Home Forums Reloading Big Game Rifles Talk to me about the .300 Winchester Mag

I finally have a .300 win mag on order. It's a heavy barrel Savage that will be used mostly at the range, also for some stand hunting for whitetails. I have done a ton of shooting and reloading with the .308 and the .300 sav, but I am completely new to the .300 mag.

What I want to do is develop a mid-range load that will work for my purposes and will not work the brass overly hard. My plan, and ya'll stop me if I'm wrong, is to get some regular ol' FL sizing dies (probably RCBS), and set them where the shoulder is only pushed back ever so slightly on resizing. I want the cartridges to headspace on the shoulder, not the band. It's basically what I do with my other cartridges anyway, but I'm reading that the .300 mag is especially hard on brass if you aren't a little selective in your reloading techniques. My plan is to shoot 180-190 g. bullets at around 2900-3000 fps.

I have on hand H4831SC and H4350. I also have H4895 and IMR4895, but thinking these are gonna be a little fast burning for the caliber. I have Federal 210M primers that work wonderfully in the .308, but I'm thinking I should step up to 215M for this caliber.

Can you give me some specific advice on loads with these general parameters? I am open to all experience/suggestions. My main observation is that I'm not trying to push the .300 mag to the limits of its potential. Even loaded weakly, it looks like it will smoke the .308 in terms of performance.

Of course, I also note that there is so much case capacity, it probably will not be particularly accurate with light charges. I want something middle of the road that is going to be tackdriving accurate, but easy on the brass and easy (as a .300 mag can be) on me. In fact, I'd say that accuracy is probably gonna be my primary consideration.

As always, thanks much in advance.

I think you've pretty well got it covered. I run a 200gr bullet at 2900fps using I4350. A friend runs 180's in his at 3000+. Again using I4350. Neither load was what I considered red lined or near. Mine is a Rem and his is a Sako. Both rifles were quite accurate. 'Course you're getting into the area where you're gonna have to practice regularly to be able to accomadate the added punch of the rifles.
If you keep things in that bracket, I don't think you'll have any worries about brass longevity.

You dont need a 215 primer for the 300 Win Mag, I use WLRMs or WLRs, 75.5grs RE22 with 180 Hornadys.

gorskij took the words out of my mouth, the only difference is that i shoot 180 nosler with 75.5gr rl 22. I use mag primers in it but shoot rem 9 1/2 in my 7mm rem and it is more accurate with them than mag primers

I don't have a 300 Win Mag but I have a 308 Norma Mag. I use the same reloading technique you describe but with CCI LR primers, 4831SC and a180 gr Sierra GK Boat tail. I don't know how fast the bullet is going but I developed a nervous tick while working up the load.

Alan

I used to reload for a couple of rugers. It seemed I was trimming the necks a lot. I don't know if it was the brass, the chambers, the dies. I always thought about getting RCBS x dies for a 300 win mag if I did it again. Other than that it sounds like your on the right track.

I have been shooting the 300WM for decades, I prefer the Redding dies over the RCBS..yes headspace on the shoulder and forget about the belt.

Had many over the years and all have liked RL22 with 180grainers, my current most favorite load is H1000 with Berger 210gr VLD's

both my 300 win mags Love 75.5 grains of R22 and a 180 grain bullet. My savage 111 seems to like a 180 grain sierra pro hunter and my new Savage 111 heavy barrel (might be the same one you ordered) likes a 180 grain Nosler Ballistic tip bullet which shoots so good I don't want to switch to a berger vld like I originally planned.

I agree with all of those who said 75.5 gr of RL-22.

RL22 works extremley well in the 300WM , but I will say that I get tighter groups with Fed 215's when using RL22 not so much when using 210"s, but IMR 4831 and Fed 210's behind a 180 Accubond will suprise you as will H1000 behind a 185gr, Berger VLD!

I went with the 110 with the HS Precision stock. Looked at the 111 LRH, but I'm really just not wild about the accustock when it comes down to it. The 111 has that built-in muzzle break, though, and I'm wondering if that's a feature I'll eventually want on the rifle. I generally detest the things due to the noise, but there seem to be a lot of ppl with the .300 mag that use one.

Thanks for all of the input thus far. The Re-22 does seem to be a recurring theme everywhere I look.

Ditto on the Rl22 load in 300WM....and the Fed215's as well.RL22 seems to like Fed215's. I have noticed this even in the 270Win and 7RM with R22.

I've settled on a good middlin' load with a 168 TSX that is not making my ears bleed. It is 75 grains of RL-22 ignited by a Federal 210. Works fine. Shoots 3 into 3/4" at 100 and kills deer and moose like lightning bolts from heaven.

I also have used a load from an old Speer manual that was the intermediate load for 180 grainers. It was 4 grains beyong max in the Hornady manual (a later version.) It was safe in my rifle. I used IMR4350, and was getting 3140 ft/sec out of my rifle. The Hornady 180 BTSP was too frangible on deer with that load, so I turned to Barnes 168 TSX, and they work well.

I also found a load for 180 Partitions with H4831SC that shot well -- under an inch for 5 shots, and the velocity was north of 3000 as well. Good killer, and a good bullet.

If you're lloking for some lighter loads, IMR and H4895 will do you fine. I load some for a recoil sensitive friend that he loves, and he has killed a few deer with them as well -- 165 Hornady SP at about 2900, IIRC.

Wishing you good success with yours.

Have used the RL-22 load (75.5gr), CCI250, with a 180 BT @ 3023fps.
Got better accuracy with Ramshot Magnum (85.0gr)@ 3110fps.

JB has turned me onto the Ramshot powders - Big Game, Hunter, Magnum, etc. They dispense really well and seem to be very good in the accuracy and velocity dept for a lot of calibers that I reload for. The real trick is finding the darn stuff!!

PS - for an light recoil practice load, try some Trail Boss. 25.5gr behind a 150 Nolser BT = 1950fps - kicks like a .223!

IMR 7828 is no sleeping dog.