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Best Reload Combo for the 300 win mag?

F

Fist13

Copper BB
Im new here and so I didnt see this topic yet. What is the best bullet/powder combo for accurate shots. Id also like to know if I could get these rounds out past 500 yards too.
 
As far as components it is sort of rifle dependent. Just start with popular published data and go from there......find something that works or you can spend an eternity fine tuning loads all the time. ….I like somewhere between.

As far as yardage, you can shoot a 300 WM 1000+ yards if you like and bag thin skinned game reliably......load dependant.
When the military only ran 30-06 they were reliably killing humans at 1000+ yards so....you’re basically shooting a 30-06 magnum
 
I figured that someone who has a mossberg 4x4 300 win mag may have found something already that i could try. I just made my first loads the other night and shot them today. They jumped around about as much as any other set of ammo. Im wondering if there could be something wrong with my rifle/scope. I know this was my first set of reloads but ive been having problems even with factory loads jumping around on me with this rifle.
 
any suggestions? Like asking mossberg to look at it or getting rid of it and trying something else? Im also curious if I have to put the neck all the way to 1/2 way up the cannelure on the bullet or if i can go right up to the bottom of it.
 
180gr. hornady sst, h4831 powder 72 gr. Im working on my next batch i checked the length of all my brass. There's a lot of difference there in some of them. Im using once fired stuff, RP and Fed. Fed primers although i may try cci soon. This time I but a bullet in an empty case and closed the bolt on it to see where it sat and marked it. Im going to set the bullets to that height for now unless told otherwise. I was told by someone to go 1/2 way up the cannelures but I was thinking if it didnt have one anyways I could go further down the bullet, hence why im trying it this way this time. And I lightened the powder to 70 gr.
 
I had a couple groups that were probably between 1"-2" and others as far as 1"-2" first two shots then a 6"-8". Some of the groups are just 6"-8". Im a military guy so i know when i have bad mechanics on my part and I know when I "pull" shots about where they're going to be but some of these odd ball shots were pretty surprising. Im using a 4-12x40(maybe 42) bushnell banner as my scope.
 
Fist13 said:
any suggestions? Like asking mossberg to look at it or getting rid of it and trying something else? Im also curious if I have to put the neck all the way to 1/2 way up the cannelure on the bullet or if i can go right up to the bottom of it.
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apparently when I asked this question originally I hit the edit post button instead of quote button, hard to see on my phone, so the comment below is actually from april 1 somewhere between 8:30 and 11:00:

What kind of groups are you getting? What types of bullets are you using? My.338 seams to like flat base bullets better than boat tail. I wouldn't give up on it just yet, but if you take a look at my build thread I've been trying some various things with mine to dial it in.
 
Fist13 said:
I had a couple groups that were probably between 1"-2" and others as far as 1"-2" first two shots then a 6"-8". Some of the groups are just 6"-8". Im a military guy so i know when i have bad mechanics on my part and I know when I "pull" shots about where they're going to be but some of these odd ball shots were pretty surprising. Im using a 4-12x40(maybe 42) bushnell banner as my scope.
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That sounds similar to the results I'm getting with mine except for worse. I've been trying all sorts of stuff to get mine to shoot better, I even went as far as glass bedding the action. I've gotten nowhere. I'm going to continue to fiddle with it for a while, but I may end up having a smith look at it. Your best bet may be sending it back to Mossberg.
 
With my 338wm, the two things that make is shoot well (assuming I do my part) is using epoxy (JB Weld) to bed the magazine well/holder piece into the stock, and cleaning the copper fouling out of the barrel. Mine copper fouls within 10 rounds and is badly fouled in 15. I've tried a couple different brands of bullets and they all do it. The bore is rough and the machining marks 90* to the bore are plainly visible with a flashlight. Look for heavy copper streaks in the end (muzzle) of the bore.
 
Are you full length sizing or just neck sizing? Gotta full length size if these came out of other peoples guns until you fire the ammo from your chamber.

Are you keeping your brass sorted by headstamp while developing your loads?

Are you case trimming your brass after full length sizing? If you didn't and you tried seating to the cannelure on each case then your OALs are all over the place. And you can't trim fired brass and then full length size. It screws up the length all over again.

Just some random thoughts and observations.

It sounded to me that you are using cases that are various lengths, and varying capacities, and also are not sure about bullet seating depth that your rifle prefers.
 
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