by Hoot » Thu Dec 25, 2014 8:06 am
Though I never understood why, the Bushmaster mags typically have too strong a spring in them as shipped. In the case of your inexpensive 30 rounders, did you load them all the way to capacity with 450b rounds? Their spring, when loaded to capacity, gets pretty strong as well. As easy as it would be to correct, for all the other refinements in their 450b rifle, you'd think Bushmaster would do a better job with the engineering of their magazines, but then it may just be a result of lack of quality control when being manufactured. I do know that they have changed the design of them several times since 2009. Using just enough spring to do the job would seem like a no-brainer.
No one expects that the first thing they have to do with a newly purchased product is to have to tweak it to get it to work, but that is the case with many new 450b mags. Start with polishing the underside of the lips, where they contact the cartridge using any number of means. Then slide out the floorplate, remove and cut off some of the spring windings at the bottom. If their mags are still shipping with those tine cut-out tabs protruding into the mag about 3/4 of the way down. While you have the spring out for shortening, iron (push) them out with a flat object from the inside. Wipe out any crud, reassemble and have at it. Not as many, but a significant number of them need the lips tweaked to assure the cartridge is aligned optimally, but don't deal with that until you correct the first three items.
Hoot
In Theory, there is no difference between theory and practice. In Practice, there is.