C-100 Recoil Spring Weight?

[flyingbrass]

My C-100 has about 2230 rounds through it.  I replaced the original recoil spring at 1730 rounds with a round wire spring advertised for CZ compacts purchased years ago, probably from CZ USA.

At first, the new recoil spring was considerably stronger than the tired double wound factory spring.  The slide was more difficult to manipulate but felt about right when shooting.  Ejection pattern was closer in and consistent.  However, after a few hundred rounds the new spring weakened enough that ejection distance increased.  it varies and isn't consistent, but I'd guess that since about 300 rounds of use it has been at an average of 10 feet or a bit more.  I can't really tell if it has continued to increase.  CGW advises 6-8 feet ejection distance, which I also prefer: https://cajungunworks.com/how-to-select-the-proper-recoil-spring/

My practice loads are 115 FMJ at 1120-1160 FPS muzzle velocity depending on temperature.  I carry factory 124 grain +P Gold Dots.  Cajun says factory spring weight for metal frame compacts is 16#.  I'm planning to order from BH Spring Solutions: https://bhspringsolutions.com/index.php/product/cz-75-compact-recoil-springs/  They say 17# is stock for compacts.

Has anyone with a C-100 used springs from BH?  Any advice?

BTW, the flat wire green CZ compact springs won't quite fit on my factory C-100 guide rod.  I can shove one one, just barely, but it's way too tight.  Either the rod would need to be reduced slightly in diameter or replaced.  I remember reading several years ago that that green flat wire springs were not intended to be used on metal guide rods (something about the spring chewing up the guide rod? - don't recall).  When I changed recoil springs I tried a CZ plastic guide rod with both the CZ flat wire spring and the round coil spring that I've been using recently.  The plastic guide rod got chewed up enough to cause concern after only a few magazines of ammo.  I didn't trust it, so went back to the C-100's steel factory guide rod, which I intend to continue using.

As a side note, I've had this pistol since 2014, and it is still often a carry gun.  I shoot it some, but I've avoided putting a bunch of rounds through it.  The pistol itself has been extremely reliable over the years.  My reloads are in mixed brass with dozens of different headstamps of different ages and numbers of firings - worst case scenario.  The only malfunctions I've had were from the factory magazine springs weakening.  At about 2 years and 1100ish rounds I got a few premature slide lockbacks.  It turned out that both factory magazine springs had weakened just enough to allow the top round to slide forward enough to bump the slide stop (even though the slide stops on these are relieved - not really a problem of the slide stop shape).  Unfortunately, the follower design in the stock magazines did not allow Wolff replacement springs to fit.  I set the factory magazines aside and for good measure replaced the springs in my other aftermarket Mec-Gar magazines with Wolff (rated at +something, 5% or 10%?).  I've had no problems since then using the Mec-Gar mags with Wolff springs.

[flyingbrass]

I'm following up in case anyone else searches about this topic and finds this thread.  I've been using an 18 lb. CZ Compact spring from BH Spring Solutions in my C-100 for some time.  It's still working well at about 900 rounds.

At first, the 18 lb. spring seemed annoyingly stiff for manipulating the slide, particularly since there isn't much slide area to grip on CZ-style pistols.  This improved some after the spring took a set.  While a heavier spring would probably function fine and may even be better, I don't care to go any heavier to avoid overly difficult slide manipulation.

After the initial set, this recoil spring has maintained its strength better than others I've used.  It seems to be of good quality.  Ejection distance today averaged/clustered at about 8-9 feet away from the pistol, with a few closer and farther.  I'm using mixed brass.  115 FMJ bullets are going about 1120 FPS out of this pistol.  I'd classify this as being on the upper end of medium power/pressure.  BTW, my C100 had the shortest throat out of over a dozen pistols we compared.  I reamed it to better match my other pistols.

I wrote that years ago I started having premature slide lock with the C100's original magazines from the top round being moved forward enough to contact the slide stop.  I recently discovered that the culprit was the sharp corner on the lower edge of the breech face.  It would dig into and catch the top round as the slide moves forward.  I chamfered that corner and found that even my original magazines with their factory springs now work 100%.  Apparently mine was sort of on the hairy edge of working.  A new factory strength magazine spring or the Wolff +5% that I switched to in my Mec-Gar mags was enough to overcome the problem, but even a slight bit of spring weakening would reveal it.  Bevel that edge.

[jwc007]

Thankyou for posting this info as it may prove beneficial to others who own C-100's.
Too bad that Canik no longer makes them.

BTW, my C100 had the shortest throat out of over a dozen pistols we compared.  I reamed it to better match my other pistols.

Instead, I seat my Bullets so that the Bullet Shoulder does not bear up against the throat in my Cz's and Cz Clones.
Bullets, so seated will still run nicely in other Pistols.
The Barrel/Chamber throat area is what wears the most over time and I prefer to let mine wear naturally.
To each his own, however. YMMV!

[flyingbrass]

Yeah, it's a shame that Canik stopped making these types of pistols.

A friend and I did a fairly extensive comparison of throat lengths.  Even among the same models of pistols, throat lengths were all over the place.  My C-100 was the shortest of my pistols.  My friend's C-100, only a few serial numbers apart from mine, was about .015" longer.  That's actually a fairly small difference within a model from what we've seen.

My C-100 wouldn't accept some bullets loaded to acceptable COALs.  One example is the Hornady 115 XTP, which needs to be loaded relatively short even for "normal" throats.  I couldn't get it to plunk and spin in the C-100 at even .010" shorter than recommended.  Plus, you really want to seat a bit shorter than barely passing plunk to allow for differences in case lengths (which can also vary considerably in 9mm).  The short throat made this bullet practically unusable in this pistol.  I ran into a similar situation with some lead bullets that had a profile that the C-100's throat wouldn't accept until seated way too deeply.

I examined my C-100's throat with a borescope before I reamed it.  There wasn't much, if any, throat visible compared to other pistols.  Usually you see a well-defined throat area, but not with mine.  Despite using no pressure other than only the weight of the reamer and handle, the well-lubed reamer bit in quite quite hard as soon as I started to turn it.  Odd.  Due to this, reaming didn't go as smoothly as I'd like, but it worked out ok.  I had to ream a little more than I had intended to clean things up.  The throat was lengthened by about .040", which is about .020" longer than my current shortest, a CZ-75.  Accuracy apparently has not been negatively affected by reaming.

You're right that throat erosion is an issue with rifles, but it's not for handguns firing conventional pistol cartridges.  I don't like having to ream throats, but if needed and possible, I say go for it.  Nitrided barrels present a problem for this.  You can successfuly ream a nitrided pistol throat, but you'll ruin the reamer in doing so.  Reamers aren't cheap.