I bought a Bulgarian Waffle mag from K-var and it does not fit into my SAR-1.  It will fit when you initially put it into the magwell, but when you go to rock it back to lock it in place it won't even get halfway in.  Has anyone else had this issue?  What did you do to correct this?  I will assume I'll have to grind some to get it to fit, but is this usually a problem?  I have 9 other magazines(not waffles) that all fit with no problems.  

Funny, my buddy just had the same problem. DO NOT grind on the mags...not that you would, but the problem is this: Take the empty rifle and look into the mag well. Look to the rear (mag release side)inside, you will see a cylindrical bar that goes from one side of the receiver to the other, for strength I guess, rivited to either side. That is what the waffle mags hang on...and only in the SAR-1. His SAM7 and my Vepr have this piece as well, but it is further back out of the way allowing the waffles to seat in the well. The waffles work in the Saigas fine too, just for some reason, the Romanian AK's have it just enough in the way for the larger waffle mags to hit on.
Now, I do not recommend this at all, but he decided to cut that little rod of steel out, and the waffles now fit the sar1. What that will do to the strength of the receiver has yet to be seen, but he did shoot it and it worked fine. Perhaps it could be moved to another position, but why bother since all the other mags work fine. Hell, I will buy your waffles...LOL!

I definetely don't want to cut anything out of the gun that is more than likely there for a reason.  I'm gonna check that out and see if that's what it is and if so I'll be looking to trade for some different mags.

I filed some of the polymer off the front lug.Works fine now. (MAK 90)

WELL SHIT!!! Nice to hear this now AFTER I ordered those mags from KVar.  Given the choice between altering the firearm or the mag to make them work, I'd alter the mag any way possible without compromising its integrity.

It's no big deal. Just take some sanding paper and lightly round out the back upper edge of the mag. That's all you need to do. I did it to several of my waffle mags when they wouldn't fit in my AK. Don't modify the AK or mess with the mag's locking lip.

They fit in both of my SAR1's no problem, over 30 waffle mags.

I bought nine of them from K-Var. They all fit my SAR1 just fine.

Ok, my waffles fit my SAR1 fine. I had my waffles before my SAR1 arrived, so now I think I want more  waffle mags. Verrry nice mags. Nice look.

This waffle fit thing must be on older SAR 1's, seems like the few posts I have seen on this here and there go along with this. Wish we could get some kind of date-to-mag fit comparison going. LOL, I told my buddy about removing a tad on the mag, so now he regrets chopping on the gun. Oh well, they fit my Vepr fine.

Had a problem with two out of four fitting in my SSR-85C.  Sandpapered the back of them a tad and fixed them right up.

Thanks for the fix guys!  This place is the best.

All mine fit in my '03 sar (knock on wood, I just ordered more).

I had the same fit problem and solution on my Maadi ARM.