300 Norma mag improved freebore specs

Earl Fouraker

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I’m trying to spec out a reamer for a 300 Norma mag improved. I was curious as to what freebore everyone is running. I’m going to spec mine for shooting the 245 Berger’s and 250 a-tips. I don’t have any 250s on hand yet due to the current bullet supply issue.

A .235 freebore works with the 215s, but without measurements for the 250s I’m just guessing.

Thanks
 

highdrum

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I’m trying to spec out a reamer for a 300 Norma mag improved. I was curious as to what freebore everyone is running. I’m going to spec mine for shooting the 245 Berger’s and 250 a-tips. I don’t have any 250s on hand yet due to the current bullet supply issue.

A .235 freebore works with the 215s, but without measurements for the 250s I’m just guessing.

Thanks
You're kinda defeating the purpose of the norma by throating for 245s. You'll be long enough that you won't be able to use dbm or standard 3.85" wyatt's box. You'll need a 4" cfe9 to load close to lands. At that point, use a lapua or rum. As they have more capacity to push the 245/250.
 

Earl Fouraker

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The reason I chose the Norma mag is to be able to keep it a repeater. The cfe-9 box is what I intend on using. I know I couldn’t achieve that with the lapua and definitely not the Rum if throated properly. Im hopeful that 3000fps with the 250 Atip in the improved version is obtainable with n570 and lapua brass.
 

highdrum

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The reason I chose the Norma mag is to be able to keep it a repeater. The cfe-9 box is what I intend on using. I know I couldn’t achieve that with the lapua and definitely not the Rum if throated properly. Im hopeful that 3000fps with the 250 Atip in the improved version is obtainable with n570 and lapua brass.
Barrel length? I used N570 in my 300nmi with 245s, granted I'm at 250k freebore. I had a nice wide node @ 2990-3010 fps. But its on the WARM side lol. This is a 26" proof 9tw. Pierce 33° chamber. Also on a side note......250s for hunting? I know Broz killed a handful of elk with them from a 300 lapua improved. 3200fps or some craziness. He went away from them after inconsistent expansion on animals at various ranges, from mid/long to long.
 

Earl Fouraker

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Planning on using a 1:8 brux 28”. I doubt the rifle will see any elk. If so I’ll prob opt for the 230 or 245 Berger. Seems they have a proven track record.

Curious what your coal is with the 245s and the .250 throat length. 3000 FPS with a 245 in a 26” barrel is impressive.
 

highdrum

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Location
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Planning on using a 1:8 brux 28”. I doubt the rifle will see any elk. If so I’ll prob opt for the 230 or 245 Berger. Seems they have a proven track record.

Curious what your coal is with the 245s and the .250 throat length. 3000 FPS with a 245 in a 26” barrel is impressive.
It barely fit in my cfe12 box, so roughly 3.82" I was seated 45k off lands, I just shot a 400y ladder with them for testing last summer. 88.5-89.5 was 2990-3010 and held 1.5" of vertical. 45k off was recommended from a fellow shooter who's quite accomplished, he found it worked well in his 300nmi, that's a Wheeler build.
 
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