This is not mine, nor am I associated with them in any way, but I found this device yesterday on GB: GB LINK

I reached out via their web site rather than GB and bought one that's supposed to arrive later this week.  Am curious to see how well it works - but their videos suggest it works well.


From the ad:


Tired to spend hundreds of dollars for SIG550 551 552 553 magazines ? Ths is the answer.

We have developed a 3d printer adapter which goes inside the gun and lets you use Lancer and Magpul Gen 2 and 3 magazines. How this works :

Basically the set is composed of 3 pieces.

1) The first piece goes into the gun and adapts the gun to Lancer and Magpul magazines (other models could be compatible ut need testing). SImply remove the rear pin, open the gun and insert the magazine slot on the front wall of the magazine.

2) The second piece is a jig,. The jig is marked Lancer and Magpul and must be rested on the top lips of the magazine. The slot in the jig will tell you where to make the appropriate magazine brand you have. This cut is engaged by the Sig rifle latch.

MODIFIED MAGAZINES CAN STILL BE USED IN THE AR15 WITHOUT A PROBLEM. The side of the jig has a bump which will go in the cut and tell you if the cut is deep enough for the latch. In anycase test everytime to make a cut just sufficient to engage the atch and guarantee amagazine inserting without wobble.

3) The 3rd part is an anti slam  sleeve which goes around the body f the MAGPUL magazine ONLY (Lancer does not need it) and prevents over insertion. Again we did not need in our tests but if you like to slam the magazine you could need it as the magpul magazine is way thinner than the Lancer.

With these parts you can convert one gun, One MAGPUL magazine (as there is one sleeve) and ALL the Lancer magazines you want. IF you need more anti slam sleeves for your Magpuls you can buy the aside from us (see othe auction here).

The system works perfectly and even consents bolt hold open like the original. If you want to use original magazines you will have to remove the adapter from inside the gun in 2 minutes (remove rear pin, open gun, reove adapter and close the gun).

If you want to see our SIG 552 SWAT shooting with this adapter lease go here:



To see a practical guide on how to emply these adapters please go here:



Latest news: the adapter is not right for the aluminum lower which has completely different dimensions. We have learned this from a customer who was able to grind the adapter to make it work anyway (the adapter is too thick for the smaller well of the aluminum lower). We can easily make an adapter for an aluminum lower too, but we need to findo one of those and were never able to.

For more information please go www.interfor.us or download the manual please go here:  https://interfor.jimdofree.com/app/download/16401216324/adapter installation guide FLAT.pdf?t=1647207892

Please post your observations once you have received the device(s).  I looked through their website and would like to hear some feedback from customers before I buy one.  Even if it’s not 100% perfect, it could be a great range option to save the wear and tear on those expensive and difficult to find OEM SIG magazines.

The ability to use PMags or Lancers would also help with the 922R parts count.

I was skeptical upon receiving it, but color me impressed; it actually works!  The Lancer mags work better and are easier, as the Pmags were tighter (Gen M2) - but the adapter went on tightly, Lancers fit in fed reliably and bolt hold open on empty worked.

We need to get @Manticore_Arms to buy this from these guys and produce a metal or ABS one.  These guys printed it using PETG, so it's solid, but after only a few uses, I can see some indentations on the front from the receiver closing on it and it may break at some point.

Either way, yep, I give these guys a thumbs up on ingenuity!  Not that the Swiss lowers are common, but I can see any owner of a Swiss lower wanting one or two of these to keep around to allow use of a couple brands of AR mags.  Very cool device to avoid needing to find rare and costly mags.

Those would be nice to have. Someone fire up their printer. I bet the MagPul Emags would be the hot ticket.

I don’t mind the price of the 55x mags, the availability is my issue.

Anyone else try these?  They work well.  I modified all my Lancer mags to use - haven't tried Pmags yet.

I thought the video indicated that you don't have to modify the Lancer magazines?

They need a small slot cut in the back for the Swiss style lower mag catch (on the back of the mag).  Takes about 30 seconds with a small file per mag and they include a jig for Lancer mags so you know where to make the "notch".

They work pretty well,  won’t last long as noted.  They are printed in black and the jig is yellow.  

Pmag was loose side to side.

To me, very crafty but seems more useful north of the border due to the pinning of mags.

Kind of like modifying your Ferrari to run on biodiesel.

Hats off and more power to the entripinuteral inventor.

So I did notice at the range the previous weekend that some rounds were trying to feed too high and hit the nose above the barrel.  I don't know if that was due to the mag being seated a bit too high or what.  Unfortunately, I only brought one of the Lancer mags and didn't differentiate the mags from previous uses.  I'll have to see if it was just that mag or something else.

Anyone else try this device yet?

I have some of the earlier ones from the outfit in Canada.  I wouldn't spend money with interfor stuff especially if you're noting it's feeding high.  Quick way to grenade your rifle due to pushback on the bullet and detonation (same reason not to use modified Galil mags on Valmet)

I have.  I was excited for this product, but three malfunctions in less than 50 rounds (used three different Lancer mags), and I took it out.  Looks like I'll be sticking with original mags...

a low feed can cause bullet set-back and if you don't notice it and it's chambered and fired, can be a potentially deadly overpressure.

With all non-factory mags, it's helpful to test feeding with some snap-caps and check feed angle and position.

The circle of Swiss Madness =

-Get a Sig 556
-Get a 550 lower to replace despicable US style M16 magazine well
-Get a mag adapter to use M16 mags

I love my 556 SBR, but really like the original contours of the original series.

Lol!  Pretty much...