300NM or 7-300NM, standard or improved 30*?

18Echo

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So I have two Long Action Impacts with magnum BF, and two additional bolts one standard and one Lapua. The Split rail is going going to be a 30-06 / 300 WM switch barrel. The full rail is going to be a 300PRC and some form of Norma Magnum.

I'm debating 300 Norma vs 7-300 Norma, and whichever one I decide on should I go standard case or Improve it 30 degrees? I'm assuming my 338 Norma dies will work with either flavor in a standard chamber and that I just need to pick the right bushing for the sizer and correct stem for the seater? For an improved version I suppose I would send some fired cases to Neil Jones for a FL sizer and seater.

What do you think the real world velocity increase from a standard to improved chamber will be for both? Is an improved version worth the extra hassle over a standard version when it comes to bang/flopping an animal?



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Huskydriver

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300 Norma mag uses a 338 Lapua bolt face
300prc uses .532 bolt face
 

Bradu

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Standard version is pretty tough to beat. You will gain 100-150 fps with the improved but the wait time for dies to be made was what kept me from going that route. I have a 7-300 norma and run 195's at 3150. I pushed them to almost 3300 fps with minimal signs of pressure. You need the vld seating stem and the correct bushings for the 7mm version. I neck turned then necked down in 3 steps using bushing dies.
 

MountainHunter

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For reference my standard 300 Norma pushes 245 EOL’s at 2925 with 86.5 grains of N570 in a 24” benchmark carbon on a lone peak ti fuzion. I tested up to 2975 without pressure.
 

kthomas

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I have a .300NM.

If I was to do it again, I would do a .300NMI (something like a 35* shoulder).

My current .300NM barrel (29") is pretty slow, running 230 hybrids at 2950 fps before finding pressure. For the amount of powder behind that 230, I certainly expected more velocity. An improved version would help with that ballistic efficiency, while reducing the need for trimming.
 
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18Echo

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I have a .300NM.

If I was to do it again, I would do a .300NMI (something like a 35* shoulder).

My current .300NM barrel (29") is pretty slow, running 230 hybrids at 2950 fps before finding pressure. For the amount of powder behind that 230, I certainly expected more velocity. An improved version would help with that ballistic efficiency, while reducing the need for trimming.
That does seem pretty slow for a barrel that long, what powder are you using?
 

kthomas

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That does seem pretty slow for a barrel that long, what powder are you using?

Retumbo.

Could be a slow barrel. Some barrels are just faster or slower than others. This specific one is a benchmark.

I have a Hawkhill barrel to put on after I burn this one out, perhaps that one will be faster.
 
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MOUNTIC

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    300 NM. 3005fps with Retumbo for me out of a 27" tube with the 230 Atips. 85.5 of retumbo in that load with Peterson Brass.

    300 PRC and 300 Norma are pretty close and almost redundant on the same rifle. I prefer the Norma if I could only pick one between those two. If you want to have some variety, go with the 7-300 Norma as you have 3 of the 30 cals already picked out. That 7-300norma is a bad machine with some of the new 7mm pill offerings.
     
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    Huskydriver

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    I also didn't get much better with retumbo with my 27" 300 Norma and concluded the juice wasn't worth the squeeze compared to 300 prc.
     
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    18Echo

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    I suppose that is a good point, reference the 30 cals, and finding 215’s or 230’s seems to be pretty tough lately. 195EOL’s are pretty scarce too. I suppose I could put myself on a bunch of notifications and then just watch out for them while I get a reamer made by JGS for a 7-300 Norma improved throated for 195’s at Mag length, I’m assuming an 8 twist would work, Fireform some brass and then send some cases to Neil Jones for a full length sizer.
     

    dgheriani

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    I think the 220gr LRHTs are the perfect compromise in a .300 NM. 215 speeds and 230 BC. I push them at 3190 out of a 29.5" Krieger with 90.4gr of N570. Thing is a laser beam. I'll echo that having a 300NM and 300PRC on the same action seems kinda redundant. I'd go 300NM over PRC but if you're deadset on the PRC for whatever reason then I'd either do a 7-300NM or a 338NM.
     

    Hennig

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    Am I the only one looking at the plan and wondering why youre chambering so many similar performing .30s? 300NM/300PRC/300WM.

    I vote 7-300NM for the 4th barrel just for a bit of variety.
     
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    18Echo

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    Am I the only one looking at the plan and wondering why youre chambering so many similar performing .30s? 300NM/300PRC/300WM.

    I vote 7-300NM for the 4th barrel just for a bit of variety.
    The 30-06 and 300WM is because you can always find it at a Walmart or an ace hardware etc. when times get lean.

    Love 30’s , but like the 7’s too.
     

    18Echo

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    Okay, after some thought I’m going to nix the 30-06 and go with a 6.5 x284 Norma and Berger 140’s or the 156 EOL.