Barrel length on a big 30...

[ISS]

I have found data on the 300 NM with heavy bullets.
But, it is all done using 24" barrels.
Max loads show the 230gr Sierra at 2800fps. The 245 Berger is about 2650.
Realistically, how much would y'all expect a 30" barrel to increase those numbers?
3000fps?

thanks,

ISS

 

[Mike TackleBerry]

25 fps per inch give or take, depending on the powder you use.

 

[ISS]

Thanks Mike! You are a solid reference point.
A load that is under max in a 24" at 2800 or so will provide me with that Holy Grail of 3000fps.

 

[Sgt. Brumbaugh]

300 Norma with a 30 in barrel will comfortably push 245's at 2900+ and not kill the brass doing so. Some barrels are a little faster.

 

[Jr solocam]

I have a 28" RUM that shoots 230 Bergers at 2875 with H1000. Not max. With the 300N it will be higher especially with N570 or similar powder.

 

[SKWERLZ]

You should be able to hit 2850-2900 with a 245 with a 30”.

 

[SKWERLZ]

I have a 28" RUM that shoots 230 Bergers at 2875 with H1000. Not max. With the 300N it will be higher especially with N570 or similar powder.

Actually 300NM has a bit less case capacity than the 300RUM

 

[FeMan]

I get in the high 2800s with Retumbo and low 2900s with N570 in a 30-inch with 245 LRHTs.

 

[ELR LVR]

I have found data on the 300 NM with heavy bullets.
But, it is all done using 24" barrels.
Max loads show the 230gr Sierra at 2800fps. The 245 Berger is about 2650.
Realistically, how much would y'all expect a 30" barrel to increase those numbers?
3000fps?

thanks,

ISS

I've found once you get to 28 inches, the velocity gain tapers off to maybe 15 fps per inch. the longer it is.
This could be more caliber specific though
25 fps/ inch is a good realistic number

 

[SKWERLZ]

I've found once you get to 28 inches, the velocity gain tapers off to maybe 15 fps per inch. the longer it is.
This could be more caliber specific though
25 fps/ inch is a good realistic number

^^^^^
My buddy decided he would try a 34”barrel on his 338NM to get better velocity than my 338 edge (at 30”), he still couldn’t even match it!

 

[Mike TackleBerry]

I have a 28" RUM that shoots 230 Bergers at 2875 with H1000. Not max. With the 300N it will be higher especially with N570 or similar powder.

You're barely pushing those 230s, Im running Berger 245s over 2880 in a 300 prc with a 28" Bartlein. You could easily get 3100 with the 230s.

 

[Maximus1840]

I'm hitting 2850 using 230 hybrids in a 300 PRC

 

[Orr89rocz]

You're barely pushing those 230s, Im running Berger 245s over 2880 in a 300 prc with a 28" Bartlein. You could easily get 3100 with the 230s.

That sounds very hot, what brass and powder? Custom throat?

 

[ShaunBrady]

If a 300 Norma is your one and only ELR rifle, 30" 1:8 Heavy Varmint contour because that's a standard size barrel brokers stock. You'll go through a few of them on the way to ELR proficiency.

I settle on the velocities that score the best down range. They're generally much lower than the internet. Loading a larger case soft has worked much better for me than smaller cases hot.

 

[Mike TackleBerry]

That sounds very hot, what brass and powder? Custom throat?

Lapua brass, 82,0 Gr VV N568. I'm jumping the .245s .010

 

[tom]

I don't have data for a standard norma, but my improved version has a good node at 3,180 with the 245. That is a 36" 1-8" twist. We have some data, or @GlennK
does, for 30" he could share to see what those 6" are adding...but that was also this improved reamer of Alex's.

Tom

 

[ISS]

Gentlemen,

thanks to all NM shooters. There are five different brands of brass available, which do you recommend?

ISS

 

[Tucker65]

Lapua

 

[ISS]

Looks I need to order Lapua brass. 150 should be plenty.

thanks,

 

[Ledd Slinger]

I also have the Improved version and can push the 230gr Berger to 3200 fps in my 27”, 1 in 10” twist barrel.

Can i hit 3,000 fps with a 245gr? No problem at all.

So if speed is your concern, i would FIRST be looking into building on the Improved chamber version like some of us have.