Quicksilver338
Well-Known Member
Curious what a short barreled version of this rifle would do for performance. Compact package, lighter weight, but still long range lethality…if you get bored
7-300 Norma Mag Improved. IT’S ALIVE!!
- Thread starter Huntnful
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It would be a slower velocity barrel burner
Quicksilver338
Well-Known Member
For sure, but would the performance be worth it if you wanted a compact package? VS a short barreled short mag for example. Even though it's neutered, it should still shine well above everything else.
I mean ya it'll outperform any 7mm on market. I dont think rum can get a 180 too 3400
WeiserBucks
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I'm picking up a 20" 7 RUM in about two weeks, we'll find out.
Why 20"? Because 10.5" suppressor that's why.
Huntnful
Well-Known Member
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
A 7rum has 2gr more capacity H2O than this case with the samples I have here at the shop.
I played with the 7rum years ago and ran the 180s around 3350. That was using US869.
That was also using Remington brass and I don't stand on things like some folks do.
Kirbys 7 Allen mag (7-338 lapua imp) will have another 14gr or so capacity over this one if we are wanting to crown the biggest 7mm, that would be it.
Grossly overbore magnums always leave me disappointed in the end though.
Huntnful
Well-Known Member
Are there any instances where a case with slightly less H2O capacity will outperform one with more capacity, do to its design differences?
There are lots of theories about internal ballistics and case design.
Things I do know is: as case capacity goes up, efficiency goes down. And there is no replacement for displacement!
I believe that the improved cases just do a better job at hiding pressure. Less body taper will create less bolt thrust and will take higher pressure before you get to heavy bolt lift.
You're shooting a bat action with .998 tall lugs, a 1.121 tenon barrel and lapua brass….I'm guessing those velocities you are seeing are on up there pressure wise.
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Huntnful
Well-Known Member
That all makes perfect sense. I appreciate the clarity. And I agree, they seem fast for sure. I bet you could quite a ways into pressure and not even realize with this setup.
Huntnful
Well-Known Member
I know this is unconventional compared to what the majority of people do, but it's worked great for me for testing bullets and powders.
I have what I believe is 5 rounds loaded below pressure, to help with accuracy, because that normally shoots better than when I'm near pressure. And then a small charge weight test.
I do the charge weight test to foul the barrel, with that specific bullet and powder combo, and then shoot the 5 shot group to see a potential of how that specific combo is going to shoot. Bullets are about .015 - .020 off the lands. Shoot it at 3-400 yards.
I've haven't really seen any truly significant increase in accuracy from small powder charge changes, or small seating depth changes.
So this baseline test normally shows me whether or not the bullet is going to shoot well in the gun, with a specific powder. And if it does shoot well, and I have room to add a little powder, I will.
I have what I believe is 5 rounds loaded below pressure, to help with accuracy, because that normally shoots better than when I'm near pressure. And then a small charge weight test.
I do the charge weight test to foul the barrel, with that specific bullet and powder combo, and then shoot the 5 shot group to see a potential of how that specific combo is going to shoot. Bullets are about .015 - .020 off the lands. Shoot it at 3-400 yards.
I've haven't really seen any truly significant increase in accuracy from small powder charge changes, or small seating depth changes.
So this baseline test normally shows me whether or not the bullet is going to shoot well in the gun, with a specific powder. And if it does shoot well, and I have room to add a little powder, I will.
Looking forward to your thoughts on this boomer vs. the 28 Nosler.
Its tight race. 28 nosler coming in at 300 rounds 7-300 norma 250.
Huntnful
Well-Known Member
So basically it looks this cartridge, with a mild load with out perform at 28 Nosler at a MAX load, by what appears to be 100 fps. If you take the 7-300 up higher, it'll go 200+fps faster. All at a cost of barrel life of course. But I like mild charge weights and lapua brass. Which is why I wanted to test this out.
Basically I wanted to see if the 7-300 with decent charge of H1000 or Retumbo, would beat out a 28 Nosler with max charge of N570.
I know started the testing with Retumbo and N570, just because I wanted to see some potential. But if I settled on a charge of H1000 and a 180gr. bullet at 3200fps, I would definitely be happy with that.
