300 WM

Wis65x55

Handloader
Jul 31, 2011
329
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I have a 300 WM Hells Canyon long range. When i went to check chamber dimensions I discovered that distance to lands is 3.545max COAL. I am using a 200gr Partition bullet. Due to the additional length how much is this likely to affect pressure? Rifle twist rate is 1:8 with a 26"barrel
 
Longer necks lower pressure.

As long as you stay off the lands, you’ll be in pressure spec. What’s the longest COAL your magazine can handle?

Pressure gets dicey on short chambers and necks that tend to be saami or less.

Weatherby mags typically have long throats.

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mjcmichigan":2ke34cc3 said:
Longer necks lower pressure.

As long as you stay off the lands, you’ll be in pressure spec. What’s the longest COAL your magazine can handle?

Pressure gets dicey on short chambers and necks that tend to be saami or less.

Weatherby mags typically have long throats.

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Sound advice given.
 
I think you're in good shape . load the bullet with a 0.015 - 0.020 jump to start with . this length should feed out of the magazine . start at min powder charge and work up . I think you should find something decent .
 
jimbires":2tx79olz said:
I think you're in good shape . load the bullet with a 0.015 - 0.020 jump to start with . this length should feed out of the magazine . start at min powder charge and work up . I think you should find something decent .
I do like Jim. Be glad your magazine matches your guns throat.... doesn’t happen that often...


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If i don't like what I see I also have RL22, 26, IMR 7828 to play with.
 
72 grs of R22 with 200 gr AB gave me 2900 FPS and cleanly dispatched my once in a lifetime ID bull moose.
24” barrel and plenty of recoil. 3.510 oal; work up it’s a stout load!
 
It’s probably throated for a VLD of some sort…Berger or ELD maybe. Those take up more length.
 
I think it’s a standard throat. Most standard SAAMI 300 Wins will take a sharp nosed bullet much further out than what the book says they should be loaded. I actually like the standard throat as it works great with a 3.6” magazine box with sharper ELD and Such.

Like Jim said, seated out like that, but off the lands 10-20 will lower pressure to a certain extent since you are giving the combustion chamber more room. I wouldn’t be surprised to need a bit more than the book calls for to reach book speeds and that ain’t a bad thing.

Browning did good giving it an 8 twist and a longer magazine. That makes the 300 Win an animal.
 
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