In my experience...
The only function of the bend on the front is as a follower stop on an empty unseated magazine.
The only exception is to also assist in nose dive jams ... Joe

Thank You veterans!

Grabagun shows part number 17696 for $18.35 but their prices can change daily.

That 6 hole mag pictured must be an old photo...Gen1 or maybe preproduction?

At least vs Gen2 mag:
Thin base plate, follower shape different on top, and no follower stop bend on the front of the body.

Joe

https://grabagun.com/remington-r51-7rd-magazine-stainless1232.html

Welcome... Interested in your input too!... Joe

Two different operations...
Vise was used to slightly increase the width of the mag body.
Pliers used to adjust front of feed lips out until they are parallel... Joe

*Edited to add pics*
Bench vice is not a precision tool  so your experience may vary... Protect mag body. I used aluminum in jaws.
Pressure from vice should cause sides to bulge out. Measure several places across body and adjust as required.

Used tooth of pliers to hook lip and leverage out... About .005-.010 per side as required.

Quote from: David on April 16, 2018, 07:12:43 PM

I note you opened the body of the magazine by .010.  What is your technique for doing that (I am envisioning compressing the front and back in a vice).

Yes! Good guess!... Tried prying and wedges etc inside. Very inconsistent. Careful compressing in a vise did it without any unwanted distortion.
Disassemble and the body fits perfect across a four inch jaw. Goes pretty quick once you figure out the "spring back"... Joe

Range report follow up to my previous post.
350 rds since the above mods and all six mags function perfect with a variety of ammo.
I have settled on these three mods for all six mags: open feed lips until parallel, open body until no drag on brass, and trim follower stop bend... I have not modified the follower or spring. Works fine with full mag, partial mag or 7+1... Yes 7+1 requires extra effort to seat the mag but that is not how I typically load this pistol.
I trimmed the bend about 45 degrees angle. This removes the place where most nose dives grab but leaves just enough bend to act as a follower stop. Can be done with a bench grinder then small files and emery cloth to clean up... I'll add that this mod may not be needed as I think one or both of the other mods are more likely to help with feed issues.
Pictures from before all mags were trimmed... Joe

Interesting history... I was told an old school way to safely dispose of unwanted ammo was to soak in oil. Kills the primer and probably not good for the powder either. Don't know if this applies to modern ammo... I have some Federal +P and Speer ammo that functions fine in unmodified mags. Some folks here say their R51 eats everything fed. Mine is picky. Seems to like hotter ammo... Joe

funflyer, that Numrich pin looks like it!... Joe

Had the breech block apart a few weeks ago to clean. I bent a brass punch trying to drive the retainer out. Had to use steel.
The firing pin retainer is stepped not tapered.
It will drop in the chamfer side to hold the firing pin and spring, and must be driven until flush from there.
I didn't measure it... Joe

** Edited **

I have two types of IMI factory ammo that constantly nose dive or misfeed only in the R51.
R51 owners manual says to lightly oil everything including the mags.

So for troubleshooting I used an unmodified mag. Disassembled, cleaned, lightly oiled entire inside surface. Follower, lips, ridges... Everything.
Then lightly oiled seven rounds of the IMI ammo.
The oiled ammo loaded and unloaded from the mag by hand much easier than normal. Also fed and cycled flawless by hand though the R51. Everything worked perfect with reduced friction: brass to feed lips, brass to mag ridge, and brass to brass...
I did not live fire this setup. Lube can damage ammo and should not be necessary.

Then looking at the empty mag body I found the feed lips were not parallel. I don't drop or otherwise abuse the mags. The other five mags measured about the same so were made this way.
Next I found ammo did not fit freely between the ridges in the side of the mag. The ridges were slightly clamping the brass. Don't know if this is by design but is a source of friction and seems wrong to me. The outside of the body measured approx 0.585 to 0.590 on all of my mags. It was a struggle but spread the body sides approx 0.010 so the outside measured near 0.600 inch. That was enough to stop the brass interference fit and the mag body still not drag in the mag well. Only test fired once since these mods but all worked good.... This is turning into work    - Joe

I found the same on all six of my mags. Adjusted the front to make the lips parallel.
Agree with you 100% and also think the tapered lips increase friction even though everything is smooth and polished.
Instantly improved feed reliability. Also found it stopped the nose dives when unloading a mag too... Joe

I bought four back in July from J&G Sales online about $22 each + shipping.
P/N 17696 retail blister package "Copyright 2016"
Identical to the two that came with my Gen2... Joe

Welcome from Texas... Joe

With slide lock removed, hammer must be cocked, and about one inch of barrel extended and held from the front of the slide.
Slide should move forward off of the frame.

Loctite Part No.22221 purple is the low strength threadlocker I tried first. It did not last long.
I then used Permatex #27100 "high strength threadlocker red" bought at auto parts store.
Requires heat to remove and 24 hrs to reach full strength.
Still holding after a single 100 round session.
I too may return this pistol if this doesn't work... Joe