Home Forums Hunting & Shooting Savage Collectors Learning about trigger, sear, springs, interfacing surfaces

I reworked a trigger today by applying a theory I broached a while back. Of course, this is always a popular topic.

Relax, I'm screwing around with a junk parts gun just for the sake of better understanding the workings of the 1899. I'm putting myself thru Savage university by playing with the various parts and their interaction. Beats sitting in the house watching Cinderella, (literally).

Do not take this as any kind of endorsement to screw with your gun. I am afforded the luxury of having a junker to play with, so no loss if I ruin a $20 part and have to replace it, which I would in a heartbeat if I ruined anything. That said, check this out.


I had a damaged but functional sear for an 1899 so I rounded it off where it mates with the firing pin sliding surface. Now instead of two flat surfaces making contact and sliding off each other when the trigger is pulled, I removed two thirds of the width of the sear mating surface by rounding the corners off and polished the remaining 1/3 with fine emery cloth.

I also shortened the sear a little to shorten trigger travel, which was horrendously long.The mating surface on the firing pin remains unchanged as no advantage can be gained there and potential problems abound by modifying that.

Once sear and bolt are installed and gun is cocked, and with the stock off, I pounded on the tang using a wood mallet to try to get a slamfire. None. End of barrel, none. Wailed on it harder than you ever would by dropping it. No slamfire. In fact, the trigger and sear remained stationary with no movement at all toward a slamfire. Who knows, the next rifle you try it on may slamfire with little effort, but this one won't. Every rifle is individual that's why you should not try this with yours. Did I mention do not try this with yours?

By reducing the width of and polishing the sear with fine emery cloth, as well as shortening it, the trigger travel was reduced to a reasonable distance, more in line with other Savages I own, and while the trigger pull is very heavy, it is very smooth. It seems as though the trigger weight is mostly a function of the firing pin springs resistance rather than the trigger spring. The trigger spring just holds the trigger in the forward position more than anything.

Reducing trigger pull weight is a conundrum. If you reduce tension on the firing pin spring by clipping coils you'd risk light strikes on the firing pin primer. Does not seem a reliable solution and also perhaps fraught with peril. But, I may try it just because that's how my mind answers these questions. I have only the cost of parts and a little time to lose. Please don't misread this as an endorsement to attempt this. I'm just throwing it out there as an academic exercise. Honestly, I don't think most people have the aptitude or patience for this type of thing. I happen to enjoy learning things like this, but it's not for everyone and it does cost money and take time, as well as clutter a large area in the shop.

Hopefully I will not be tarred and feathered and runnoft.

Interesting and I’ll leave that feathering and tar thing to someone else. I may also make a comment but that will have to wait until after having a cup of inspiration tomorrow morning.

I have a chicken farm nearby that has an endless supply of feathers, and I prefer to use wood glue instead of hot tar (there's no need to cause Roy cruel or unusual pain, just the public shaming is enough).

But, all seriousness aside, I freely admit to being a 99 hobbyist/amateur tinkerer, and claim as much whenever I sell a rifle or parts, if I've dinked with it, (Thanks Larry Potterfield!). So, I appreciate Roy's exploration, and full disclaimer, of a subject near and dear to us all.

Are we forgetting the role real gunsmiths here? Those trained, experienced, and licensed 'smiths hold a great deal of collected wisdom. I think a good follow-through for this sort of discussion would be to have a licensed gunsmith examine Roy's work, and possibly even certify it.

That still doesn't make Roy's work universally acceptable, but we often field the question of "finding a qualified 99 gunsmith". We might be able to contribute to the greater good, by learning more about 99s then passing it on.

The first question that popped into my head was what might happen down the road 10, 20, 30 years later after significant/hard use. Will the newly configured assembly wear "properly" and not in a manner that induces a slam fire?

Were the sear surfaces made of high quality tool steel and through-hardened or were they made of lesser steel and merely given a good thick case hardening? That would have a bearing on how much meat can be removed- again with long term use wearing through the remaining structure more rapidly than normal if indeed we're talking case hardening, leading to Roy's tar and feathering (albeit by our grandchildren going after his grandkids).

So, were you the guy who runnoft with Mrs. Hogwaller?

Roy, I have run into maybe a half dozen lever safety guns with trigger/sear mods that made them unsafe. One thing most of these had in common is that during the cycle of closing the lever the sear engagement was reduced to mere thousandths of an inch. There is much greater sear engagement when the lever if fully closed. Watch this engagement as you close the lever and see if you observe what I did.

I applaud your experiment. I would just admonish you to not put the gun in other hands without restoring it with factory original parts.

I'm having trouble loading photos for some reason. I'll keep working on it.

As for wear, the center remaining 1/3 of the sear is polished only and otherwise untouched, so whatever hardening was there is still there. I don't personally believe wear is going to be an issue. "hard use"? Not sure how you use a trigger harder at one time or another, although an undue accumulation of dirt would qualify. Looking at sears I've never seen any evidence of any wear on even the oldest ones. I don't think it's a high wear piece.

Hogwallop. She was hot. We done runnoft.

I always appreciate Roy’s willingness to “take a look under the hood.” My general observations have been that earlier 99s (say those built prior to WWII) have quicker triggers than later 99s. That is later 99s have much more creep. I don’t know about the rest of you guys but I’ve heard stories of 99s back in the day having a bit of a slam fire reputation that would happen if the butt took a strong hit. Granted all it takes is one bad occurrence to make a reputation. But I also figured that the creep added to the 99 trigger mechanism was a response to that problem, I.e., more surface contact area made for a more positive lock up.

I am unclear on one point. When you say you reduced the contact area by rounding off the corners did you mean the corners as if you were looking straight down on the the sear? My only concern with that is it could add some sideways movement to the mechanism that was never part of the original design and that may cause some issues elsewhere.

Mike, if I can get photos to load I'll show you what I have for sear engagement. We're not in dangerous country at all, just normal.

This is entirely a parts gun, no two parts from the same weapon, so it had an extremely long trigger travel with this combination. As you know when you start combining parts they sometimes have to be made to work together. Fitting the extractor is an example. Nothing wrong with fitting an extractor, it's part and parcel for the work at hand. This sear shortening was much the same. It was entirely too long creating excessive trigger travel, thus the need to shorten to a length giving function similar to the other guns here.

The separate task of rounding the sear is the bigger, more experimental issue. Although honestly, it's pretty simple machinery we're talking about here. There's no side to side wobble so the sear's not falling off the firing pin interface. No slamfire due to sharp blows, that's been proven with the wooden mallet.

Gnoahhhs concern with hardening and wear seems the most legit concern, one I had thought of and am mindfull of. But if you think about the wear created when two parts slide off one another, it would be perpendicular to the surfaces, "straight in" to one another. That type of wear would not create a more dangerous situation. If anything they would "mate" as they wear together, creating more bearing surface as they wear in. The exception to this would be where they disengage and all the firing pin spring tension slides off the point of the sear. That might be where the sear engagement could be left full width for wear resistance.

If this connection made cycles like a commercial sewing machine in a Thailand sweatshop I would worry more about *wear* and bearing surface. As it is, I'm not all lathered up about the number of trigger cycles a gun sees in it's lifetime.

Wish I could get my dang photos to work today...

So the metal I removed from the sear is on the actual mating surface with the rear of the firing pin, the "bulbous" interfacing piece of the firing pin remains unchanged. Now instead of the sear being about 1/8" wide contact area with the firing pin, it is 1/3 that. As mentioned, length of engagement was also reduced, not from "normal" to too short, but from too long to normal. I still have plenty of length of engagement. To include that information may muddy the waters for some, but don't let it, that's not really the topic.

So the sear is now sliding on 1/3 the surface area it was, as it is now three-sided rather than flat faced.

Side to side movement is controlled by the other end of the sear where the pin goes thru it. Remember me mentioning I had a damaged sear to start with? This is where it's damaged. This sear is actually missing a chunk of the metal that helps stabilize side to side movement. That's specifically why I chose to modify this one. It's got some built in "worse case scenario" with it's reduced side to side control, and yet it still works perfectly. An undamaged sear would be even better, so this seemed like a good choice to experiment with.

I think I get it. Thanks. Maybe the next thing to do is to assemble it into a beater and subject it to the beat test.

I did beat on it good and hard. I'm not done, when I get a minute I'll be back out there.

I mean the field beat test. Load it up and drag it out to the range with a pile of cheap ammo, given you can find any cheap stuff.

Still have some work to do before it's a shooter.

I had to drop my EG serial #5xxxxx about 10' when a tree stand step fell off leaving me hanging by one hand. I needed both hands free so I could wrap both arms around the tree and slid down to the next step. The safety slid off and the lever popped open but it didn't fire. I was about 15 or 16 at the time so that is one of several reasons I'm lucky to still be around. It might have shot me off of the tree if it had gone off or at least scared the s**t out of me. Literally !

Crappy photos-

So how does the trigger pull feel? My experience with post war 99s is that there is an amount of creep to get through as the two surfaces slide past each other. Sometimes there’s some stageyness also involved which I always figured had to do with less than perfect surfaces mating between the hammer and sear. Do you notice any less of these issues and/or is the pull any lighter? Pardon me if I missed this somewhere in your comments but I’m being lazy and trying to keep the topic going.

Before the mods, the trigger pull was very long, had "chatter" from machine marks on the sear, and had lots of hesitation and hangups.

It's shorter now, slick as snot no chatter but still very heavy. Completely happy with it One slip and gone. The weight is all I need to address at this point.

Not sure what you could do about weight short of clipping a coil on a spring. What do ya have in mind?

It would be interesting comparing your mod to another 99 that just had the mating surfaces polished.

That's all there is. Unless someone knows something about changing the composition of spring steel!

I'm with you so far. You might be onto something.

I wonder how much a fella can get away with in terms of clipping coils off the mainspring to lighten the pull without increasing lock time noticeably, and still get reliable ignition even in cold weather.

Considering how hard it is to compress that dadgum firing pin spring by hand and get a pin thru the firing pin to hold it I believe I could safely take a coil or two and try it.

For me a better comparison would be a before/after of the same weapon. A different weapon introduces an entirely new set of variables.

Roy,
sent you a pm with a link to a post on another forum ref trigger pull. If link does not work, pm me your email and I'll send a pdf print of it.

Gary might. He’s the science guru on stuff like this. You two should team up on 99 “method and theory.”!

You could do that but it might get a bit tedious pulling and replacing parts for an A B comparison. I think it might be good enough polishing the trigger on one of your other 99s for purposes of comparison, unless you’ve seen a lot of variability in how 99s were manufactured.

Variability in the parts is the fox in the hen house! These rifles were made in an era where parts interchangeability was just a dream.

It takes zero time to drop the bolt, remove the cross bolt that holds the sear and drop another one in. It would be a good experiment. I'll work on that when I get time.

Well then very cool!

Did you perchance measure trigger pull weight before starting the experiment? If you get around to measuring pull weight how about measuring it when dry and also well lubed.

I have wondered about the junction of the sear and trigger. Some triggers have an oval hole in which the sear pin rides, others are a simple open ended slot. Either way it's a basic camming action that happens in there when you pull the trigger. Polishing those surfaces might reduce pull weight a skinch too (but obviously do nothing about creep). I think by the very nature of the Savage system, creep is inevitable, and a necessity for safety. Like you said (I think) the trick is to reduce creep to the point where it isn't so annoying yet still plenty safe.*

Getting back to beveling the sear surface. I wonder if it'll wear more rapidly now that there's only 30% of the original surface bearing on the hammer. What am I saying, of course it'll wear more rapidly. The question is how fast will it wear and does that really matter? Dunno.

You have me sitting here studying my own naked receiver (1913 1899A) and it occurred to me to bless Arthur Savage for making the whole trigger/sear/hammer system a compound lever design. Can you imagine the gorilla fingers you would need to squeeze off a shot if the trigger was holding back the hammer all by its lonesome?

* Note: I'm not advocating shortening sear engagement. What Roy is doing is skating out close to thin ice and turning back before it's too late. He knows what he's doing and is savvy enough to recognize failure and replace parts before an innocent gets hurt. The Bubbas of this world don't always get it.

X amount of spring force is now applied to 33% of the area as before, so it's bound to wear faster, but enough to notice?

Consider the number of cycles a mechanism like an internal combustion engine does, with the heat generated, the sheer number of rotations, and the force applied to the moving parts. Look how long it can run under those loads before wearing out. I think 20, 200 or even 2000 shots a year on the old 1899 trigger will be workable.

Gary, did I hear you say that the firing system has a camming action that increases the mechanical advantage of the trigger? Geez I hope that question made sense. If so, would there be any way to modify that mechanical advantage, say boost it or make it adjustable. Crap, now I’m going to have to pull a stock!

Also, I guess if wear was an issue you could have the parts hard chromed. Would hard chroming, for lack of a better word, increase the slickness of the sear trigger action? I know my father used to recommend hard chroming John Deere drive shafts as an economical alternative to buying a factory new shaft. We’re talking the big four-wheel drive units from back in the 70s.

No, Jeff, not exactly. The camming action comes from the trigger moving through an arc while pulling the sear down via the pin in the sear. If you watch it while it goes you can see the pin travels (rubs) for about 1/16" on the slot cut in the leading end of the trigger. "Camming" may not be the best term but I can't think of anything else to call it.

Roy, as for wear, I agree it's probably a non-issue. But, if you look at it in terms of 30, 40 50 years down the road then it might. This 106 year old action has been cycled 137,463 times (I counted ), or, well, a helluva lot I'm sure. It shows definite wear on the sear interfaces. Again,a non-issue at this point in time I'm sure. If I were to use this action for a build I would probably only stone the sear interface and call it a day.

I hope to someday wear out a single rifle part. LOL. I'll be having a good time!

Maybe we should all get together with one gun and make it our goal to not stop shooting until we’ve worn out “a single rifle part.” You know, bucket list stuff.

Here's my bit of troubling experience with sear engagement, which might be, ** a risk for Roy's sear modification***; I had an 1899, I don't know the serial number but it had a round-back bolt and a hammer/sear style like Roy's. I replaced the butt stock and rushed off to the range.. I had round #5 discharge while putting the bolt into battery. I couldn't get it to happen on the bench with the butt stock off.

I thought the hammer or sear might be hanging up on the rough wood surface of my rushed inletting work, so I rasped back the inside of the side panels. It must have been dragging somewhere because lever movement got smoother and I could not recreate false hammer trip. Back to the range, and it happened again on round #20.

Turns out that there was some slop (damage? wear?) in the hammer pin, allowing it to rotate on the firing pin a couple degrees. The sear and it's pivot pin also had some slop (wear? or mis-matched parts?), that allowed it to shift off it's left/right vertical. ***The sear was actually slipping off the SIDE of the hammer*** as it cycled into battery.

The solution was replacing the sear and sear pivot pin, removing the barrel and making that receiver into a parts donor paperweight, an someday a lamp.

I believe there is side play in all the hammer,firing pin combinations. I have noticed it in all the savage rifles i have worked on. i would be leary of thinning either the trigger sear or the hammer block very much. not saying it cant be done a bit and improve trigger pull, just use caution.im sure the triggersear would take along time to wear even being thinned. Don

I will check side to side play and see if I can force the sear to slip off the firing pin. Thanks for the input!

I’m not certain side play is going to be an issue with Roy’s mod. As I understand it, he only reduced the amount of interface on one side thus allowing that side of the assembly room for lateral movement against the opposing and factory original sized side. The reduced face may wiggle back and forth but, unless he runs into JeffGs situation, it shouldn’t move any further than the width of the opposing face.

But I have to add that if Roy does run into JeffGs issue, then he’ll get there faster with his modification than he would have if the parts were left alone. All this does make you wonder why Savage in the first place chose the dimensions he did for these parts.

Just checked the side to side play by prying with a screwdriver to try to get parts to disengage either way. Nope.

I thought of the side play thing yesterday because I thought I remembered it in the 1914-vintage action I resurrected a few years ago. Last evening while messing with the current "orphan" (visual aid for following along with Roy's treatise) I couldn't get the parts to move laterally, so I disassembled one of the "good" guns to see if it had that trait, and then the aforementioned 1914 H. No on all accounts. Sorry, I'm not going down the line and checking all of my guys for this!

I can see where it could be an issue though. But, I submit that a savvy Tinkerbelle would be attuned to such situations and either correct the issue or cease and desist with tuning the sear on that particular rifle. Such a problem would be an indicator of other possibly more serious issues than a merely rough trigger pull.

If there were any issues of side movement I’d check to see if it tended to be more in one direction than the other. If so, then Roy’s mid could be offset to the opposing side of the movement. Not that I’m trying to take sides on anything here 🤪

I guess there will always be some unwanted extra movement somewhere in whole system, from trigger finger to tip of firing pin. Manufacturing tolerances (and wear) being what they are. Actually, when looking at it I'm again impressed with the ingenuity involved with tripping the hammer with a trigger mounted so far away. Kind of Rube Goldberg yet efficient. Art was no dummy.

Yeah, it certainly is a lot different than a Winchester or Marlin. The 99 has always looked like a complicated falling block action to me.

Back to the firing pin spring...

Does anyone know if primer metal has changed since 1900 so would require less pounds force to fire a primer? Just wondering if the force to fire a round produced in 1900 differs from a round made now ( WWII or 1960)? Or, if priming material is easier to ignite?

Good question

Roy, try what I sent you before cutting coils.

If you remove the bolt and pull the trigger with only the trigger spring for resistance (no firing pin spring engaged), there's very little resistance. The trigger spring does no more than orient the trigger forward and keep it under slight pressure to maintain it's forward position. The real resistance is from the firing pin spring, but, I did try what you sent me.

I put two small washers under the trigger spring. No change that I can detect.

I loaded this gun up with live ammo and was whacking on it with a wood mallet. I pounded on it until it finally went off and shot a hole in the garage ceiling.













Ha! Got ya!

... I was going to listen to Roy, and consider what he's learned.., then I went home

Nobody got a sense a humor no mo.

I woulda used a steel sledge hammer and not a rubber mallet. And then....

I tried the Kracken black spiced Rum in Wallace Idaho.

It was better than I remember.

It is 6 more weeks b 4 I get 2 go home.

Wrong thread you old alcoholic!