AI detach magazine for 300 WMag /458WMag

H

hemiford

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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.
 
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.

www.milehighshooting.com

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

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

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ShtrRdy said:
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.

www.milehighshooting.com

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

AI 0479: AICS .300WM/ AW .300 Win Mag (5 Round)
www.milehighshooting.com www.milehighshooting.com
Click to expand...
HHHHMMMMMMMMMMMMMMMMMMM................................................great.

Many Thanks ShtrRdy !
 
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.
 
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.
 
ARlife4me said:
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.
Click to expand...
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.
 
if the mag is made the same (ribbed) then no. i'll check my 338lm mag (cip also). unfortunately, it's a no-go also (ribbed).
 
Mill out the front ribs on a CIP length .300 Win mag magazine and it will work for you. That's what I do to run Ultra Mag cases in them. In the photo's you can see the front rib in the mag has been milled out. There may be a company selling them like this by now.


IMG_1453.jpeg


IMG_1452.jpeg
 

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