My results in 300WSM

Donut Slayer · Posted: Mon Jun 14, 2010 6:59 pm Post subject: My results in 300WSM

OK, here are my chrono results of my 300WSM. Please dont just load these and go shoot. They are safe in my rifle, but may not be safe in yours. Back off several grains and work your way up. Sierra says 69.0 is the MAX for a 180 gr bullet. That shows pressure signs in my rifle. I only chrono rounds that shoot MOA or better as I dont care how fast it shoots, if it wont group, I wont mess with it. All velocities are FPS.

300WSM
RP cases
Win LR Mag primers
IMR4831
Sierra 180 SPT(flat base)
Rifle: Win 70
temp 90 degrees 80% humidity.

67.0gr
#1 3066
#2 3092
#3 3091

68.0
#1 3141
#2 3125
#3 3131

69.0
#1 3186
got a sticky bolt, and cratered, flattened primer. stopped and pulled the bullets.

Sierra 180 SBT(boat tail)

67.0
#1 3107
#2 3131
#3 3113

68.0
#1 3168
#2 3151
#3 3159

Sierra reloading manual says 69.0 is max, but I got pressure signs in my rifle. I comfirmed the info with Paul Box at Sierra. Its funny how the boat tail bullets are faster than flat base with the same powder charge. There were virtually no POI difference with the 2 bullets @100yds. No pressure signs at 68.0 gr at all. All loads shot under MOA.

Elvis · Posted: Mon Jun 14, 2010 9:30 pm Post subject: Re: My results in 300WSM

looks like great deer medicine.

slimjim · Posted: Tue Jun 15, 2010 2:38 am Post subject: Re: My results in 300WSM

Those are some pretty consistent velocities plus your getting about 150 fps more in velocity than Hodgdon load data suggests for your 24-inch barrel. I wish my barrels would do that - you must have a good one.

Boat-tail bullets typically have less bearing surface/friction than a flat base of the same weight. Changes the internal ballistics enough to notice the difference.

tikkat3 · Super Member Joined: Jul 30, 2006 Posts: 800

I 'm getting 2,890 with RE22 and Nosler 180grn Partitions

stovepipe · Posted: Thu Jun 17, 2010 10:32 am Post subject: Re: My results in 300WSM

Nice tight speed groups @ 68gr. Good attention to detail no doubt.

Good stuff! Wish I had a chrony sometimes. Darn shoestring budget.