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Location: Rio Rancho, New Mexico
Joined: 06/17/2007
Posts: 5
300 Win Mag. O.A.L.

Have shot a 300 Win Mag for years. Used Nosler's and Swift A-Frames. Decided to try Accubonds (165grs.) this year. I have always loaded my bullets pretty close to factor specs. for overall length. Going to try to load some closer to the riflings in search of better accuracy. My chamber measures in at 3.603. I am reloading at 3.574. Anyone out there have any suggestions?

Don Fischer's picture
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Location: Antelope, Ore
Joined: 03/24/2005
Posts: 3173
300 Win Mag. O.A.L.

Welcome to the site. Probably would have got a quicked response on the reloading forum. Been a lot of years since I've reloaded a 300 mag and I've never owned one. a premium bullet then was the Nosler Partition or the origional Barnes bullets.

Some bullets have a preference for seating depth and some seem to shoot well just by showing up. You need to experiment a bit. I'd start just off the lands and fool with it a bit.

Let us know what happens. Maybe 91xlt will move it for you.

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Joined: 12/03/2005
Posts: 1691
300 Win Mag. O.A.L.

Welcome also:
Other than what Don said, I would always start from scratch every time you decide to change your powder type. The distance from lands/groves that the bullets seats increases pressures. >.060 from lands with a maximum charge of H4831 may be fine but the same distance with a max load of IMR 3031 would be pushing the extreme button.
I'd try to get them around .010 distance if it was me.

bitmasher's picture
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Location: Colorado
Joined: 02/27/2002
Posts: 2973
300 Win Mag. O.A.L.

Its difficult to say, because the ogive is different on each bullet. Like the others have suggested, I would start fresh with finding the o.a.l that touches the lands then back off 6-9 hundreds and see how it papers, then start moving inward. Strangely some bullet, powder, chamber combinations don't like to be tight on the lands, so moving in may not help.

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Location: Rio Rancho, New Mexico
Joined: 06/17/2007
Posts: 5
300 Win Mag. O.A.L.

Thanks guys. Went out and shot some at, 3.574" (.029 off)). I got a 3-shot group that measured 3/4". I really put a lot of effort into this gun, (trigger,barrel break-in,David Tubb's bore polish process, cases weighed,necks turned, weighed bullets, and weighed charges. I know it's a factory barrel and 3/4" is very good for hunting purposes. I think I will also try .006-.010 off as you guys suggested. Thanks for the re-inforcement on the O.A.L's. Almost everything you read says 3.340" for the 300 and I guess I just got to thinking that anymore would prove disastrous in more ways than one