450 Bushmaster Mag Mods

[mattri]

To clarify- you don't modify the spring at all correct?

[Underhammer]

"To clarify- you don't modify the spring at all correct?"

Punched a 1/8" hole thru it for a small screw to hold it from sliding.

[GaCop]

Opened up the feed lips but, with two in the mag, top round feed slick, last round still hangs up on case mouth. Still a work in progress...….

[mattri]

I'm not having any luck either. Tried the above mods and also tried modding the original 223 mag like this:

https://www.youtube.com/watch?v=x2jJhj5Zd10

So far no joy.

Would a WSM mag be useful?

[GaCop]

I'm not having any luck either. Tried the above mods and also tried modding the original 223 mag like this:

https://www.youtube.com/watch?v=x2jJhj5Zd10

So far no joy.

Would a WSM mag be useful? Don't know about a WSM mag but I got a 22-250 mag off of eBay but it needs mods too and will not feed blunt bullets. I notice, all bullets clear the front of the mag box, it's the mouth of the case that hangs up. Gotta play with feed lips more and mod the follower/spring.

[mattri]

Thanks for the information re the 22-250 mags. Do they need the spacer added at the rear of the mag as well?

[Underhammer]

Thanks for the information re the 22-250 mags. Do they need the spacer added at the rear of the mag as well?

Unless you have the original 22-250 mag that has the block in it, you need to add one.

That move the shells forward, this causes nose diving!

Now you need to move the spring forward. Maybe even give it a stretch.

Then, you may need to widen the feed lips.

WSM mags need the feed lips closed up a bit, so that the cases don't push up and out!

Or, just use a 223 Mag.

https://www.youtube.com/watch?v=x2jJhj5Zd10&feature=youtu.be

[GaCop]

Thanks for the information re the 22-250 mags. Do they need the spacer added at the rear of the mag as well? It just might. I tried a few of my 300 grain XTP Mags and the mouth of the case hung up just like my 243 mag did. I have yet to start playing with adjustments.

I did find that Hornady 350 grain jacketed round nose seem to feed will from my modified 243 magazine after I first crimped the round with the Lee collet crimp die and then my RCBS 45 ACP taper crimp die . The Hornady 350 grain were originally .458 diameter so I ran them thru my .454 sizer then a .452, they came out great. Did the same thing with Speer 400 grain JFPs.

[mattri]

Thanks for the replies. May try working with the 223 mag some more, it seems close.

[Underhammer]

Thanks for the replies. May try working with the 223 mag some more, it seems close.

It looks like a lot of spreading, go slow, or it could end up quite ugly looking!

Have you tried the spring and follower out of the 223 in the 308 mag? [with block]

[mattri]

Wonder how a 350 Legend mag would work..

[mattri]

Success!

The WSM mag works! I bent the feed lips in just a touch and used the spring from the 223 mag, moving it to the front of the mag and using a little JB weld to hold it in place.

My handloads with 300gr XTPs feed and I now have an honest 3 round mag.

The 400gr cast bullets have such a huge meplat that I don't know if they would ever feed reliably in any mag, factory or not.

Will post pics soon.

Still curious re a 350 Legend mag...

[Underhammer]

Great, glad that you have one that works!

Did you use a rear spacer?

[GaCop]

Success!

The WSM mag works! I bent the feed lips in just a touch and used the spring from the 223 mag, moving it to the front of the mag and using a little JB weld to hold it in place.

My handloads with 300gr XTPs feed and I now have an honest 3 round mag.

The 400gr cast bullets have such a huge meplat that I don't know if they would ever feed reliably in any mag, factory or not.

Will post pics soon.

Still curious re a 350 Legend mag... Good to know, thanks! My resized 45-70s, RNFP, will feed from my modified 243 magazine. I have them seated out quite far and that seems to help feeding. I'm only about .020" OTL. The first two feed beautifully but the last want's to hang up just a bit at the case mouth.