I have a left-handed Model 70 in 300 Win. that I was considering re-barreling to 458 Win.

While using a dummy 458 round, I noticed the case head would not fully engage into the bolt face. This stops the CRF function of the action. Will a stronger magazine spring fix this? If not, what is the fix.

Thanks,

Roger QSL

How far into the feed does it jam?

The tension from the magazine spring is needed to hold the cartridge in position so that the bolt can strip it from the magazine. It's a combination of the feed ramp, the shape of the follower and extractor that's responsible for putting the cartridge into the bolts face.

The larger diameter of the 458 makes the approach angle much steeper as the cartridge starts up the ramp potentially placing unnecessary drag of the case head on the bolts face. If the relief cut at the bottom of the extractor isn't enough to allow for the increased angle, it will jam as the round try's to come up.

Not having the actual gun in hand, my initial "guess" would be that you try to change the angle at the bottom of the extractor to allow for a much steeper angled feed. First feed the 300 and watch how the cartridge slides into position and then the 458 to see the difference. You should be able to spot the area of the extractor that needs a slight adjusment. FWIW, Changing that angle on the extractor ever so slightly isn't going to hamper feeding in the least. If nothing else, it can increase reliability. You may want to have an experienced gunsmith make the necessary adjustments for you.

G Malborg,

It doesn't jam.
It acts more like a push feed. Sort of positions the case head more then half way onto the bolt face. Not enough to grab the case as a CRF should but like a push feed action.
Will have to wait as to trying a dummy 300 Win. as I don't have the dies to make up a 300 dummy. Don't want to use live ammo in the neighborhhood.

Thanks for your input.

Roger QSL

quote:

Originally posted by Roger:

Will have to wait as to trying a dummy 300 Win. as I don't have the dies to make up a 300 dummy. Don't want to use live ammo in the neighborhhood.

Close the bolt and place the safety in the center position. Remove the bolt, depress the little catch on the side of the shroud and unscrew and remove the firing pin. Now you can safely feed live ammo.