Tonight I shot my 300 winny some more. Chronied more loads too.

180 Barnes XBT , Retumbo
78----2963,2969
79----3003,3002
80---3051,3091



165 Partition H4831
77----3191
78----3204
79----3282
80----3289
80.5----3299,3303

It looks like you're quite a ways under max with the 180 loads. Did you stop because of pressure signs or just haven't tried anything more yet?

It looks like you are using the wrong powder. With my 300Win Mag I get 3150 FPS with 71.5gr of
Imr 4350 using the 180gr bullet. My barrel is 25". Hope you find the problem.

For me the case is full at 80 grains of Retumbo and the barnes 180 xbt. (federal cases).

I may try the 4350 with the 180 grain bullet. I want to use H4350 but dont have any right now.

RMiller, get Lapua 300 WM brass - it'll take ~90 grs. of Retumbo. Hodgdon recommends 84 grs. of Retumbo with 200 gr. bullets. You're very mild with that 180 gr.load. I've loaded up to 89.0 grs with 180 gr. Nosler BTs and settled on 88.5 grs giving ~3250 fps with a 26" barrel. That's a max load at about 65,000 psi.

The nosler ballistic tip is also a much shorter bullet too.

When I loaded 200 TSX with 80 grains of retumbo the bullets would not stay seated from the powder pushing them out.

The main difference is Millers chronograph works!

Here are some more loads.

IMR 7828 180 Barnes XBT

75----3038
76----3101
77----3130
78----3163, 3173 These are getting warm

IMR 4350 180 Barnes XBT

70----3046
71----3117
71.5----3112
72----3166, 3177


The 4350 loads had less recoil too.

Shot some 220 sierra mk with win cases and cci 200 primers

IMR 7828
68----2681
69----2699

72----2833

four shots 70 x 1, 71 x 2 and another at 72 x1
gave 2762, 2769, 2835,2834 but I don't know which ones were which because the cases werent marked.

There's no way I'd burn 80 grs. of powder to achieve a little over 3000 fps. Not when you can load a smaller charge of Reloader 22, IMR 4831, H4831, or Winchester WXR and get the same or better velocity. Big powder charges increase recoil and shorten barrel life.

AD

Allen Day I agree.

With the 180 XBT I got the highest velocities with IMR 7828 and IMR 4350 . IMR 4350 did it with a bit less powder and recoil too.

H 4831 got the same velocities as Retumbo but with 76 grains rather than 80 for Retumbo.

I use 78 grains Reloader 22 with a 165 grain Barnes XBT. Hornady 150grain Interbond does very well also with 78gr. Reloader 22