7-300 Norma Improved project update

[nodakhunter]

So after my initial thread wondering about the pros and cons of doing an extreme 7mm build, the 7mm-300 Norma, and receiving a lot of comments that it was a bad idea, I've decided to do a 300 Norma Improved instead. I hear a lot of good things about this cartridge and its ability to push heavy 30 cal bullets. My plan once this is all said and done is to have a fairly lightweight, long range elk killer.

I'm currently in the process of getting a reamer print (JGS) drawn up. I'm planning to run either the 215 or 230 grain Berger Hybrids (for hunting) and maybe try out Hornady's 230 A-tip for stretching the rifle's legs a little bit. I'm undecided about what to do with the freebore on this rifle. From everything I can find, somewhere around .210-.220" seems to be about right for the 215 and around .260" for the 230 grain class of bullets. Any opinions about which route to go?

 

[Mram10us]

Have you considered the 250 class bullets?

 

[Rhovee]

IMO 230's. If you have a bullet going over 3100, time to step it down to something bigger. I wouldn't expect much gain from accuracy between a 230 A tip and 230 Berger. I have a 300 NMI and a 338 NMI. I would go .260-.275 FB and try the new 245's and see what you can come up with as well. 215 is a great bullet, but traveling north of 3150 would be a huge mess if shot something within 300 yards.

 

[nodakhunter]

IMO 230's. If you have a bullet going over 3100, time to step it down to something bigger. I wouldn't expect much gain from accuracy between a 230 A tip and 230 Berger. I have a 300 NMI and a 338 NMI. I would go .260-.275 FB and try the new 245's and see what you can come up with as well. 215 is a great bullet, but traveling north of 3150 would be a huge mess if shot something within 300 yards.

That's kind of along the lines of what I was thinking. Those new 245s coming out of the barrel around 2950 sound enticing too. Do you have any problems loading the rounds to fit your magazine? Planning to run an Accuracy International CIP length mag.

 

[nmbarta]

Pretty sure Ryan Pierce has that one figured out. You might want to give him a call. Decent chance it'll be tough to come up with a better reamer, but it doesn't hurt to try.

 

[GCarlton53]

Since when is overbore a bad idea? A 7-300norma with a 180gr berger. Sounds tasty

 

[IdahoCTD]

Pretty sure Ryan Pierce has that one figured out. You might want to give him a call. Decent chance it'll be tough to come up with a better reamer, but it doesn't hurt to try.

Believe it or not it was figured out before Ryan built his first one. Just because the rest of us don't build guns for a living doesn't mean we didn't have it figured out. My reamer was made in 2014 or 2015.

 

[nmbarta]

Didn't say he was the one that figured it out, I said he has it figured out, meaning that he can build a very nice rifle in that cartridge and do so with the specific bullets optimized in that case that the op inquired about.
Every time a new cartridge is introduced to the market, hundreds of gun smiths start looking at how to make it better, which is a beautiful thing. It makes hard to know who did anything first.
There were probably 50 guys, maybe more,that had almost identical ideas within a week of the 300 norma being released.
You very well may have been among them, and may do just as well or even better for all I know, just never heard of you or your knowledge of this cartridge, so I couldn't have mentioned you.

 

[nodakhunter]

Since when is overbore a bad idea? A 7-300norma with a 180gr berger. Sounds tasty

I know, I know.....just didn't want to risk blowing up bullets, especially in a hunting gun. Didn't want to risk Murphy's law coming into play with a big elk in the crosshairs.

 

[Mram10us]

Believe it or not it was figured out before Ryan built his first one. Just because the rest of us don't build guns for a living doesn't mean we didn't have it figured out. My reamer was made in 2014 or 2015.

Reminds me of Carlock getting the credit for the Edge, when it was built by others before him. Granted, both have a good handle on them.

 

[IdahoCTD]

He gets credit for the name though. Swamplord did his version just before me and I guess because he didn't talk it up and build guns his name didn't catch on. People harassed him enough you don't hardly see him on here anymore.

 

[Mike D Texas]

Since when is overbore a bad idea? A 7-300norma with a 180gr berger. Sounds tasty

Or a Berger 195 EOL.

 

[RH300UM]

I run both the 180 hybrids and the 195s in our 7rbh(7/300 NM imp)
8.4 twist barrel
195's @ 3250fps
180's @ 3300fps
Both can pushed faster but accuracy suffers. Also the N570 issue of accelerating throat erosion has put Retumbo in the top slot for now.

 

[nodakhunter]

What bullets work best for you in the 300 RBH?