450 Bushmaster question

[nagantguy]

Got an AR Bushmaster this one is finicky as to the magazines it likes- I’ve read many posts about such - it runs top notch with the ASC 5 round mags; any-other magazine even a 20 rounder with the “Bushmaster” follower in it it will not feed or eject reliably. So ASC solves the problem- but they run about $40 a piece - I’ve sold firearms because mags or parts were ridiculously priced- so my question to you guys is what other dedicated 450 magazines do you run that work perfectly? Getting another ASC mag won’t break the bank but I’d like to be able to use some mags already at hand and just interested in what has worked for you- I did read about a fellow polishing the feed lips on a factory Colt 20 rounder dremeling the follower to a near canoe looking thing and gluing a toothpick to either side and than dremeling a notch out of the front of the magazine- to make look similar to the ASC, to my mind that’s more than 40 dollars worth of work considering you’ve ruined a Colt mag, and though hunting isn’t life and death usually this will be a hog/ bear gun in thick river bottoms in MI and TN and KY, don’t want to have my hide hinging on glued tooth picks

[Moleman-]

I've got two AR-Stoner 450BM mags and two USGI (old ones) 20rnd mags with the black molded (not 3d printed) 450BM followers off of ebay. Originally had been using them with a 44 wildcat based off of 30-06/308 ect cases and had slightly bent the lips of them in to better hold the smaller .473" dia cases. They all work fine with 450BM in about 8 different barrels so far using the Tromix type "big bore" barrel extension. Didn't dremel the feed ramp clearance in the front of the mag, so the USGI mags could have the original follower put back in if needed to run 223.

What type of feeding issues are you having?

[Pipefitter]

When I bought my 450BM upper from GLFA in Sparta, MI. They recommended Lancer A5-AWM magazines. Already have the correct follower and are "pinned" (actually a plastic piece in the bottom of the mag) to hold the Michigan DNR required max of 5 rounds.

From what I have read on different sites the 30 round mags dont work well if you try to put more than 8 or 9 rounds of 450BM in them. The 30 round mags are curved to accommodate the taper on the 223/556 cartridge, where the 450 has almost no taper.


Edit: The guys at 450Bushmaster.net have several threads on modifying magazines to work with the 450Bushmaster cartridge.

[Gtek]

There are three here that I put all the parts together, after that I went CRAZY with the magazine thing. I have or have available probably every known AR magazine known to man and it is what it is. I have a plan yet to be completed to "try/fix" the capacity issue for myself but the real problem is the distance between the lips. The presenting .500" body centers between and is way high, not much keeping round in mag. With the .223 body staying under lips and either bolt lug picking right or left, non issue and plays as designed. Bottom of BCG body riding hard on next 450 case until rearward travel of BCG clears and pops 40% of diameter up and out. I am a brass freak and the majority if not all the metal mags scars and gouges the bodies badly on feed. Several found to function okay in the 7-9 round area but polished, tweaked, etc. still damaging and no joy found here. I hunt with mine so the concept of a Zulu charge is not in the equation with me.
Here is what I have been using for several years FLAWLESSLY with mine. Take a 10 round PMAG and break down.
1- Take a very sharp wood chisel and remove the entire center rib from front internal wall top to bottom flush. Must be removed for Gummie tip full length centering.
2- Level follower on mill vise and run a .500" ball mill down center line flush to deck, makes small holes here and there to underside but works fine.
3- Front lip of mag, take something about .475"ish (30-06 case) and wrap crocus and lay in at 30 degrees a radius front lip.
Holds three rounds just fine, four work but really ready to come flying out on its own upward pressure spreading lips. Don't touch spring, cost me a couple until I figured out I should not have touched spring. Hundreds of rounds honest flawlessly, hunting I have one in and two more in pockets. If nine rounds does not produce meat or get me back to boat I am doing something really wrong.

[BD]

I don't know if you can still by the blue plastic single round followers, but I use a variety of standard 20 round AR mags with the blue plastic after market follower installed. All work great. I also use the curved plastic Sig AR mags just as they come for .223 and they work fine as well.

[Earlwb]

I had to file on my metal mags in certain places where the rounds were snagging on the mag lips or edges. But basically, for most of it, I could simply push on the cartridge with my thumb and see where it was catching on the mag edges. Once I got the burrs, and snag points take care of the mags worked fine. I had made up some dummy rounds to use in my rifle to check operation with it too. That let me finalize the magazines then. But the heavy bullets tend to slide out of the cases, so you have to re-seat them in the cases from time to time. But my rifle seems to like the full length AR rifle buttstock, the carbine buttstock seems to let the action work too fast for the big heavy cartridges. Maybe it short strokes a little with the carbine buttstock. But since I use mine for pig hunting a lot, having it work OK with 3 rounds reliably was good enough for me. So I never tried to use higher capacity mags with it.

[nagantguy]

Well I appreciate all the advice, rifle seems to run fine; the new scope will be here soon to accent the MBUS sights- the ASC mags many be a little pricey but figure as this is a hunting rifle 2 should be plenty and they run flawlessly so... guess I answered my own question.

[white eagle]

40 dollars is minimal to get a gun running properly

[gunauthor]

I cheated. I bought a CVA single shot, no magazine feeding issues......

[odfairfaxsub]

I have a glfa and I use the lancers too. They leave a little to desire but never had a feed problem when I got my powder load correct

[Gtek]

The Lancers were about top of the list for function in the metal topped magazines, still was hard on my brass.