545 mags in FNX45

Of course the real potential here will be the ability to use the 510 mags in the FNX. People have been asking for an FNX-10 Tactical for years. One of the aftermarket barrel manufacturers could have always made a conversion barrel, but without an engineered magazine it would be a crap shoot if the thing would run correctly.

That’s a bit of a gamble tooling up for a barrel with no viable magazine. While 10mm may run just fine in an unmodified .45 magazine, it likely would not. How many potential customers would want to start tweaking the feed lips on their $50 magazines? Especially if the end result could be that the mag ends up working poorly with either caliber.

But now with factory engineered mags that will work in the FNX frame, it may be easier to get a barrel in 10mm. If FN doesn’t want to make an FNX-10 for is, now maybe we’re a little closer to making our own.

Thought I would add what I did today as I finally picked the FDE 545 this afternoon. I have a FNP-45 and FNX-45 T and 10 mags.....9 of them are the old style follower from the FNP days and one is the newer follower from the FNX. The old mags work in the FNX but the newer mag will not work in the FNP. So to test if any of the 10 mags would work in the 545, I jammed one in the 545 and no go as it would not lock in on the mag catch. It was close but no cigar. So I took out the trusty Dremel and sanded off the rear of the baseplate on one of the FNX mags. The sanding went down to the bottom of the tube, cleaned it up and inserted it in the 545 and she works fine. Locks in, locks back and drops fine. So I now have 11 15 round mags and one 18 round mag for the 545 and won't have to spend $60 for new ones from Midwest. Are they ugly as hell ?....You Bet They Are.....but they work and about one minute per mag on the sanding saved me $600 on new 545 mags. If you don't mind FUGLY, give it a try on one. They work fine in the FNX also as nothing was altered except a small amount of plastic being removed at the rear of the mag basepad. The removal allows the rear of the mag to seat firmly and gives just enough clearance at the bottom of the grip insert.

Just got back from the bunker and need to make an update. The modification I did does work as far as locking the mag into the 545. The followers from the FNP mag days are different than the FNX -45 T followers. FN expanded the width of the newer mags at the top over the FNP mags therefore the new followers WILL NOT fit the older mags. I discussed this issue with one of the techs at FN last year. Due to the vertical tip of the follower that hits the slide release, it is smaller on the old followers and wider(front to back) on the newer ones. This difference causes the slide to NOT lock back if you use the old style FNP mags with the old slimmer follower. That smaller follower, when inserted into the gun, slides past the slide stop tab and will not lock the slide back. Both old and new mags will load rounds and tomorrow I will test both mags at the range for function. My Dremel work allowed the FNX mags to insert into the 545 and lock it back, but the old FNP mag follower will not lock the slide. Not a big deal as competition shooters often don't have lock-back slides. My old FNP mags have always worked in the FNX so I need to check the surface area of the slide lock tab on both guns. My guess it that the FNX slide lock tab is larger than the older FNP tab. I'll check that tomorrow.

Garrett........I will hit the range tomorrow for the first shots of the 545. My FNP-45 is literally more accurate than my FNX. It is a tack-driving laser beam and has been for 10 years. The FNX is right behind it so I won't get much sleep tonight waiting for my range to open. The 545, IMO, is a 509 on testosterone, but not that much. FN did improve the 545 trigger over the 509 by a large margin. I tried everything in the book to get my 509 to have a better feeling trigger. Changed all the springs and sear in the trigger housing several years ago but still was not that fond of the 509. Polished every single piece to a mirror finish, polished the striker safety plunger, smoothed out the striker channel, etc., but gave up and sold it. The 545 ergos over the FNX are appealing. I took the square corners off my FNX grip and rounded it out and stippled it with my favorite point. Made it much more comfy. I concur that it might be better to modify the 18 rounder.

I'll get around to checking out the 18 rounder tomorrow and seeing how it might be modified for my FNX. I just need to find someone locally with a 3D machine and I'd create my own basepads to fit both guns...similar to how the Glock 21 mags fit on my Glock 30S gun to give me 13 rounds with the sleeve taking up the slack. It was a happy day when I put my 545 in my FNX holsters and they fit at about 98%. Good to go there. I'll have around 300 rounds done tomorrow with the 545 and if it passes with no malfunctions, I'll be impressed. If all the old FNP mags work, even not locking back, I'll be even more thrilled. I'll report here tomorrow PM.

MGW shipped pretty quickly. Mags arrived today and I started cutting & hacking. Not bad, overall.

I’ll try to get out tomorrow and take it for a test run before I modify the other basepad. But it locks up easily and it locks the slide back on an empty mag. It holds 18 without excessive force required for the last rounds and will still lock in place with a full mag.

Now I just need to find someone with a 545, just to see how funny my modified mags look in that gun.

FNX mags, Left to right:
Flat basepad - 14 rd
Standard - 15 rd
Apex basepad - 17 rd
Modified 545 basepad - 15 rd
Modified 545 basepad - 18 rd
Unmodified 545 mag