Quicksilver338
Well-Known Member
Heck even if it matches performance of the 28 but you get more barrel life out of it that's a win.
7-300 Norma Mag Improved. IT’S ALIVE!!
- Thread starter Huntnful
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Huntnful
Well-Known Member
Still obviously learning this cartridge and what charge weight for what bullet weights. So this evenings test wasn't ideal.
I was over pressure on the 190 LRHT's and H1000 in my once fired brass. Which I honestly thought I had enough cushion not to be. I was wrong.
85gr. yielded a bolt click and 3200fps right of the bat
I had 5 loaded at 86gr. for the little accuracy test. I still decided to shoot all 5 because that's what I was there for and it didn't feel that dangerous. Shot just under a 1 MOA 5 shot group at 400 yards. Decent bolt lift for sure, so not ideal conditions for accuracy being that far into pressure. But I did find out that H1000 is really consistent, even in this under filled case, and into pressure.
This is 5 shots at 86gr. H1000 and 190 LRHT's
I believe I would have to drop down to 84gr. or possibly even 83gr. to get out of pressure with the 190's. So realistic velocity probably around 3100-3140fps with H1000.
Then I shot the 160 Copper Rose with Retumbo. They shot just over 1 MOA at 400 yards for 5 shots. Also not ideal, since they were loaded in my old 300 NMI that I just necked down for testing purposes.
87gr. 3436fps
88gr. 3460fps
89gr. 3470fps bolt click
90gr. 3523fps heavy bolt lift
5 shots at 87gr. Retumbo
Basically we're all just learning this cartridge together lol. Everything is new to me also. So I'm just trying to test and document data for future possible interests in the cartridge.
I was over pressure on the 190 LRHT's and H1000 in my once fired brass. Which I honestly thought I had enough cushion not to be. I was wrong.
85gr. yielded a bolt click and 3200fps right of the bat
I had 5 loaded at 86gr. for the little accuracy test. I still decided to shoot all 5 because that's what I was there for and it didn't feel that dangerous. Shot just under a 1 MOA 5 shot group at 400 yards. Decent bolt lift for sure, so not ideal conditions for accuracy being that far into pressure. But I did find out that H1000 is really consistent, even in this under filled case, and into pressure.
This is 5 shots at 86gr. H1000 and 190 LRHT's
I believe I would have to drop down to 84gr. or possibly even 83gr. to get out of pressure with the 190's. So realistic velocity probably around 3100-3140fps with H1000.
Then I shot the 160 Copper Rose with Retumbo. They shot just over 1 MOA at 400 yards for 5 shots. Also not ideal, since they were loaded in my old 300 NMI that I just necked down for testing purposes.
87gr. 3436fps
88gr. 3460fps
89gr. 3470fps bolt click
90gr. 3523fps heavy bolt lift
5 shots at 87gr. Retumbo
Basically we're all just learning this cartridge together lol. Everything is new to me also. So I'm just trying to test and document data for future possible interests in the cartridge.
Huntnful
Well-Known Member
Also if you're wondering why I'm doing some testing in my old brass. It's because I'll never use that brass again, so if I'm way over pressure with an estimate, it wont matter. Because it's all getting thrown away. I'm just trying to find baselines with it.
And still I thought I was safe shooting my once fire brass with the 190's and H1000 and was dead wrong. Probably torched those cases lol. But live and learn. Only way to know is to actually do it and find out
And still I thought I was safe shooting my once fire brass with the 190's and H1000 and was dead wrong. Probably torched those cases lol. But live and learn. Only way to know is to actually do it and find out
It's amazing how a change in bore diameter increases pressure, I shoot my 300 NM with 215s over 87 gr H1000 and no pressure, decrease the bore 0.024 and it's a different ball game.
Hmmm how about a 230 at the same speed and barrel length?I might go to a 24" 5R, just because cartridge is quite a bit faster than I was anticipating and possible bullet blow ups once the throat starts cracking bad.
180's at 3200 from a 24" barrel sounds just right
Thats tad hot for norma. All ones i done are red lining 3050-3075 with 26" 230 bullets and n570
Huntnful
Well-Known Member
Absolutely dude. Pretty crazy to see the comparisons first hand.
From what I can correlate so far, the 180 ELDM creates pressure similar to a 225 ELDM or 230 Hybrid, in relation to powder charges.
So roughly:
92gr. N570
89gr. Retumbo
85gr. H1000
Seem to be similar for both cartridges with 180 ELDM and 225 ELDM.
And now from there, we can adjust charge weighs based off different bullets in the 7mm class.
Huntnful
Well-Known Member
That's freaking hot lol. All my 300 NMI's have been 92gr. N570 for about 3030-3050fps in a 26" barrel with a 230gr. bullet.
Huntnful
Well-Known Member
This just got put up today. Its was a great conversation about mule deer hunting as well as some rifle, optics and other gear talk also.
Huntnful
Well-Known Member
It may be possible. Wonder how it would compare. But I think these are realistic numbers with a 180 ELDM.
7-300 NMI - 85gr. H1000 3200FPS
28 Nosler - 83gr. N570 3100FPS
Rick Richard
Well-Known Member
Are you monitoring or measuring your throat erosion during all this testing? It would be interesting to see the amount of throat erosion over the total shots fired….just for the heck of it and you are testing at your expense for us. lol.
have you tried n568? I have been pretty happy with it in the lapua, burns cooler than N570 and it has really good case fill for the big magnums.
Don't mean to get too far off topic on Huntnful's thread but how are you guys that are pushing the top end loads determining what the max charge weight is for your rifle. Are you simply looking for stiff bolt, ejector marks, flat primers, or are you measuring the case head before your brass is fired and checking the expansion of it after to see how much it grew.
I know with all the tough brass out there, and actions that are built to such great tolerances pressure can be difficult to spot at times. If you had a single shot action without an ejector, you wouldn't have that tell tell ejector mark to go by. By the time you had a stiff bolt in that scenario I'm betting you'd be way over pressure.
Just curious as to what others do to find their max loads, especially when playing with some of these wildcats.
I know with all the tough brass out there, and actions that are built to such great tolerances pressure can be difficult to spot at times. If you had a single shot action without an ejector, you wouldn't have that tell tell ejector mark to go by. By the time you had a stiff bolt in that scenario I'm betting you'd be way over pressure.
Just curious as to what others do to find their max loads, especially when playing with some of these wildcats.
