Marlin 39A hammer spring

[Petrol & Powder]

I just acquired a Marlin 39A from a family member and it's a great rifle. Despite it's age (late 1950's ?) it is in great shape. My one small issue is the trigger pull which is a bit heavy. After disassembling the rifle, it appears that the heavy hammer spring is the chief culprit for the bad trigger. The trigger return spring doesn't seem to add much weight to the pull but that hammer spring could hold up the back of my truck. The engagement between the trigger and the hammer is good and the sear nose appears to be cut properly. (the trigger doesn't cam the hammer back before releasing the hammer) I don't wish to permanently modify the gun due to its heritage but I could swap out the hammer spring and maintain the original spring in case I wanted to return it to stock.

Has anyone ever experimented with lighter hammer springs on a 39A?

[dubber123]

I would try a light stoning of the hammer notch first, as I really don't like light springs and the lazy hammer falls they create. Marlin ground a "hook" accidentally on some of their hammers, and springs don't help much. I just bought a 1947 336, and the trigger pull was off the scale, literally, Possibly in the 15+ pound range. I stoned the sear to get rid of the "hook", and it dropped to 3# and change without even doing a "real" trigger job. You can push as hard as you want, and it won't fall. 2# on a Marlin with full power springs is not hard to do at all. Sorry I can't help on how much a softer spring might help.

[Petrol & Powder]

10-4 on engagement issues, I've seen sear notches cut so poorly that when you pulled the trigger the sear had to force the hammer back further against the hammer spring before the hammer would fall. I did stone the hammer notch a little but it was in pretty good shape to start. There is so much pressure on that sear that no matter how clean the notch is, there's just a lot of friction.
Too light on the hammer spring = increased lock time and light primer strikes. Too much = heavy trigger pull.

I will say this, the steel used to make that old Marlin hammer and trigger must have been good stuff because despite all of that friction and pressure over the years; that sear still WORKS !

[dubber123]

A Marlin trigger job consists of making sure there isn't a "hook" on the hammer, and stoning it. Part 2 is stoning the sear smooth, and cutting it back on a 45 degree angle. It's hard to describe, but if you look at the relationship of the parts, you will see what I mean. Doing so keeps the sear out on the edge of the hammer notch, but reduces the actual contact point by a significant amount. I have quite a few Marlins, and have done many more. I set all mine to 2.5# for consistency, but you can go lighter. All with factory parts, so it's free except your labor.

[W.R.Buchanan]

[smilie=w: I am sorry but the Marlin Trigger job consists of a $12 Spring Kit from Brownell's. No stoning is necessary as a gun from the 1950's has probably been shot at least 100 times and the sear engagement is probably really nice on it's own.

Messing with sear engagement is something that is best not done unless you know exactly what you are doing. Indiscriminant stoning of piece parts you don't fully understand may lead to and unsafe trigger, or worse yet,,, trashed parts. And in your case with a 1950 gun those parts aren't going to be that easy to replace.

A lighter hammer spring will solve your problem and will take all of 5 minutes to replace, and it is easily reversible. I'm really big on reversible.

I have done a bunch of these guns and used this kit on all of them,,, it also works on 1894's 95's 336's etc.

I have never messed with the sear engagement on any of the guns I have done, simply because it is not necessary, you'll get everything you need from the spring kit, which also includes the lever detent spring, which makes the lever easier to open.

No need to overthink this. :mrgreen:

Randy

[Petrol & Powder]

Is the Brownells kit the same thing as a Wolff spring? And if so, what weight?

[dubber123]

Wait until you get one with a "hook" ground in, and a spring light enough to barely make the parts engage still results in a 10# pull. They exist. I fixed one for a friend, and just bought one. My 1947 336 being the latest. Sometimes it really isn't that easy. I also have my doubts as to whether a simple spring swap will result in a crisp pull every time. Sometimes maybe, but after seeing how poorly some of these sears are cut, I doubt it. Poorly cut sears and light springs make for long creepy pulls, not OK by me.

My 1894P, bought new by me had 1/4 of it's engagement surface missing on the sear right from the factory, apparently chipped off. Marlins QC has never been top notch, and I am a fan of them. If a spring swap works for you, that is indeed great. It doesn't work so well for me.

[Petrol & Powder]

dubber123, I hear you and agree with you. I'm just reluctant to start doing things to this particular rifle that I can't un-do.

The best of both worlds would be a perfect engagement between the sear (part of the trigger on this gun) and the hammer notch. No excessive over travel and well polished surfaces would also be desirable. Add a hammer spring that's not over weight to compensate for the poor factory machining of said trigger & hammer - and you get a good, safe trigger.

What I have seems to be too much engagement + too much hammer spring weight. The notch on the hammer is clearly deeper than width of the sear but the angles appear to be good and the surfaces smooth (no doubt from decades of use with that monster hammer spring pushing on it!)

I'm OK with taking a little metal off the hammer to reduce the depth of that notch, within reason. But I'm still stuck with that hammer spring made by Mack trucks.

I think Marlin made a hammer/trigger that was safe and relatively inexpensive to fit. They then compensated for the poor fitting of the hammer & trigger by using a very heavy hammer spring. If you've ever worked on a Ruger GP-100 you understand that design philosophy :-?

The spring replacement is reversible and if it doesn't do the trick, I can always go back and fix the hammer notch.

[dubber123]

I totally agree, and screwing up hard to find parts is not fun, and best avoided. Reducing the hammer notch is tricky, and I have never had to do that. Doing so runs the risk of the sear catching the safety notch on the way down. The back bevel trick on the sear helps by reducing the surface area you have to drag across to release the sear. By all means, try the spring, if it works, you are in business. You do have the option as you say to fix any factory goofs after if it proves unacceptable to you.

In the same vein, many guys tell you just flipping the leg off the trigger return on a Ruger revolver will fix the trigger. Maybe. It will lighten the pull, but it will also make it a creepy mess if the sear is cut poorly. I've done a dozen or better, and that trick worked exactly once.. :)

Btw, I'd love to have an old model 39, it's on my list. Good luck with yours.

[Petrol & Powder]

Thanks, That 39A was actually the first gun I ever shot.
I forgot about the half cock notch and you're right about that. Thanks for the input.

[W.R.Buchanan]

P&P: Here is the kit from Brownell's, The part#,,, is 080-000-192,,, and as you can see it works for all Marlin Lever Action guns.

Try this first and if it isn't enough then think about going into the engagement.

You also have to ask yourself exactly "How Good a Trigger" do you actually expect from a generic lever gun, and a .22 at that. For what it will be used for you can get used to just about any trigger.

Sure it can be made crisp and perfect but unless you have a jig to mount the hammer and sear in to stone them, I can almost guarantee that doing it by hand will not achieve the results you are looking for.

I not saying it can't be done, I'm saying it is not very easy to do.


I would be willing to bet that the spring kit will make it much better than what you've got now.

Randy

[Petrol & Powder]

Thanks Randy.

[OverMax]

Yep I agree. Replace its springs only and accept what you get. Easyiest and most efficent way to resolve trigger behaviour.

[Petrol & Powder]

I ordered the reduced power spring. Report to follow.

[dubber123]

I hope it fixes your problem to a level that makes you happy. I have only ever worked on 1894's and 336's, never a 39. Unless they are built markedly different than those, a crisp trigger with no detectable movement before release is indeed possible with all factory parts and springs. I set all mine to 2.5#, but the gentleman here on the forum who showed me how to do them has his competition 336 set to 1.5# with all factory stuff, and it has remained that way for years now. I have never gone that light personally though, as all mine are just hunting/general purpose guns.

[Petrol & Powder]

The reduced power hammer spring is now installed in the 39A. The trigger pull is noticeably improved !

[dubber123]

That is good, is is acceptable? The big question is, does it still go bang..:)

[Petrol & Powder]

I shot several rounds into a bullet trap but only used one brand of ammo (old Winchester). They all functioned perfectly. I'll try some different brands later but I don't anticipate problems. The hammer fall seemed to be crisp and the action on that particular rifle is very smooth from years of use. I did use a little gunslick grease on the sear/hammer notch, I might try a little bit of white lithium grease next time I clean it. Probably not much different but lubriplate is easier to come by.
I don't know what the weight of the factory spring is, but it is far heavier than it needs to be.



Thanks for all of the help!

[W.R.Buchanan]

P&P Good to hear you had success.

Randy

[Petrol & Powder]

I gave the 39A a decent workout today and I was very pleased with it!
Old .22 rifles are just plain fun! Got the elevation on the rear sight pretty close to where it needs to be. I had the classic, "too high on one notch and too low on the next notch down". I'll play with different brands of ammo before I take a file to the sight elevator but that's a cheap part regardless of the outcome.

[dgslyr]

They don't teach "replace the springs for trigger jobs " in any gunsmith school.It takes less then 30 minutes to do the trigger on a 39 A.That includes disassembly , stoning ,assembly and trigger pull gauge ,bend the trigger block spring somewhat,repeat until you get what you want that is safe.
Gunsmiths charge for the knowledge you can get for free on Marlin owners.
I just got a Marlin 1894 CB that had a "professional action job".It misfired often.The lever would not stay closed.The trigger block spring had been bent to the point that the trigger block was disabled.(think Chuck Connors in the Rifleman)The hammer block safety had been disabled.I replaced the hammer spring,the lever latch spring and the plunger,and the trigger block safety spring.The trigger pull with factory springs is 2 3/4 lbs.

[Dave Bulla]

First off, glad to hear you are happy with your results after the spring change. I personally am not a fan of the reduced power spring kits. They do make the action easier to cycle but I've had issues with fail to fire on the one rifle I own that has a spring kit.

I am instead a big fan of doing my own trigger job. There are two options really. Actually three if you count a "Happy trigger kit" but I don't as they are about $90 and I can do a better job myself for free. The first way to fix it yourself is to carefully bend the trigger return spring to reduce its tension. This can reduce the pull a couple pounds but does not do anything to smooth it out. The second and the one I prefer is to stone the trigger sear. The simple version of this is to reduce the backset angle of the sear by about 50% and ensure it is square, even and sharp. I'm not talking about the notch on the hammer (though I do inspect that and give ita couple strokes with a stone if needed) but rather the trigger sear. Marlin center fires have a two piece trigger so the actual sear is a separate piece, the 39A has a one piece trigger so the sear is on the tip. I usually avoid files as they will chatter over such a small surface. I have a set of knife edged (triangle cross section) hard Arkansas stones and some 1/4"square by 4"ones. A good magnifier is a big help too. I've used a 10x jewelers loupe with good results. There is a thread over on Marlin owners with real good instructions. I'll see if I can post a link for you. Not a hard job in my mind but some people are intimidated by the thought of modifying their triggers so are not comfortable even attempting it. Me, I've been a mechanic all my life so I'm pretty comfortable with such work and I've done all my marlins with fantastic results. All are safe, pass any bump check you can come up with and now have trigger pulls better than most bolt action rifles. I can do one now in about an hour with no hurry. Probably half that if I really tried. The first couple took about twice that long. Not a job you want to get in a hurry on anyway so no point in even trying to be fast at it. just do it well and let it take as long as it takes.

[Dave Bulla]

Here's my preferred method:

http://www.marlinowners.com/forum/basic-triggers/72679-sear-fix-lighten-trigger-pull.html

And another showing how to bend the trigger return spring. Just so happens to be on a 39A Mountie too.

http://www.marlinowners.com/forum/basic-triggers/33129-marlin-trigger.html

And some basic safety checks.

http://www.marlinowners.com/forum/basic-triggers/64679-basic-trigger-safety-tests-bump-test-push-off-test.html

Hope this helps.

[Sneakybuffalo]

Nvm, by the time I read Dave's big ole paragraph he had posted the links :P

[Petrol & Powder]

Dave Bulla - thank you for the advice. I am comfortable with stoning a sear and hammer and have done so when it is a prudent thing to do. On the 39A, the tip of the trigger is the sear. I did stone the hammer notch and the tip of the trigger on my 39A but it was pretty good to start with. Less is more when you're playing with some mechanical interfaces and I didn't want to get too drastic with the stoning.

I've seen hammers so poorly cut that when you pulled the trigger, the hammer would have to be cammed back by the sear before it was released. That condition makes for a very heavy trigger pull because you must first overcome the mainspring before the sear releases the hammer.

This particular rifle means a lot to me but I was able to improve it considerably with some light stoning and a new mainspring.

I totally agree that a light mainspring can cause light hammer strikes but in this situation there seems to be more than enough energy to get reliable ignition.

Thanks to all for the insight and suggestions. This is a great forum.