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Discussion Starter · #1 ·
Hello All,

I picked up my new FNS 9 from FFL about three weeks ago and was finally able to get to the range this past week to put some rounds through her. Having shot the FNS 9 previously, I was not at all surprised at how well it performed. No hiccups whatsoever. The trigger was not only 'ok', but actually fairly smooth right out of the box (maybe I got lucky) without any grittiness. If anything, maybe a tad heavy - but I will take that in a carry pistol. More accurate than I am, that's for sure.

My question is this; has anyone else noticed the recoil spring 'rides up' the barrel unlock surface? The recoil spring sits in a curved groove in the barrel unlock surface, however, after shooting (and even after simply racking the slide a couple of times), the recoil springs rides up on the barrel surface. It seems to move a fair amount as well - maybe 1/4 inch or so.

This may be absolutely normal, but before I start travelling around to gun shops asking if I can take down their FNS 9's to see if they do the same, I thought maybe I could get some info from the forums. I am hoping this is normal, as I hate to have to ship it off to FN, unless it is necessary.

Appreciate all the feedback and posts . . . I have learned quite a bit from reading them.

Thanks in advance. I appreciate it.
 

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Hey, awild.

It only does that when you take off the slide.

When you have it seated correctly and put the slide back on the frame and while shooting, it stays right where it is supposed to be.

Then when you take it off again, you will find it sticks up a little.

I think this is what you are asking, right?

Doc
 

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DrDenby said:
...When you have it seated correctly and put the slide back on the frame and while shooting, it stays right where it is supposed to be.

Then when you take it off again, you will find it sticks up a little.
DrDenby has it right, but didn't explain it fully.

The way you position the base of the guide rod when INSTALLING the recoil spring assembly is different from the position the base of that assembly takes when the gun is used or the slide is cycled.

When you first go to install the slide ON the gun, the top half (or so) of the recoil spring base rests on the barrel lug. But as soon as you put the slide on the frame and install the slide stop pin, bottom part of the base is pressed against what is called (in some guns) the receiver stop. The receiver stop is a location on the frame where the base of the guide assembly rests; it's an UNMOVING part of (or in) the frame that gives the recoil spring something to compress against. (That location/functional position of this spot has different names in different gun designs; in some cases it's a pin, a block, etc., but they are all necessary if the spring is to compress and store recoil force needed to feed the next round.)

As the slide moves to the rear, the base of the barrel moves away from the guide rod assembly base, but the base itself stays pressed against the receiver stop. Because the barrel is moving to the rear and slightly down (as it separates from the barrel), the bottom portion of the guide rod assembly is pressed down (by barrel movement) fits more iinto the receiver stop area.

hat slightly altered position you are puzzled by is the position the base of the guide rod assembly remains in until you take the slide off' it's why the guide rod isn't pressed against the barrel as it was when you last installed the guide rod assembly.. (Note: nothing lifts the base of the guide rod UP to it's INSTALL POSITION, as there's no need for it to be "up." It only needs to be "UP" during the slide installation process. When you remove the slide you see the base of the guide rod as it was in it's "working " position, rather than it's "installation" position.
 

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Discussion Starter · #7 ·
Excellent! Much thanks to DrDenby and Walt. I appreciate the responses - which do make perfect sense. I was worried that if the spring assembly slipped off the lug while firing, my face would be in a world of hurt (not that it already isn't - lol). Many thanks.
 

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awild1 said:
I was worried that if the spring assembly slipped off the lug while firing, my face would be in a world of hurt (not that it already isn't - lol)
A slightly different way of looking at it:

Several other parts of the gun mechanism will keep the slide out of your face. :) While it doesn't seem to make sense, field strip your gun, remove the barrel and recoil spring assembly, and put the slide back on the gun. You won't be able to move it any farther to the rear than before... But there's more at play protecting your smile!

As the barrel goes to the rear and slips off the recoil spring assembly, the rear of the barrel (including the barrel lug) drops down. The recoil spring assembly isn't PREVENTING that movement -- it's simply storing energy from that movement for later use.

The front of the recoil spring assembly stays in contact with the slide and it's rear is in contact with the frame. The front of the barrel is still sticking out the front of the slide and the rear of the barrel (and the barrel lug) will also end up dropping back and coming to rest against a different part of the frame (at the locking block/receiver stop/slide stop or barrel link - depending on the gun's design). If all of that fails to stop the slide from going to the rear, the parts mentioned in the "bolded" segment above must also fail... They'd all have to fail simultaneously for the slide to continue to the rear. Not very likely.

The main function of the recoil spring assembly is NOT to PREVENT RECOIL, PROTECT YOU, or STOP THE SLIDE'S REARWARD MOVEMENT -- it's there to store force that can later be used to load and chamber the next round.

Believe it or not, a lot of guns can be fired without a recoil spring or recoil spring assembly installed; the gun isn't damaged by the experiment, but it won't load the next round. (1911Tuner, a highly regarded 1911 expert who participates on other forums, has done this a number of times. He lives relatively nearby and I've visited with him in the past. There's even a video of him doing this. He has done this with the same gun many times and there is no observed damage to the gun or shooter. When others try it using his gun they say they don't notice a great difference in felt recoil...As he notes in the video, he's using a gun he built that has both a CAST SLIDE AND FRAME.

This whole cycling process is actually much simpler than most realize, but also more difficult to understand than you'd expect -- a sort of oxymoronic process: simply complex.

https://www.youtube.com/watch?v=Xyis5h9MvUU


YouTube has one of a Glock done the same way... not as well done, but the results are the same.
 
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