Ok Gents...

Today this should be the final modification to what has become my favorite daily companion. For any who missed the original thread where this piece was reborn... it's here:
We're way beyond Dremel now, Melted & Melonited 4516-1

Back in December of last year on that last page of that thread I hinted at exploring the use of a ISMI flatwire recoil spring. Well friends... Today I went and did that very thing.

Here are some of the bits I had previously been messing with
From top to Bottom:
16# factory round wire spring, measured OD of 0.406
Aluminum staked guiderod measuring 0.290 in diameter
Shortened CHP guiderod also 0.290 that I installed in December
4513TSW guiderod 0.236 diameter.
Umolested CHP guiderod S&W pn: 903370000 0.290 diameter


So anyway, It should be common knowledge that S&W doesn't make the 4516-1 revision single springs anymore so we've been relegated to the aftermarket to keep our guns running. I had some issues with springs stacking solid with the aftermarket which in the end was no big deal as I had decided to find a flatwire spring fitment for a contemporary arm that would also work in my gun.

What I settled on are ISMI's flatwire springs for the compact Glocks. While Glock calls these compact, the 19, 23, 25, 32 & 38 are really mid-size pistols of 4 inch barrel length and comparable in size to my 4516. Anyway, I ordered a couple ISMI flatwire springs to play with. One each in 15# and 18#.
Oh and just for the record, I do not now nor have I ever, nor do I plan to own any weapon made from recycled trash bins and/or of questionable metallurgy. Frankly I think they're all rubbish.

But I digress...

When the ISMI springs came in I did some quick measurements then some trial fitting. The springs measure OD 0.417 and ID 0.263, Near a perfect fit in the slide recess as I could wish for. The guiderod however would need some work. I did some test fitting using the 4513 skinny guiderod which was a bit of a sloppy fit on the spring but still cycling by hand and I could not detect any binding or fault with the flatwire spring. Next was to come up with a permanent guiderod solution.

Not having a lathe at home, I went down to the local machine shop today with a spare CHP guiderod and had them turn it down to 0.260 then part it off at 3.050 overall length. Took the part home and thoroughly polished it to remove every vestige of tool marks. Since the spring is gonna run pretty snug on this rod I wanted the surface to be a frictionless as I could make it. After polishing the rod measured at 0.255 which gives about 0.004 clearance all around when installed with the flatwire spring.

Here are the two flatwire springs 15# top 18# middle and the finished guiderod bottom, I know the finish looks a little odd but, that's only due to a light coating of grease.


Here's the upper with all the new bits installed, That's the #18 spring in there:


Nice, no slop & no bind ,fit in the slide:


Even though the new guiderod is a bit smaller than the hole in the slide, the fit and form of the flatwire spring is such that it serves as a bushing to keep everything in perfect alignment:


The new spring & guiderod fit perfectly. Hand cycling is very smooth much moreso than with any of the rouldwire springs I had in there. My "seat of the pants 'o' meter" tells me there is a bit more spring force at installed length holding the slide in battery (about the same feel as my Shorty with a new set of nested springs) which should equate to a few milliseconds of delay in unlocking. Retracting the slide fully to the rear I can feel a difference in the pressure curve between this and the old springs. The flatwire seems much more of a linear smooth even increase in pressure 'till fully back whereas the old spring seems a little weak and the start with little increase in pressure the first half inch or so then the pressure spikes up.
Well, we'll see how well she performs at the next range outing. I'm quite confident she'll run like the proverbial swiss watch


So, Why the flatwire spring you ask? Well I think S&W saw there was a problem with the -1 revision spring and that's why they went with the dual nested spring on the -2 and up guns. I've essentially done the same thing S&W did just with a single spring instead of two.
Essentially there are two reasons why I chose this arrangement; First, given a fixed amount of space such as the installed spring length in a 4516, you can put a great deal more spring in there with a flatwire than with a roundwire spring. Specifically, look at the coil count. The stock 16# roundwire spring has 19 coils whereas the flatwire 18# has 31 coils. That's a significant increase in spring power. Secondly, These springs are purported to last upward of 100,000 compression cycles, I like that. Does that mean I'll never change springs again? Certainly not, But I do expect these to last & hold their weight rating a good deal longer than your average roundwire spring.

Of course time will tell. I've got rain in the forecast into the middle of next week so it may be a bit before I can get to the range for some testing. And I want to get a 20# and a 22# and see how well ranger +p runs in this gun.

Update to follow after Range Day

Cheers
Bill

Great info! Thanks for sharing your experience with changing the rod and spring.

Sometimes you just have to think out of the box.

Please report back on how it works, when you get some range time.

Bruce

Bill,
Holy cow, that's a great find!
I'll have to try that setup on my 4013 to 1013 10mm conversions.
I hope Dave @ ISMI has some heavier springs.
Regards,
BM1

Thanks BMCM for another outstanding thread!!

Very informative and interesting. I'm looking forward to your range test results! Regards 18DAI

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7 +1 Rounds of hope & change

BMCM I am a shooter with no engineering or machining experience or skills. I do have a rudimentary understanding of the 4516 design.

If you don't mind, I have a question for you. Is there a flat wire spring made that will go on the factory OEM 4516-1 guide rod without any modification and assure function?

If so, is it possible to use one in a 4516 no dash, provided the guide rod is identical to the 4516-1? I ask becuse I'd like to pick up a 4516 no dash and send it off to Coal Creek for meloniting. Then install Novak low mount night sights on it. Sort of a matching off duty gun for my factory Melonite 4566.

Thanks for your time! Regards 18DAI

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7 +1 Rounds of hope & change

Well Sir, I seem to recall the no dash guns have the nested dual springs but I'm not sure. If that is the case then the skinny .236 guide rod is in there. An ISMI spring will run on that it's a bit flappy loose though and I only test fit like that, didn't shoot with that setup.

Anyway about the spring, all the flatwire pistol springs I know of are made to run on a 1/4" guiderod. The OEM dash 1 rod is simply too fat plus it's aluminum. I'd be leery of running a flatwire spring on an aluminum guiderod anyway. They get chewed up enough as it is with the factory roundwire spring.



Why not just do like I did with the CHP rod.
it's pn: 903370000
Cost me $20 to have it machined to my specs plus the whatever the original cost was...$17ish I think.
It's solid one piece stainless and polished to a mirror finish is smooth like a hydraulic ram on that flatwire spring.

If you want to do that I can whip up a drawing for you to take to your local machinist.

If you don't mind my asking, wouldn't a dash 1 be a closer match proportionally to your 4566 since the no dash has the stepped frame and top rib?

Cheers
Bill

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Because they don't make a .46

Thank you BMCM!!

Yes, you are right. Proportionally, a 4516-1 would be a better match to my 4566M.

But I like the slightly lighter 4516 no dash and don't have one in the "herd" yet. Plus, a beat up 4516 no dash is easier to come by at a cheaper price!

Thanks again! Best regards, 18DAI

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7 +1 Rounds of hope & change

Yeah, I suspected you were after the lighter one Easy enough to make it work either way.
I'll gladly help anyway I can.

Cheers
Bill

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Because they don't make a .46

Man it's been a crazy week 'n' a half down here. All last week were getting a monsoon, my driveway was literally a mudbog, burm is damaged at the Adams Co. range so it's closed, then Friday I get summoned for jury duty. Monday morning this week at the courthouse for jury qualification then again this morning for the vior dire. Personal injury civil case. My luck turned though when the plaintiff's mouthpiece asked me what I thought of tort reform... So I told him and was soon thereafter excused Off I went with my kit to the Concordia Parish range to make some noise

So, I get to the range and have the place all to myself. Set out a blank backer just for something to shoot generally at as I'm focusing more on how the gun behaves. Get set up with my little .45 and a few mags full of TZZ hardball. Now let me tell ya this TZZ stuff is rather warm. TZZ head-stamp is "Israeli Military Industries" I actually think this stuff is old subgun ammo. We used to get issued this for practice during my Coast Guard Pistol Team days. After practicing with this stuff, WCC Mil Match hardball felt like .32 ACP. The TZZ stuff is noticeably stouter than +P Ranger T.

I fill a few mags with this TZZ stuff and with the 18# spring in the gun, commence sending rounds downrange. I note the slide is moving along rather briskly and feel a slight but sharp impulse as it impacts the frame each shot. I also note my brass is coming out rather briskly landing about 3-4 o'clock and 10+ feet away. Ran some Gold Dot though too and while those loads were much tamer I still felt I was a bit under sprung. Time to jam the 20# in there and see what's what.

Here's a shot of the bits on my bench after I got back home, the 18# is there on my custom rod and the 20# below.


And this is the 20# spring installed.


Now I've got my Shorty along also with a brand new set of nested springs inside just to compare with. In handling both weapons and exercising the slide here's what I discern. The 20# ISMI spring feels about the same as the S&W nested set, perhaps a tad heavier. The most prominent difference I can tell is in that first quarter inch of slide travel wherein the breech unlocks and the barrel cams downward. from what I can feel, the ISMI 20# exerts a lot more pressure at this point beyond what a new set of nested springs does.

So, I try the same routine with the TZZ ball this time with the 20# in there. OK! I think...Now we're definitely on to something. I'm shooting with either hand both supported and un-supported, I note no battering at all, surprising decrease in muzzle rise, faster recovery, empties going about 4-5 o'clock and 6 feet or so. So far so good, now I try some other stuff... run some Gold Dot through, no issues whatsoever and even faster recovery. +P Ranger T? same... just a pure pleasure to shoot. Some 25 year old Hydra-shocks from my oddball ammo bin? same.

Ok, I think... Let's see if we cam make this thing choke. In my bag I've got some WCC supermatch wad-cutters, TZZ 185 mid-range wad-cutters, and some Federal 185s. Surely with a 20# spring in here I can jam it up with this stuff. No go, Even with that heavy a spring in there it just keeps going. Hmm! perhaps if i randomly mix a bunch of different stuff in there it'll choke. I stuff some 7 & 8rd mags full of a mix various wad-cutters, ranger, gold dot, Hydras, whatever I got. I nearly started to giggle shooting this stuff... Sounded like "BANG pop Pow BLAM poof pop BANG blam" Still nothing, just eats everything I shove in there. Stuff a fired case midway down in a mag under a wadcutter... Nope, chambers the empty & click... slingshot and keep going. Wadcutter empties don't go as far but that's to be expected.

Now I am really pleasantly surprised, I've tried everything I had available to get this gun to choke and it just keeps running.
And to find that +P Ranger is such a cream puff with this setup and in a compact pistol to boot just icing on the cake. I think the 20# ISMI spring is just the ticket and I'll be stocking up with a few spares.

for 18DAI... I think this would be and excellent option for modding a no-dash gun, I'm quite confident 110% reliability is achievable. Boy wouldn't a no-dash look sexy in black?

Well Gent's it been a great day at the range, My girl is back on CC duty and I'm a happy camper.

You know what? I think I'm gonna start looking around for another Dash1. I had so much fun tuning up this one I think I'll roll another... with a few refinement perhaps

Oh and lest I forget...

Cheers Gentlemen
Bill

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Because they don't make a .46

Thanks for the great review BMCM!!

I appreciate the info. Roger that. Best regards, 18DAI

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7 +1 Rounds of hope & change

BMCM-If I cant get my dash 1 up and running as it should, you may have that one before you know it.

Very sweet set up BMCM.

Of all the 16s I like the no dash the best. Had four or five over the years and never could get one to choke, even with an empty.

Yes, all the no dashers I had were OEM with the nested springs.

Nice work Mr. Craftsman!


Cat

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Think for yourself.

I love the idea of using this spring, I noticed your offered to send drawings to another member I wondered if I could bother you for a quick drawing to take to the machine shop?