300 Norma Mag Improved. Follow along!!!

It's nice that it's daylight so early I can actually shoot before work haha. Yesterday I tried seating bullets a little deeper, and groups opened up slightly. I didn't have any bullet seated longer to test out though.

Today I seated some bullets extra long and just seated them to depth at the range. The bottom group was my original starting load. I adjusted up and then tried .01 longer and .025 longer. It got rid of the vertical with .01 longer depth and maintain a pretty good group considering how windy it was. I was holding .2 Mils left for every shot.

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Also, the velocities over the last 18 rounds while testing the 225's.
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Most of my accuracy loads with the 225 ELD-M's in 300 PRC's and for the 300 Norma Mag have been between .060" to .120" off the lands; usually about .080"-.090" off the lands being a sweet spot in the rifles I've loaded for. The ELD's seem to wanna jump more distance than Berger's from my experience. Just a recommendation.
 
I get that! A benefit to doing the test anyway would be finding your window or seating depth node. You could load on the lower side of it and be able to let the lands grow while still working through your accuracy window.
I completely agree! Which is why I'm still going to do the test. And I'll seat them at the longest accuracy node.
 
Most of my accuracy loads with the 225 ELD-M's in 300 PRC's and for the 300 Norma Mag have been between .060" to .120" off the lands; usually about .080"-.090" off the lands being a sweet spot in the rifles I've loaded for. The ELD's seem to wanna jump more distance than Berger's from my experience. Just a recommendation.
Oh wow, I'm definitely not that far off the lands. Definitely something for me to keep in mind if I don't find consistent accuracy!
 
Try a 3-shot group with them the next time you go to the range about .090" off and you might be pleasantly surprised :)
I'm going for the seating depth gold on my next range trip. I went up to 92gr. of N570 since 91gr. had no pressure signs. More case fill, more velocity, more gooder lol.

These are all seated at the max length I saw decent accuracy at. So it's only going deeper from here. And I'll seat them at the range. And I'll try an extra deep one also to see how it goes!

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I'm going for the seating depth gold on my next range trip. I went up to 92gr. of N570 since 91gr. had no pressure signs. More case fill, more velocity, more gooder lol.

These are all seated at the max length I saw decent accuracy at. So it's only going deeper from here. And I'll seat them at the range. And I'll try an extra deep one also to see how it goes!

View attachment 377226
I've had really good luck in determining seating depth by using the Berger method. I have never found SIGNIFICANT success when changing seating depths incrementally. My experience anyway.
 
I've had really good luck in determining seating depth by using the Berger method. I have never found SIGNIFICANT success when changing seating depths incrementally. My experience anyway.
I agree Rick. There seems to be a decently wide window where they shoot GOOD, and it's easy to find going .02 or .03 at a time. Then you can get crazy with the micro seating adjustments if you want from there. But if your gun wants .07 and your start at .02 in .005 increments, you're in for a long day 😅
 
I just figured it out, that I got my gun on June 17th. I've since made 13 range trips and shot 236 rounds through it (including the 100 fire forming loads). I'm assuming I'll be around 300-350 rounds in before hunting season. I should get two full seasons out her hahaha.
the way you're going you'll need a barrel by sept 1 2022 LOL
 
In my seating depth tests, which is one of the first things I do after finding my max pressure, I load what I know will be safe pressure, then I usually start at .005" off, and jump .015" at a time out to .110" off, which is 8 groups, 2 or 3 shots, so 16-24 rounds. This almost always yields obvious results, or at least a range it likes to be in. Then I fine tune my powder charge with a ladder test, then I fine tune seating if needed. With a good gun, I usually have a .5 MOA or less load in 50 rounds or less with this method. Sometimes things change though, if I have to switch primers due to not getting consistent velocities or something, that number can quickly go up!
 
In my seating depth tests, which is one of the first things I do after finding my max pressure, I load what I know will be safe pressure, then I usually start at .005" off, and jump .015" at a time out to .110" off, which is 8 groups, 2 or 3 shots, so 16-24 rounds. This almost always yields obvious results, or at least a range it likes to be in. Then I fine tune my powder charge with a ladder test, then I fine tune seating if needed. With a good gun, I usually have a .5 MOA or less load in 50 rounds or less with this method. Sometimes things change though, if I have to switch primers due to not getting consistent velocities or something, that number can quickly go up!
An excellent method!! And having to switch primers & powder on my 181 load development definitely took some extra time and rounds during that load development. Just glad it was suggested on here!

Meanwhile the 225's will tune up pretty quick it looks like. Only 18 rounds into the 225's. It took 118 rounds for the 181 hammers haha.
 
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