I new to the forum and hope this post is in the right thread.
Anyways i have been having problems with loading EMPTY mags in to my MP-15. My p mags seated fine unloaded with the bolt back or locked. With the Drought of P mags since the school shooting a was able to crab some bushmaster aluminum mags and they wont seat at all with the bolt back or locked. Im new to all this and dont know if its because they are bushmaster mags or what. If i remove the upper from the lower the mags its lock into place just fine. If someone could please help i would appreciate it!

The one thing that comes to mind is that you might try cleaning and lubing the follower in your Bushmaster mags. The only difference I can see between seating empty and loaded is this - the follower pushes up against the bolt catch. When empty, there might be some resistance between the two.

also while the mag is brand new it may have some little rough edges on the followers that keep it from just going right down, Try working the follower up and down a bit and see if that helps.

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Grover Oathkeeper

I tried what you guys mentioned with no luck. All mags are universal right?

Yeah they are supposed to be, it makes me wonder if there is a problem with the last round hold open. have you tried them with a few rounds in them?

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Grover Oathkeeper

Ya i just tried that and the same results. When the upper and lower are separated they lock in just fine.

Supposed to be, but my experience is they are not.

You had me confused. I thought your problem was with empty Bushmaster mags only?

All magazines are not created equal. If the mags were certified to meet a military specification, they should work acceptably in any weapon of that type.

However, there are a slew of companies making magazines, each with their own specifications, which may or may not meet mil-spec standards or the standards of any particular firearms manufacturer. Considering the current panic, I expect there are individual manufactureres who are cleaning out their scrap bins and selling the scrap as good products.

Most firearm companies don't make magazines, they contract that out. OEM mags made to the manufacturers specifications by reputable companies are generally good products and priced accordingly. Even then, you get the occasional oddball that's on one extreme of production tolerances or the other and worn't work in your particular firearm (remember the firearm has a production tolerance too.). This is referred to as "tolerance stack".

Given the current panic over AR mags, I'm sure you can peddle them to someone.

If you can lay one side by side with the Pmag. Look to see where the mag lock hole is. See if it is in the same place as your PMag, it sounds to me like they may be a little lower causeing the magazine to have to be pushed up further into the gun. if it is that way you may be able to take a dremel and fix it, or you may want to do as Mr. Moore said and peddle them off. I would myself see if I could fix it with a file or dremel. But compare and see if that is where your problem lies.

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Grover Oathkeeper

Here is a pic of them side by side

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image.jpg (57.9 KB, 44 views)

Here is another pic of the mag locked into place when the upper and lower are separate. But it looks like i might just have to sell them

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image.jpg (72.2 KB, 37 views)

it really looks like they stick up into the rifle about 1/4" too far, I dont know if you could adjust the latching hole that much or not. if you measure the distance from the top of the mag to the latching holes what do you get? That way you would know how much would have to be trimmed. I have adjusted (trimmed) mags in the past to make them work so it is not something I am totally against. You should see the 15 round mag in my 45acp pistol...LOL

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Grover Oathkeeper

Thanks for the help though, i appreciate it!

A little file job and those mags will work.

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-John

When you seat the mag while the upper and lower are separated, can you put the upper back on the lower or does it catch?

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-Dik