CZ P-07/09 OEM Hammer modification question

[Larry F]

I'm in the midst of upgrading my CZ P07 pistol, and have shied away from doing anything with the hammer beyond polishing and assumed the only practical upgrade is a CGW or CZ Custom race hammer. 

However, ref http://www.brazeauracing.com/firearms/p0xhammers.html.  Anyone have experience with this particular OEM hammer modification and can provide meaningful input?   Thks, Larry

[Earl Keese]

 If you want to modify your P07 hammer, you don't need to build consensus,  just do it. Then, when it wears out quickly and becomes unsafe, you can replace it with a Cajun hammer.

[Wobbly]

If you want to modify your P07 hammer, you don't need to build consensus,  just do it.

True. The hammer doesn't care at all about consensus.

[M1A4ME]

I worked on one hammer, decades ago, for a Combat Commander.  Came out pretty good.  Zero issues afterwards.

But, it's not an easy thing to get right depending on exactly what you're doing.

A shorter shelp/notch where the sear sits should make for a crisper/shorter trigger pull.

It doesn't look/sound like you're going to be filing/stoning/polishing the surface where the sear contacts the hammer.  Just shortening that area to reduce the necessary distance the sear moves to release the hammer.

You'll need to be careful to insure the patch you leave, where the sear sits against the hammer is even from one side to the other.  You don't want it to be angled.

While the hammer surfaces are heat treated to make them hard and improve wear/increase the life of the hammer I have not idea if removing metal from the front of that surface will effect that corner where the untouched surface (sear notch) meets the vertical surface you removed metal from will wear quicker.  That's another thing you need to keep an eye on when you're done and using the pistol.  If it starts to round off or get burrs on it you'll need a new hammer.

The aftermarket hammers are made with that short shelf in that notch so the sear doesn't have to move far to release the hammer.  So the surfaces are heat treated where the sear contacts the hammer and that corner is heat treated on the vertical side above the notch/shelf.

Factory P07 hammer above and P07 hammer from CZ Custom below.

You can see the differences between factory vs. the other one.  Looks like what you're wanting.  The CZ Custom hammer will be properly heat treated where a modified factory hammer would not be - both sides of that corner where the sear slips off the hammer when you pull the trigger.

[Larry F]

SCORE so far: 1 constructive comment and 2 Fanboys 2 cents worth. 

I'm pretty experienced in wear on parts and am really only interested in real user experiences in reworking their OEM hammers.  Thks, Larry 

[Earl Keese]

SCORE so far: 1 constructive comment and 2 Fanboys 2 cents worth. 

I'm pretty experienced in wear on parts and am really only interested in real user experiences in reworking their OEM hammers.  Thks, Larry

You mean one comment that said what you wanted to hear. Like I said, you wanna mod your hammer...mod your hammer. If you're as experienced as you say, what's stopping you?

[Grendel]

SCORE so far: 1 constructive comment and 2 Fanboys 2 cents worth. 

I'm pretty experienced in wear on parts and am really only interested in real user experiences in reworking their OEM hammers.  Thks, Larry

1. If you don't want to read contrary opinions, don't post your question in a Forum.

(Forum: a medium for open discussion)

2. No one here is privy to your level of expertise unless you tell them in your OP.

3. 23 posts and snarking off to other long time members and an administrator is unlikely to win you many friends here.

[Larry F]

Message recieved and accepted.  I generally research the effects of a possible change before beforehand to minimize redo's.  Inputs like M1A4ME's are very helpful and appreciated.  Other intuitively obvious observations are less helpful even to a novice CZ user such as me are less helpful and sometimes frustrating in cutting to the chase on an issue.  I overreacted and apologize to those affected, here and in prior postings.   Thks, Larry

[Grendel]

Thank you.

Hammer geometry and sear engagement is crucial. If you are confident and careful, with stoning and/or filing, it should be okay. Go slow and check often, I think is key here.

In my case, I would probably make sure I had a spare hammer on hand just in case I banjoed the original.

[Wobbly]

....just in case I banjoed the original.

Score so far, 1 offensive 2 cents worth.

This Admin owns a banjo and I am highly offended by your callous and insensitive comment. I'm a card carrying member of LBM (Loud Banjos Matter) and we just might serenade you tonight with 200 choruses of Dueling Banjos if you're not careful.

Larry, hope you sleep better tonight knowing you're not the only one suffering these indignities !

[Larry F]

Grendel - I buy your comment on how sensitive the sear and hammer engagement to change is. 

My first lesson learned was early on when I blued the hammer and sear mating surfaces and saw they were not fully engaging. I found the leading edge of the sear was cantilevered across it's face.  The guys at CGW indicated that this is common with the OEM sears and they true the leading edge of the sear and replace the sear pin as standard practice in their upgrades.  I did the same and the hammer roll back increased and the the trigger bar started catching on the disconnector.  CGW's input was that the action timing was right on the edge when the pistol was built and I had thrown it out.  My roller OD was measuring .218" and going to a .225" roller put it back to working right, i.e. a little change one way or another can have a big impact.

What I'm trying to accomplish with this particular pistol is to understand how CZ pistols work and decide if I want to replace my older 9mm Sig P228 pistol for the more powerful 40 caliber P07 as a carry gun or to pass it on to another party.  It's not a fair technical comparison as I had first hand support from Robert Burke (The Sig Armorer) in tuning the Sig pistol and and am working from distance in tuning the P07.  Sorry for upsetting of your regular posters as, as while I'm sure they were well intended, they were short on technical explanation.   Thks, Larry

[M1A4ME]

Larry, seems like I remember, a few years back, several members bought P07/P09 pistols that had "leaning hammers."  The hammer was not straight /perpendicular to the frame/slide.  Evidence was the hammer rubbing the slide of the notch in the back of the slide and just looking at it.  That might also cause an issue with the sear and hammer not being "square" with each other.  Something to take a look at when buying a P07/P09.

Grendel mentioned go slow and check.  While it takes some time to do and gets darned aggravating it results in a good outcome.  When I changed hammers in my CZ75 Compact I had the left side safety lever out of the frame to stone the cam on the shaft that blocks sear movement and back in to see if I'd removed enough metal to make it work without being sloppy right at 24 times.  I was getting so tired of it but the result was a safety that absolutely locks that sear in place with no slop between the cam, the sear at all.  Like they say, you can take metal off.  Putting it back on is darn difficult.

Good luck with it.

[radagast]

   Frame/hammer contact was just one of the problems I had with my 07, but at rest everything appeared normal. there was pressure pushing the hammer portside during the DA cocking sequence, so I followed the frame sanding process I found here in the forum to correct it.
   The improvement I got through polishing and sanding were so dramatic, I never felt the need to change any parts at all ! Now I'm anticipating replacement of the trigger return spring and the FP retaining pin since it's well over 5000 rounds.

[Larry F]

My hammer and sear seem to be pretty square with the frame and with each other.  I tried to check the sear pin and hammer pin separation distances on both sides of the rear insert and didn't measure much difference, the hammer looked to be sitting straight and doesn't show side wear, and the front of the sear ledge showed contact rubbing on about 3/4 across it's width.  I did smooth the sides the hammer and the insides of the frame per the tips from users. 

I talked with the guys at CGW and learned the leading edge of the MIM sear isn't machined and cants from one side of the sear to the other.  They stone the cant square on the upgrades they perform as well as on the pistols they sell.  They also change sear pin with one that reduces the sear's side to side play.  I did both but took too much metal off the sear's leading edge in getting it trued up with the hammer face and knocked the action out of time.

One of the reasons I've haven't installed a CGW hammer yet is, while it's a better design and material, I don't have a good feel for how much change it's going to make compared to how well I got the gun setup now.  What I didn't like about the SA trigger pull was it was too easy to trip the sear and fire a round before I intended to.  I've changed the OEM sear spring twice and I can ride the trigger without tripping the sear and the feel is closer to what I've been used to and the measured trigger pull weight is under 3.5#.  CGW has a new stiffer yet spring I'll check next.  I'm on about the 10th teardown and reassembly - not close to your record.

Also the CGW and CZ Custom hammers are used with the OEM sear which has a rounded edge and, at least in my mind, it may not live up to it's reputation as a fix all solution to my problem.  I've read that you have one and have a standard hammer build in another pistol that worked as well.  Can you expand on what your experience has been?  Thks,  Larry
   

[M1A4ME]

Larry, if you mean me:

I have two P07s (.40 DUTY and a 9MM new model) and two P09's (9MM and .40 S&W).  Only the P07 9MM has a replaced hammer.  The other three are still stock except for CGW reduced power firing pin block springs and trigger return springs and some stoning on the P09 9MM.

The P07 DUTY .40 came out of the box with a nice clean/crisp 3.5 lb. SA trigger pull and around an 8.5 DA trigger pull.  It is now down to just above 3 lbs. on SA and I haven't measured DA as I never use it.

The P09 9MM came next and had a pretty decent trigger out of the box.  Pull weights were similar to the P07 DUTY but not as crisp in SA.  I did some stoning on the sear and it helped some but didn't make it identical to the older P07.

The P09 .40 was next and the trigger is okay (don't remember the pull weights) but not as clean/crisp as the first two plastic Omega pistols I bought.  Not as accurate as the P07 either, close though.

The P07 9MM was last and had the worst trigger of the bunch.  Rather than do a bunch of spring changes and polishing, etc. I bought that CZ Custom hammer.  It helped but is still not as nice as the first P07 or the first P09.  Better that factory.  Good enough I never attempted to change out more parts or do more polishing. 

None of the four are as good as two of my steel framed CZs I replaced hammers in.  Nothing fancy about those two hammers but they are different than the stock factory hammers for a B model pistol.  They are the "repro" spur hammers sold by CZ USA   I have a Pre B CZ85 and like it.  I wanted to make my CZ75 Compact like a CZ85 and bought the spur hammer and CZ85 ambidextrous slide release levers and safeties and did some frame work to install those.  The notch in the hammer for the sear is really small/short/sharp comparted to the factory hammers.  No idea why but it makes for a 3 lb. SA trigger pull (with factory sear in the Compact and CGW adjustable sear in the CZ75B .40) so crisp the only way you can make yourself believe its really 3 lbs. is to do a few trigger pulls with a trigger pull ga.  Really, awesome trigger feel/pull.  The only thing I have lighter is the CZ Tactical Sport .40 (which is too darn light to carry and I have to be careful at the range with it, too).  The CZ75 Compact and CZ75B .40 have the factory hammer springs in them and still have a wonderful 3 lb. SA trigger pull.  I don't need anything lighter because (I now I keep saying it) it's so crisp it feels lighter.  It is the crispness that counts, for me.

The Omegas are different than the CZ75s inside and I really have not worked on my Omegas like I have the CZ75 types.

One more thing, while working with other brands/models of pistols the last 8 or 10 years I've found that my belief that a nicer trigger makes a gun shoot better groups really hasn't been true for me.  But I still appreciate/like a nice trigger.