AR 450 Bushmaster Mag Issues

[missionary5155]

Good evening
We have a good load that functions our 450 Bushy. But so far every mag we have tried with more that 2 rounds loaded will stove pipe the slug up at the chamber.
With 2 rounds the first loads, fires, ejects and chambers that second round with no issues.
Have tried different mags, bullet guides (the lifter in the mag), military, civilian.......
So what mag works ??
Thank you for any enlightenment you can pass on.
Mike in ILL-Nois till mid November.

[Dutchninja]

All standard mag springs?

The tip of the bullet gets jammed at / before the chamber at 12 o clock?

Or is it jammed at the mag / feed ram?

[cwlongshot]

I found some followers SUK!! Also dremil the front of the mag so case mouth passes ove without contact.

CW

[missionary5155]

Thank you cw...
The present follower we are "using" is a simple rounded channel centered in the magazine.
I have been searching for mags on internet and saw one for sale that had the front side of the mag lowered.
That could well be the issue.

Dutch.. Yes the round gets bullet turned up near vertical with the bullet tip before the chamber at 12 oclock.

[missionary5155]

Found a close-up of a Duramag front side. That gives a very good view of the cutting I need to work at.

[lawdog941]

Duramags work the best for me. Problem is getting them while in stock. Modifying looks like the most logical approach.

[ohen cepel]

I had to buy new followers, from Tromix maybe? Quality item, not a 3d printed product.

Then, had to Dremel down the front of the mag.

Took me a lot of effort/time to get my 450 going. NOT as easy as the makers say and that line about using "std" mags is totally wrong!

You'll get it figured out, just takes some trial and error.

[missionary5155]

Good morning
Do the Duramags hold bolt open after last round ?
Going to the bench and do some Dremel work on two older AR mags.

[cwlongshot]

Mine do. Yours should.

CW

[missionary5155]

As of yet I do not have any.

[lawdog941]

As long as your springs in your old AR mags are good, and are able to cut out the nose portion of them, they should work out fine. Give them a try and let us know.

[Dutchninja]

Try wolf extra power springs, when the bolts comming forward the back end is driven down a bit causing the round to hit at 12, the extra power springs puts more upward force on the round against the feed lips keeping it more level as the bolt sends it forward,

When I had started loading 300 black out sub Sonics 240 cast PC’ed lead, the nose and OAL made them very nose heavy. I thought it was wrong load, tried different powder all types of mags, and the did some slow motion filming with my phone and could see the back end getting jamed down, try the more power springs, and off to the races. I have dedicated mags for 300 subs and heavy heavy socom rounds.

It might help, not sure but their cheap you get three, and worth a shot. Hope you get it figured out.

[Dutchninja]

Also rifle carbine or pistol lenght gas system?

[missionary5155]

Howdy Dutch and thank you for the info !
It has a carbine length gas tube.
Heavier Mag springs... I would not have thought of that one.
Hopefully the rain stops sometime tomorrow and I can give the "groove cut" mag a try. Ran 7 dummy rounds through it after the dremel time and all cycled perfect. But I also understand that is nothing compared to the cycle speed upon firing.
10 rounds should give me a good idea if more needs to be done.

[gumbo333]

When I had a 450 Bushy I used a 5 round mag I got at Midway for a 500 Beowulf. It worked great, no problems, no adjustments. A 16" carbine.

[missionary5155]

The "cut" Mag worked great ! No standing up followup rounds. Good ejection and bolt pushed next round straight into chamber.

But now an issue I have known existed is causing some rounds to fail to fully chamber.
Been using Buffalo Rifle for load development with a 250 grain. Well the unburned "mummies" have always been there and now for sure they are an Issue ! 4 out of 10 rounds failed to fully chamber and the fired brass showed the "dents" near the mouth where the "mummy" was jammed into the brass. Forward assist was needed to fully seat.
As long as I was chamber brushing every two rounds no issues over the last two weeks but now it is time to look at another powder.
So what would you suggest with a 250 grainer ?

[cwlongshot]

AA#9

Is all I use for jacketed.

CW

[lawdog941]

Lil Gun works for me. No problems.

[cwlongshot]

Lil gun burns super hot in a M$R. Plus pressure spikes are probable.

CW

[lawdog941]

I haven't had any problems yet. Although I don't run and gun it. It's a hunting rifle, max 2 shots. Lil Gun is a hot burner, but common sense use, it works.