7-300 Norma Mag Improved. IT’S ALIVE!!

The ugly truth of mega overbore hahaha. 123 rounds in. Some decently fast paced shooting I guess. But all my 5 shot groups were shot over 5 minutes. And I always waited at least 5 minutes between groups with the barrel cooler going and 40 degrees outside.



We'll see what being a little more cautious and with H1000 does in the next barrel haha.

Did you have any bullet blowups?
 
Wow…That looks like a 300 nmi with 800rds on it!
It really does hahahaha.
Did the bullets magically stop landing on point of aim or did I miss something?
Nah they still shoot. But I don't know how much longer lol. I'm just getting the new barrel chambered because that's the one I wanted to hunt with if I liked what I was seeing from the cartridge.
Did you have any bullet blowups?
No blow ups yet
 
Alligator skin rifling is the new fad don't you know?

I'm kind of the same boat with the barrel situation as well. I have a middle ground barrel that's half experimental. If I like what I see then I'll be diving in with both feet.
 
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Alligator skin rifling is the new fad don't you know?

I'm kind of the same boat with the barrel situation as well. I have a middle ground barrel that's half experimental. If I like what I see then I'll be diving in with both feet.
Yeah I really had no realistic intentions of getting a 7-300 chambered in February and using that same barrel in October for hunting lol. I knew I wanted to test a pile of stuff in it to see plausible performance.

What I really wanted to see is if it would edge out a 28N, but with H1000. I've really grown to like that powder a lot. And at least in this barrel, it had super low ES, best accuracy (small test), and some pretty decent speeds also. So I'll commit to it, even it takes another barrel or 2 before season haha.
 
Using the brux as a fire forming barrel since it looked toasted and I got more barrels coming. This is 55 STRAIGHT rounds. As fast as I could shoot them.

IMG_2061.jpeg


First 3 shots went into one hole and first 10 landed into about a .6-.7" group. And all the far outliers to the upper left were probably the last 10 rounds.

So I'm not sure about the jacket failures specific with 4 groove barrels, but I'd imagine this is worst case scenario. Alligator throat and blazing barrel. Except they're only going 3010fps for fire forming.

Might buy another one these Brux's though. Thing freaking hammers lol.
 
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Using the brux as a fire forming barrel since it looked toasted and I got more barrels coming. This is 55 STRAIGHT rounds. As fast as I could shoot them.

View attachment 550759

First 3 shots went into one hole and first 10 landed into about a .6-.7" group. And all the far outliers to the upper left were probably the last 10 rounds.

So I'm not sure about the jacket failures specific with 4 groove barrels, but I'd imagine this is worst case scenario. Alligator throat and blazing barrel. Except they're only going 3010fps for fire forming.

Might buy another one these Brux's though. Thing freaking hammers lol.
Exactly what I'm doing with my barrel. I've got 50 hydro formed Lapua brass loaded for fire forming.
My Proof barrel is toast and will serve as the sacrificial fire forming rig.
It's how I've been doing it for the last 2 barrels with this reamer design
 
Here's a thread on LRO talking about grooves and jackets and splosions.

 
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