AI detach magazine for 300 WMag /458WMag

[hemiford]

I'd like to use these AI mags in my next build. They make a 5-round magazine in CIP length (3.850 internal)
for the 300 Win Mag.

My cartridge is going to be 458 Win, not 300 Win. I called AI and asked if the feed lips on this particular magazine
would also work with the 458 and they kind of sidestepped the question and didn't really answer. I realize that it
must be very uncommon to find folks who have loaded 458 Win in a detachable magazine !

So here's my question. Does anyone here use the CIP magazine in 300 Win ?
Can you eyeball it and guess if the feed lips would feed a 458 ?

Now it's true that SAAMI 300WM is only 3.34" , likewise with the 458, so maybe the CIP length magazine will be fine, I don't know.

 

[ShtrRdy]

If I recall correctly, the AICS magazine for the 300 Win Mag has a rib feature pressed inward on each side of the mag body to prevent the loaded cartridge from sliding forward by blocking the movement at the shoulder. The 458 Win Mag cartridge may not fit because of this.

Accuracy International 0479: AICS/AW .300 Win Magazine (5 Round)

AI 0479: AICS .300WM/ AW .300 Win Mag (5 Round)

www.milehighshooting.com

 

[hemiford]

If I recall correctly, the AICS magazine for the 300 Win Mag has a rib feature pressed inward on each side of the mag body to prevent the loaded cartridge from sliding forward by blocking the movement at the shoulder. The 458 Win Mag cartridge may not fit because of this.

Accuracy International 0479: AICS/AW .300 Win Magazine (5 Round)

AI 0479: AICS .300WM/ AW .300 Win Mag (5 Round)

www.milehighshooting.com

HHHHMMMMMMMMMMMMMMMMMMM................................................great.

Many Thanks ShtrRdy !

 

[ARlife4me]

with the 300 being shorter it might still work? measure the case diameter at the 2.196" mark from the base. if it's near .489" it could still work. i can also check feedlip suggested measurements and post back.

 

[ARlife4me]

btw, i have the same mags as you posted (cip 3.850").

 

[ARlife4me]

also the 3.850" might just be external instead?

 

[ARlife4me]

internal coal i'm getting is 3.765" and 6 rounds. post #2 nailed it. the ribs hold the case to the rear from the neck. 458wm is a no-go in 338wm and down. 350rm is the largest cartridge that'll work as rum's are a no-go also.

 

[hemiford]

internal coal i'm getting is 3.765" and 6 rounds. post #2 nailed it. the ribs hold the case to the rear from the neck. 458wm is a no-go in 338wm and down. 350rm is the largest cartridge that'll work as rum's are a no-go also.

Thanks ARlife,
I guess nothing is simple. AICS says the outside length is 4.01, inside CIP is 3.85, actual room for the cartridge is 3.75.
Which would still be fine if the 458 bullet would fit.
They do make a CIP RUM magazine, but that might not help me either.