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Smith and Wesson J-Frame Apex Trigger Kit

Discussion in 'Gunsmithing' started by SiGlockBoy, Nov 7, 2012.

  1. SiGlockBoy


    Likes Received:
    Mar 4, 2009
    Like many people who own and carry Glocks, I carry a Smith & Wesson J Frame Model 638 also. Forget the
    hype about DA only in court as I've not seen one case in 30 years that has resulted in a prosecution for cocking the hammer on a DA/SA revolver in a justifiied shooting.

    No, I'm not a lawyer but I read as much as I can from people who do go to court. But I digress as this is not about that.

    I am placing this here instead of the gunsmith section(Changed my mind) as I believe it could be of help to shooters as well as others who like to tinker. I also feel it's more user geared even though it has technical goo mixed in.

    What this is about is that many people have been talked into the DA only versions like the 442/642 and when
    the trigger pull becomes too much for them, they want to sell an otherwise perfect gun to find something that
    has less pull. Too many people jump on the bandwagon without question or knowledge. I personally think the 638
    is the best choice and don't want to have the wonderful SA removed.

    **Please keep responses to trigger pull and let's not get into the debate of DA vs. SA as it's been talked about enough. Just remember not everybody is strong and healthy. Maybe someone has weak hands due to illness or arthritus or "trigger finger". Yes it's a real issue and my wife has dealt with it for several years now. Basically the tendon sheath irratates the tendon enough to start to form a bump and not allow it to slide through the sheaths anymore.

    She can grip something and the finger won't open back up on its own. She likes her GLock 26 and luckily can still
    pull the slide back due to using the whole hand strength. Others can't.

    I had a customer ask me what could be done to make the trigger pull more acceptable to her hand situation. She couldn't pull the stock weight back more than 10 times before finger failure. Even at that, it hurt each and every time. Recoil was acceptable but the trigger pull was just downright effecting function as well as keeping it on target. She has issues pulling the slide back on most autos, so that doesn't offer a reasonable alternative. Most small autos also have heavier trigger pulls than the revolver does. Some reaching 20+ lbs in DA.

    What to do? Well, a trigger job was definitely in order. That is a given. It helps and with all the jobs I've done
    over the last 20 years, Slicking things up can remove a lot or a little. Most the time I see a measured 2-3 lb loss
    just from cleaning up the surface of the hammer, trigger and rebound slide as well as all the other little rubbing
    bits inside. The largest gain is usually in the rebound spring and everybody has their favorite combination of springs that solves the issue. Wilson gives you an assortment that tends to confuse most instead of helping them. They also don't solve the issue of balancing the firing pin which results in primer strike issues. Sometimes you get it perfect and sometimes it borderlines the light primer strike issue.

    So what about Apex. They did some nice things to the M&P line. So I have watched the J-frame Duty/Carry kit since it came out last year and it seems to be looking at things through clear eyes. They have done thier homework in regards to the zen of balance. THey also went one step further with a lighter firing pin spring and firing pin itself.

    Their claim is a 3lb loss from the kit alone. I'm always leary of snake oil remedies but this one seems to have it correct. So to start with I measured the customers 642 and found a whopping 15lbs 8oz pull in DA. That seemed high to me, even with a J-frame. I have a bone stock 638 and it measured 11lbs 9oz. So the trigger job was 1st and what follows is my techno geek measurements from the change. Best of all, everything is pretty much reversable except the polishing.

    If you haven't done a trigger job on a revolver, please stop. Learn as much as you can and go through one with someone before you attempt it. Put the dremel away. With the MIM parts, you can ruin a couple hundred dollars in parts quick. Even worse, you can create a dangerous firearm for you and everyone around you. I'm not here to teach you how, just show you how much change you can expect. Go to school or read Kuhnhausen's wonderful books on these subjects.

    I didn't create any of this knowledge and not very many others did either. I just learn and execute these techniques and from experience, have done a decent job so far in life. I've not had anyone complain yet.

    After the trigger job was done, I measured the pull and found it went from 15lbs 8oz to 13lbs 9oz. About a 2lb loss and much smoother through the stroke. OK, I'm happy there and with light stone work is about on par from what I usually expect.

    This is where careful work is done. Too much on MIM parts and you can go through the surface hardness and get into the soft side of the part. Then your wonderful smooth job will go downhill in a matter of a couple hundred rounds and get rough as well as ruin the part.

    Then I installed the Apex parts. Very easy to do and requires nothing more than a good sense of mechanics and a couple tools. The rebound spring is a 2 second job with a phillips screw driver in the spring and a little pressure. If you have more issues than that, something is not going right. No flying springs or burst blood vessels should be involved. There are videos on the process out there if you look. I'm not going into that here. One thing I always stress to people is that if you are shaking, or putting more than normal pressure on a part, you are doing it wrong.

    After I completed that and reassembled, I again measured the trigger weight. This time it went from 13lbs 9oz to 10lbs 8oz. If I use a little math, that comes out to a loss of about 3lbs. Overall the drop from an original 15lbs 8oz to 10lbs 8oz is a total loss of 5lbs. Now that is something that makes me happy.

    The customer tried the first dry fire and made it snap
    with a smile on her face. Now she can pull the trigger and not feel her finger is in pain. It is also still above the
    8-9 lb zone in which most people will agree is the beginning of the danger zone of being to light. That said, I feel it is well within the safe zones of operation and couldn't make it go click with light catches on jeans or other objects I tried to drag it against. Also you should be using a holster that covers the trigger so those accidents don't happen anyway. Either way the pull is still at a safe weight and no issues outside of Murphy should exist.

    So to keep things real, I am very pleased with the additional loss in pull and still maintains a perfectly acceptable level of safety in a weight that makes it much more pleasant for people with some issues to control and fire accurately.

    Now for the technical bits. I measured weights of course and you can judge those for yourself. A digital scale was used to perform those measurements. All other measurements were done with a dial caliper to the thousandth position and yes, it can vary a little. Nothing is perfect and I measure 3-4 times each time. Call it OCD or just being careful.

    Here's the facts:

    Stock J-Frame Spring lengths and wire diameters.
    *Stock Hammer spring = Length = 1.748" with a Wire Diameter = .034"
    *Stock Rebound Spring = Length = 1.039" with a wire Diameter = .035"
    *Stock Firing pin Spring = Length = .212" with a wire Diameter = .012"
    *Stock Firing Pin = Length = .213" with a diameter = .070" ***This is pin only and not the entire body of firing assembly.

    Apex Kit Spring lengths and wire diameters.
    *Apex Hammer spring = Length = 1.795" with a Wire Diameter = .030"
    *Apex Rebound Spring = Length = 1.181" with a wire Diameter = .032"
    *Apex Firing pin Spring = Length = .218" with a wire Diameter = .010"
    *Apex Firing Pin = Length = .222" with a diameter = .070" ***This is pin only and not the entire body of firing pin assembly.

    ***The pin nose also has a sharper point Vs the stock being more rounded. I'm assuming in an atttempt to help primer strikes.

    You can see a common theme here. Most the Apex springs are longer in fact but the diameter is always smaller and therefore a little weaker or lighter if you will. The trigger pull is so much lighter that you really can tell the difference and wonder why it doesn't come from the factory this way. It is still perfectly safe, it's just more useable by a wider audience. Sig has different trigger kits to reduce pull and weight and length. Why not Smith & Wesson? Maybe too many lawyers hanging around from the bad days whispering in the ears of executives.

    I tried snap caps and cases with fresh primers to see if the primer would be dented and with Winchester primers seated in empty cases, the dent appears to be fine.
    Tests this coming weekend will prove the overall useability of the changes, but I expect everything to be fine as many people who have used this kit report excellent function after hundreds of rounds downrange.

    All I can conclude is that anyone needing or wanting a lighter safe pull on a J-Frame revolver should really consider this kit. It is just not right to sell an otherwise perfect revolver for carry and self defense just because the trigger pull is heavy.

    Although I have never had an issue with my stock 11lb 9oz pull with my 638, I am glad I bought 2 kits so I can now do mine. It will only help keep me on target in DA that much better and anything that can help me be more accurate is a plus in my book.

    Hope it helps.
    Last edited: Nov 7, 2012
  2. Clutch Cargo

    Clutch Cargo Amsterdam Haze

    Likes Received:
    Nov 29, 2010
    Excellent report! Thank you.