Mcarbo trigger kit from the US

[Hamster]

Well today I tested the gun again and still no cigar ?  it does fire the first round but won't do so again until the new (correctly fed round) is manually cycled out whereupon a dent appears to indicate hammer bounce ?! The trigger itself is almost ludicrously good for a semi auto but clearly something is not right. Incredibly Mcarbo have sent me several e-mail asking how the installation went and I have just sent them this reply today hoping for some feedback : 

"Hi, Chris,

 

I just want to let you know what happened after I re-installed the trigger unit for my Remington 597 and proceeded to test it with live ammo. The first 2 magazines did fire and cycle almost but not 100% without fault but unfortunately the gun then began to fire a single round and fail to cock the trigger for the subsequent round. The unusual thing is that the next round IS feeding into the chamber but the gun won't fire without THAT round being manually ejected whereupon only the next round will fire, examination of the ejected bullets show they appear to have received a mild dent which seems to indicate some kind of hammer bounce ?!

 

Unfortunately not being a trained gunsmith my understanding and grasp of the firing cycle is not as good as some but I am going to experiment by swapping the new (lighter) spring back for the old one whilst retaining the new lighter hammer and then depending on results may have to try the reverse, presently as fantastic as the actual trigger pull is the guns near flawless function with the old trigger has been compromised. I would appreciate any tips or clues and please understand that this is not in any way a criticism of your product as I am experienced enough to know the reasons could be many and varied including some kind of user installation error and/or something having been misaligned by my opening the action etc,.

 

Regards, "

 

Before I re-open the guts and have another go if anyone here can suggest anything I'd be grateful.

[Jimiles]

Hi Hamster...have you previously done anything at all to your sear spring?

My kit arrived yesterday morning and I was off to the shed to get it installed. Had it fitted in minutes and everything seemed to be going flawlessly...and then the nightmare began.

Before I go into detail I will explain that I have already modified my rifle following a tip I found on the Rimfirecentral forum. This involved drilling and tapping a hole through the trigger guard and up beneath the sear spring. An Allen screw could then be fitted and the theory was that adjusting that screw would adjust the pull off. The sear spring itself was also replaced with a slightly lighter spring. Having completed this I found that I could indeed adjust the trigger pressure however it introduced a catalogue of issues - the safety catch not moving over to safe, double taps, and also the same problem as you have described with the light strike. Increasing the pressure again with the adjusting screw rectified all of these but obviously put the trigger pressure back up pretty much to where it was previously. However, it worked, so I lived with it as it was.

Having fitted my new spring & hammer yesterday I was horrified to find all of the above problems were back. Even worse was hearing the rifle fire on a snap cap when I lightly patted the stock with my hand. I must have stripped down & reassembled that trigger mech 20 times yesterday and I ended up having to put my original modification back to the factory condition. This entailed removing my Allen screw and refilling the seat for the sear spring with epoxy resin for the spring to sit on. Even this didn't return it to correct operation and I had to replace my weaker sear spring with the original heavy factory spring. It then became apparent that even the height of the well on which the sear spring sits is critical and I had to remove tiny amounts of epoxy  resin to get the balance just right. I only finished working on the rifle late yesterday evening and a quick magazine of 10 confirmed it was all okay again. When the rain stops I'll get out and put a few more rounds through it just to make sure but I must say I am now very impressed with the clean, light trigger release. I'm sorry this is all so complicated to relate and I hope gives you a few pointers to consider. Jim

[Hamster]

1 hour ago, Jimiles said:

Hi Hamster...have you previously done anything at all to your sear spring?

My kit arrived yesterday morning and I was off to the shed to get it installed. Had it fitted in minutes and everything seemed to be going flawlessly...and then the nightmare began.

Before I go into detail I will explain that I have already modified my rifle following a tip I found on the Rimfirecentral forum. This involved drilling and tapping a hole through the trigger guard and up beneath the sear spring. An Allen screw could then be fitted and the theory was that adjusting that screw would adjust the pull off. The sear spring itself was also replaced with a slightly lighter spring. Having completed this I found that I could indeed adjust the trigger pressure however it introduced a catalogue of issues - the safety catch not moving over to safe, double taps, and also the same problem as you have described with the light strike. Increasing the pressure again with the adjusting screw rectified all of these but obviously put the trigger pressure back up pretty much to where it was previously. However, it worked, so I lived with it as it was.

Having fitted my new spring & hammer yesterday I was horrified to find all of the above problems were back. Even worse was hearing the rifle fire on a snap cap when I lightly patted the stock with my hand. I must have stripped down & reassembled that trigger mech 20 times yesterday and I ended up having to put my original modification back to the factory condition. This entailed removing my Allen screw and refilling the seat for the sear spring with epoxy resin for the spring to sit on. Even this didn't return it to correct operation and I had to replace my weaker sear spring with the original heavy factory spring. It then became apparent that even the height of the well on which the sear spring sits is critical and I had to remove tiny amounts of epoxy  resin to get the balance just right. I only finished working on the rifle late yesterday evening and a quick magazine of 10 confirmed it was all okay again. When the rain stops I'll get out and put a few more rounds through it just to make sure but I must say I am now very impressed with the clean, light trigger release. I'm sorry this is all so complicated to relate and I hope gives you a few pointers to consider. Jim

Hi Jim,

When I first got the rifle I read up on tips to make it less bullet fussy by polishing the steel springs rods (that the firing pin housing moves along), including a tip to make sure the screws holding these in aren't made too tight etc, I gave a small list of these to my gunsmith who must have done a decent job of carrying them out. The reason being that previously the gun didn't digest Winchester subs at all well but went on to fire these almost as well as the CCI's which it fed well on before. I can't recall if I asked him to do anything to the trigger but I doubt anything has/had been done to the sear spring itself, I've personally never even touched it. 

Do I understand that you have now put back your entire old trigger unit back in ? Did you experiment at all to see whether the new lighter hammer on its own would be any good ? It would be a shame if I couldn't get it at least half way decent because as previously mentioned I think this would make a good rifle into a great one. 

ps. just in case it wasn't clear from my original description, the mild dent I am referring to occurs WITHOUT me pulling the trigger a second time, in other words the gun fires one bullet only and once the already fed but unfired round is manually cycled out it reveals the said dent despite the trigger/hammer not having fallen onto it meaning some kind of hammer bounce is causing these. 

Edited August 21, 2018 by Hamster

[Jimiles]

I'm sorry, I've re-read my post and perhaps I should clarify that I did install the complete new mod kit - the hammer, spring & bushes. That kit is still in the weapon and I was determined to make it all work with that kit installed and that is what I have now achieved.

I do not think your 'light strike' is a strike at all. I think what is happening is that after firing a shot your working parts cycle back as they should and pushing the hammer back to the cocked position. The working parts then go forward chambering a new round. At the same time the sear should have ridden up to retain the hammer in the cocked position. The hammer should then remain there until the trigger is pulled again but in your case I do not think the sear is engaging the hammer properly and the hammer is floowing the working parts forward again. As the working parts slam shut the hammer rotates into contact with the back of the firing pin and pushes it forward enough to give a light strike. This doesn't happen when you manually cock the action to chamber a round because this process is very much slower than when the action cycles after firing - when you cock it by hand the sear has enough time to engage, when the action cycles after firing the sear does not have time to engage properly. I'd suggest that this is potentially a very dangerous situation where you might have the weapon fire without warning, as I said...mine fired when I struck the stock with my hand. The plus side of my frustrating day yesterday is that I really got to know the workings of my rifle and I found that the sear spring affected everything and has to be right. I suspect somebody has lightened your sear spring at some point. Doing this on its own would be fine and probably did work to reduce the trigger pull however fitting the modoified hammer/spring has just tipped it over the edge. I would perhaps speak with your gunsmith and ask if he did anything with the sear spring. I suspect fitting a new sear spring would resolve your problem - I certainly hope so!

Jim 

[Hamster]

49 minutes ago, Jimiles said:

I'm sorry, I've re-read my post and perhaps I should clarify that I did install the complete new mod kit - the hammer, spring & bushes. That kit is still in the weapon and I was determined to make it all work with that kit installed and that is what I have now achieved.

I do not think your 'light strike' is a strike at all. I think what is happening is that after firing a shot your working parts cycle back as they should and pushing the hammer back to the cocked position. The working parts then go forward chambering a new round. At the same time the sear should have ridden up to retain the hammer in the cocked position. The hammer should then remain there until the trigger is pulled again but in your case I do not think the sear is engaging the hammer properly and the hammer is floowing the working parts forward again. As the working parts slam shut the hammer rotates into contact with the back of the firing pin and pushes it forward enough to give a light strike. This doesn't happen when you manually cock the action to chamber a round because this process is very much slower than when the action cycles after firing - when you cock it by hand the sear has enough time to engage, when the action cycles after firing the sear does not have time to engage properly. I'd suggest that this is potentially a very dangerous situation where you might have the weapon fire without warning, as I said...mine fired when I struck the stock with my hand. The plus side of my frustrating day yesterday is that I really got to know the workings of my rifle and I found that the sear spring affected everything and has to be right. I suspect somebody has lightened your sear spring at some point. Doing this on its own would be fine and probably did work to reduce the trigger pull however fitting the modoified hammer/spring has just tipped it over the edge. I would perhaps speak with your gunsmith and ask if he did anything with the sear spring. I suspect fitting a new sear spring would resolve your problem - I certainly hope so!

Jim 

? Thanks, will have a good look tomorrow and see. 

[Hamster]

17 hours ago, Jimiles said:

I'm sorry, I've re-read my post and perhaps I should clarify that I did install the complete new mod kit - the hammer, spring & bushes. That kit is still in the weapon and I was determined to make it all work with that kit installed and that is what I have now achieved.

I do not think your 'light strike' is a strike at all. I think what is happening is that after firing a shot your working parts cycle back as they should and pushing the hammer back to the cocked position. The working parts then go forward chambering a new round. At the same time the sear should have ridden up to retain the hammer in the cocked position. The hammer should then remain there until the trigger is pulled again but in your case I do not think the sear is engaging the hammer properly and the hammer is floowing the working parts forward again. As the working parts slam shut the hammer rotates into contact with the back of the firing pin and pushes it forward enough to give a light strike. This doesn't happen when you manually cock the action to chamber a round because this process is very much slower than when the action cycles after firing - when you cock it by hand the sear has enough time to engage, when the action cycles after firing the sear does not have time to engage properly. I'd suggest that this is potentially a very dangerous situation where you might have the weapon fire without warning, as I said...mine fired when I struck the stock with my hand. The plus side of my frustrating day yesterday is that I really got to know the workings of my rifle and I found that the sear spring affected everything and has to be right. I suspect somebody has lightened your sear spring at some point. Doing this on its own would be fine and probably did work to reduce the trigger pull however fitting the modoified hammer/spring has just tipped it over the edge. I would perhaps speak with your gunsmith and ask if he did anything with the sear spring. I suspect fitting a new sear spring would resolve your problem - I certainly hope so!

Jim 

Right then here's the run down :

Old spring with old hammer = heavy pull hence why I started the search for a fix/kit and this is how I am leaving the gun to hand over to my friendly gunsmith if he takes on the challenge, if he doesn't then I will need to seek out a trigger man. I believe you have correctly identified the problem as the hammer failing to retain cock mode.  

Old spring with new hammer = gun barely even holds cock suggesting new spring not much different to old (in performance because they do have slight dimensional differences) and a solid indication that the new hammer is the major factor.

New spring old hammer = holds cock but heavy pull so pointless.

Above are all dry fire mode so I don't know exactly how gun would function. 

I tried to Youtube/google for some help or clues ref the sear spring to no avail and if I'm honest I don't even know whether it's the short fat one to the side of the action or hidden inside the trigger block ! There is a lot of good info out there though including others who seem to have found the mod results in "too light" a trigger. 

[Jimiles]

Probably a wise decision. Assuming it is the same gunsmith who did the polishing job on the guide rails I would ask him if he remembers doing anything at all to the sear spring. It isn't the short fat spring, it is located underneath the sear and is very difficult to see and even worse to strip/assemble. It is actually glued to the base of the trigger mech housing with some sort of silicone adhesive if that helps you to locate it. I have benn back onto the Rimfirecentral forum where i originally found a pictorial guide to this particular modification intending to post the link here but for some reason I cannot now access the forum.

[Hamster]

?

[Jimiles]

If this link works it will show the sear and the round 'well' in which the sear spring is seated. The spring itself is missing.

https://www.google.co.uk/search?q=remington+597+sear+spring&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi6m6j3tIDdAhWKIMAKHfb4B_sQ_AUICygC&biw=1920&bih=966#imgrc=2bniM8z2_u8IkM:

[Hamster]

2 hours ago, Jimiles said:

If this link works it will show the sear and the round 'well' in which the sear spring is seated. The spring itself is missing.

https://www.google.co.uk/search?q=remington+597+sear+spring&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi6m6j3tIDdAhWKIMAKHfb4B_sQ_AUICygC&biw=1920&bih=966#imgrc=2bniM8z2_u8IkM:

Perfect, that looks very clear. I have now been and spoken to my gunsmith who suggested we first order a new sear spring to make certain we're starting from ground zero. This may prove harder than it sounds as initial internet searches in the shop seems to indicate that this item doesn't appear on Remington spares suppliers itineraries ?  so I may well have to try and get one from the states unless anyone can help ?

What did transpire from our chat is that he seems to believe that the sear engagement of the new kit is too fine which doesn't allow it to bite enough on the way back, (exactly as per your prognosis), the good news is that he appears to feel confident in being able to cut microscopic chunks out of this section in order to raise the "break" point to somewhere closer to 3 lbs which I would prefer for a hunting gun anyway. 

How odd that such a kit has found its way onto the American market when it's seemingly so close to being a hair trigger. ? 

[Hamster]

Latest e-mail from Mcarbo, at least we now know there IS a problem : 

"Good morning,

Thank you for letting me know of you problems. It has come to our attention that some customers are experiencing an issue with the M*CARBO Remington 597 Pro A2 Hammer in certain 597 models. Our team is working hard at releasing a revised design. We pride ourselves in making quality parts and outstanding customer service so send us an email if you have any further questions. If your experiencing any issues please discontinue use of the MCARBO hammer. Thank you for you support and understanding. If you could provide me with your full contact info, I will add you to a list, to ensure that receive a replacement as soon as it is available. 


Your emails are important to me and I will respond as quickly as I can, however, please allow 24-36 hours for me to respond.  If you do not receive a response within that time or if it is urgent, please call the office at 888-347-1276.

How would you rate my service or your experience with M*CARBO?
Great    Okay    Not Good

Thank you,"
 

[Jimiles]

That's a bit of a worry. I would consider my trigger to be safe but I've got to say it is very light...and I don't have a trigger tester.

[Hamster]

3 minutes ago, Jimiles said:

That's a bit of a worry. I would consider my trigger to be safe but I've got to say it is very light...and I don't have a trigger tester.

I have a fair bit of air gun mileage behind me so can usually tell one that's around 5-6 or 3 or 1, obviously not infallible without a gauge but if yours needs a deliberate pull then it won't be unsafe, I may have kept it as it was had the gun functioned correctly but was kinda relieved to find it didn't because initial dry firing had felt very light for a powder gun. 

[Hamster]

Out of the blue I've received an e-mail from Mcarbo telling me "my item" has been shipped, presumably this is the replacement their team has been working on. Meanwhile my gunsmith managed to tune the poundage to 3/1-4 pounds using the new hammer and the old springs, gun functions flawlessly as before but if I'm honest I'd have wanted it a touch lighter which he has already said he will try again but now I think I'll wait and see what happens with the new offering. 

[Scully]

An engineer mate of mine ‘polished’ the sear of his brand spanking new H&K 9mm back in the days when we were allowed such things and turned a self loading pistol into full auto! In the process he made it entirely illegal and invalidated the warranty! Good to watch though. 😃

[Hamster]

On 22/08/2018 at 18:04, Jimiles said:

That's a bit of a worry. I would consider my trigger to be safe but I've got to say it is very light...and I don't have a trigger tester.

I have now received and fitted the new replacement/revised hammer with a note saying the shims should only be used with their own spring, presumably meaning they are not compatible with the factory spring. 

In dryfire mode it feels half way between the original really light (which proved un-useable as it wouldn't cock) original replacement and the 3-1/4 lbs pull my gunsmith managed to tweak it to. If I had to guess I would say it feels just over 2 lbs, if you haven't got one sent to you it might be worth sending them an e-mail. 

[Jimiles]

Thanks Hamster, mine arrived yesterday and was fitted within a couple of minutes. I took the rifle up onto the hill and 20 rounds functioned flawlessly. I still cannot weigh the trigger pull however to me it 'feels right' so I am happy!

[Hamster]

On 02/10/2018 at 14:16, Jimiles said:

Thanks Hamster, mine arrived yesterday and was fitted within a couple of minutes. I took the rifle up onto the hill and 20 rounds functioned flawlessly. I still cannot weigh the trigger pull however to me it 'feels right' so I am happy!

Nightmare first outing with the revised hammer which I'd fitted together with Mcarbo's own new spring, basically the rounds get struck but won't go off every time, you get better (or worse) odds with Russian roulette 😁  as roughly one in 10 pulls results in the bullet being fired. It had to happen on the one day when every crow within 200 yards was decoying a treat as well, absolutely surreal as I had to keep manually cycling the bolt, catch the struck round and keep pulling the trigger until one would go off. When the gun did fire the next round would feed flawlessly but of course the chances of it firing were, well one in ten ! I managed to kill two that let me have five "shots". 

Totally ruined what should/could easily have been my best crow/rimfire day. I have now fitted the factory spring and the original (fettled) Mcarbo hammer back in the gun because I know they work, might re-try the new hammer with the factory spring at some point in the future.