, high clouds. Maybe they affected my Chrony?
-FYI I would have expected not to hit top velocities as my barrel is 23" vs 26" test barrels. But 200 fps lower?

Any insight would be great, thanks!

[hoghunting]

You might want to try Alliant's RL-17 as it was made for the short mags. When working up my loads for the 300 WSM, RL-19 worked the best in my rifle with all the bullets I tried. I developed my loads before RL-17 was available, and will try it on my next powder run.

[thndrchiken]

Welcome to the world of reloading. Rarely will you get the velocities listed in the manuals. Most often the data is from a pressure barrel not actually shooting and chronographing the load. The are also usually listing the barrel length as 24".

[HEAD0001]

I use H-414 in my 300 WSM. Velocities (as you have seen) can vary greatly in different rifles and with different loads.

Were you having any pressure signs at max. loads?? Tom.