My .264 win mag loads are too slow


Dec 11, 2007
Put some starting loads together with 73gr H870 and Hornady 140 SST's virgin win brass was used and WLR mag primers seated to clear the magwell of my FN action 26" bbl. First go around chronoed a 2700 fps reading with a measurement of .517 just forward of the belt with a begining reading of .509 second string of 73.5 gr read 2736fps third at 74.0gr was 2738fps 4th at 74.5 showed 2752fps and 5th and sixth did not read, seventh string at 76.0gr came up at 2836fps with the same .517 ahead of the belt and a fairly flat primer but no cratering. I fired off some factory Winchester 140gr .264 win mag fodder and they show an average of 2798fps with identical flat primers and a .517 ahead of the belt with an initial reading of .509 as well. seems like it takes a full 2 grns of powder increments to observe a meaningful gain. I would like to get at least 3100 fps but will take at least 2grs more to realize this. I did not record groups as my mounting system failed me with not enough windage adjustment. What's with the low velocities as compared to the reloading manuals higher readings?
I just went back in my records. When I still had H870 I was getting 3220 FPS out of a 25.5" 1-8 twist barrel with a 140gr Speer Spitzer.

My 140gr Sierra SBT were 3090 FPS, but I was using 64gr RL25 then.

You should be doing better that that.

Oh CCI 250 primers were used.

I have a range day planned tomorrow with Retumbo. :)
I am shooting 59.5 grns of 4831 sc, 140smk with a r9.5 prime in winchester brass with a sami chamber. shoots 2930 with a sd of 7 and is a 6 shot one ragged hole group. it will shoot faster with more powder or r17 or r22 but not better.
To make that 264 mag move get you some Retumbo.
I have a Rem 700 with a Shilen 27 3/4" barrel in 264 WIN mag. and the load that I am going to try out deer hunting in two weeks is 66.5 grs Retumbo, WW case reformed from 7mm mag cases, CCI 250, 130 Nosler Accubond ten thousands off the lands, 3350 fps and it shoots in the .4s @ 100 yards.
I tried IMR 4350, H-4831, AA3100 but could not get the velocity with accuracy I was looking for. Then I tried Retumbo and bingo.
Retumbo & 140's in my rifle sucks. 64gr gave me 1 1/2 groups & 3050 FPS. Once I got to 66gr there was definite pressure signs in the case & about 4" groups. Did like the speed though 3180 FPS. Im sure if I went backwards I could tighten the groups up, but then I'd be hard pressed to get to the 3000 FPS range :( Never tried it with 130's though & that could be a different story.

RL25 is still my standby powder for the 264. Right now my best is @ 64.5gr RL25 with a 140gr Accubond & 3110 FPS average. I'm gonna get a hold of some US869 in a couple weeks & we'll see what that does.
With my Remington 264 sendero I never shoot anything but 100 grain ballistic
tips for deer hunting and have bagged them as far as 268 yards and all one shot kills they never took one more step.
My load is 68 grains of Reloader 22 at 3564 fps and very accurate 1/2 inch 5 shot groups at 100 yards. And this load is still at 2367 fps with 1244 pounds of energy at 400 yards optimal game weight still enough for 200 pound animal.
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