I am developing a load for my 300 Win mag using a 180 gr nosler partition. The rifle is an a-bolt with detachable mag which limits seating depth to the standard 3.340". Anything longer than this simply will not feed. In their 5th ed. manual, Nosler states, "to seat any of our 180 gr. spitzer style bullets to 3.340" is impractical, as the bullet will be seated past the end of the ogive curve and risk falling into the case." My question is 1.) Has anyone seated a 180 gr. nosler bullet(partition, accubond, bt, etc. to 3.340" in the 300 win mag and if so 2.) Were there problems resulting from insufficient neck tension? I am worried about the rounds in the magazine having the bullet driven into the case, resulting in dangerously high pressure. Thanks.

Sounds like you need to modify your A-bolt in the manner it should have come from the factory in the first place.

The A-bolt long actions are all the same length, and long enough to accomodate the 3.6" magazine that comes with the "long magnum" calibers. I think that it is as simple as obtaining a longer magazine for your A-bolt, however, it could require some modification to the bolt stop, etc.

The .300 Winchester badly needs the full length magazine to load and function as it should.

I'm with Stonecreek on needing to do something like taking it to a gunsmith and see if he can install a regular floor plate and spring and get rid of the detachable magazine.

A short term partial solution would be to use the Nosler Partition Protected Point bullet rather than the Spire Point. The Protected Point bullet's ogive is much farther forward. Also something like a round point bullet. Your ballistics would suffer but some of those round points can be very accurate and terminal performance can be excellent.

Usually seating the bullets deeper reduces pressure and creating an overpressure situation should not be a concern. Be sure and start lower and work up looking for pressure signs.

JMHO

Hey Woods,
I had considered using the protected point partion, but the low bc turned me away(something like .373 I think). I know it won't make much of a difference at "normal" ranges, but at longer ranges I am not willing to give up the loss of trajectory and energy. Hey Stonecreek, is the 3.6" mag you are talking about for the 375 h&h or 300 weatherby?

If I remember correctly, the A-bolt uses an internally detachable magazine (it pops loose from the floorplate). You can get one made for any of the long series of cartridges (7mm STW, .300 WBY, .375 H & H, etc) and it may fit in your gun as is, but can surely be made to fit with minor gunsmithing.