Anyone Ever Lengthen A Magazine To Accomodate Longer Cartridges ???

10 Spot Terminator · March 21, 2008, 10:51 PM

What the hey is up with the 300 Win. Mag ???

Of all the long throated short magazined cartridges I have ran accross so far the 300 Mag may well be the worst. With an average set back of nearly one hunrded thousandths from the lands to accomodate cartridges being able to fit in a magazine I am curious if any one has ever had a magazine "modified" to allow longer than recommended cartridges to fit and allow bullets to be seated out farther to reduce bullet jump to the lands as well as reclaim some of the cartriges powder capacity . Lord knows the 300 Mag comes up way short in both of these catagories. Got a talented smith hid away somewhere who does this kind of thing ? My browning A Bolt had a tack driving round if fed singly but shot like something Fido leaves in the yard when shortened to box length. I want that tack driver back, know what I mean ??
Looking for some insight here folks, Thanks, 10 Spot

Varmitzapper · March 24, 2008, 11:31 AM

I've done a pair of Turk Mausers in .300 WM.
It's not just the bottom metal that gets lengthened.
The steel under the feed ramp needs to be removed also.
BUT!!! on a Mauser you are taking away some strength from behind the lower locking lug. Some people recommend going in both directions to maintain the most material as possable up front.
Don't know what the insides of a A-Bolt looks like.

I don't know if this helps.
I've only got about 90 rounds through this gun so far.
So Far So Good.

Varmitzapper · March 24, 2008, 11:33 AM

I've done a pair of Turk Mausers in .300 WM.
It's not just the bottom metal that gets lengthened.
The steel under the feed ramp needs to be removed also.
BUT!!! on a Mauser you are taking away some strength from behind the lower locking lug. Some people recommend going in both directions to maintain the most material as possable up front.
Don't know what the insides of a A-Bolt looks like.

I don't know if this helps.
I've only got about 90 rounds through this gun so far.
So Far So Good.

Harry Bonar · April 3, 2008, 03:43 PM

Sir:
Yes, we had to (Doc and I) to lengthen the mag on an Enfield ( when we built a 495 A Square) - A P17. and Doc had to lengthen a Mod 70 when rechambering it to 458 Lott.
I share the trepidation in lengthening Mauser mags. and removing metal in that lower locking lug area - I've never done it.
One of the problems with some modern cartridges is with "standard length" mags the bullet is seated below the case neck! I don"t like that either!
I also thoroughly detest the 'short magnums!
The 300 Win. Magnum usually fits the Mauser magazine by filing out a little metal at the rear. But, as you say this leaves your bullet far from the lands.
Until manufacturers start to realize this and mage longer actions we will live with this.Now, A-Square has a paralel throat whisg to a large degree obviates this problem.
One thing you can do is size your fired belted cases is to headspace off the front shoulder with a slight feel when closing the bolt which will tend to "center" the bullet better.
Yes - many times I've wished for a longer mag box and an action where this isn"t a problem.
Harry B.

March 21, 2008, 10:51 PM	#1
10 Spot Terminator Senior Member Join Date: January 3, 2008 Location: Central Oregon Posts: 348	Anyone Ever Lengthen A Magazine To Accomodate Longer Cartridges ??? What the hey is up with the 300 Win. Mag ??? Of all the long throated short magazined cartridges I have ran accross so far the 300 Mag may well be the worst. With an average set back of nearly one hunrded thousandths from the lands to accomodate cartridges being able to fit in a magazine I am curious if any one has ever had a magazine "modified" to allow longer than recommended cartridges to fit and allow bullets to be seated out farther to reduce bullet jump to the lands as well as reclaim some of the cartriges powder capacity . Lord knows the 300 Mag comes up way short in both of these catagories. Got a talented smith hid away somewhere who does this kind of thing ? My browning A Bolt had a tack driving round if fed singly but shot like something Fido leaves in the yard when shortened to box length. I want that tack driver back, know what I mean ?? Looking for some insight here folks, Thanks, 10 Spot Last edited by 10 Spot Terminator; March 21, 2008 at 10:53 PM. Reason: spelink

April 3, 2008, 03:43 PM	#4
Harry Bonar Senior Member Join Date: December 5, 2004 Location: In the Vincent, Ohio general area. Posts: 1,804	magazine Sir: Yes, we had to (Doc and I) to lengthen the mag on an Enfield ( when we built a 495 A Square) - A P17. and Doc had to lengthen a Mod 70 when rechambering it to 458 Lott. I share the trepidation in lengthening Mauser mags. and removing metal in that lower locking lug area - I've never done it. One of the problems with some modern cartridges is with "standard length" mags the bullet is seated below the case neck! I don"t like that either! I also thoroughly detest the 'short magnums! The 300 Win. Magnum usually fits the Mauser magazine by filing out a little metal at the rear. But, as you say this leaves your bullet far from the lands. Until manufacturers start to realize this and mage longer actions we will live with this.Now, A-Square has a paralel throat whisg to a large degree obviates this problem. One thing you can do is size your fired belted cases is to headspace off the front shoulder with a slight feel when closing the bolt which will tend to "center" the bullet better. Yes - many times I've wished for a longer mag box and an action where this isn"t a problem. Harry B.

March 24, 2008, 11:31 AM	#2
Varmitzapper Member Join Date: February 13, 2007 Location: G-Boro NJ Posts: 19	I've done a pair of Turk Mausers in .300 WM. It's not just the bottom metal that gets lengthened. The steel under the feed ramp needs to be removed also. BUT!!! on a Mauser you are taking away some strength from behind the lower locking lug. Some people recommend going in both directions to maintain the most material as possable up front. Don't know what the insides of a A-Bolt looks like. I don't know if this helps. I've only got about 90 rounds through this gun so far. So Far So Good.

March 24, 2008, 11:33 AM	#3
Varmitzapper Member Join Date: February 13, 2007 Location: G-Boro NJ Posts: 19	I've done a pair of Turk Mausers in .300 WM. It's not just the bottom metal that gets lengthened. The steel under the feed ramp needs to be removed also. BUT!!! on a Mauser you are taking away some strength from behind the lower locking lug. Some people recommend going in both directions to maintain the most material as possable up front. Don't know what the insides of a A-Bolt looks like. I don't know if this helps. I've only got about 90 rounds through this gun so far. So Far So Good.