How I Install A Shim For A Lighter Levergun Trigger

Welcome to the Leverguns.Com Forum. This is a high-class place so act respectable. We discuss most anything here ... politely.

Moderators: Hobie, AmBraCol

Forum rules
Welcome to the Leverguns.Com General Discussions Forum. This is a high-class place so act respectable. We discuss most anything here other than politics... politely.

Please post political post in the new Politics forum.
Post Reply
Message
Author
User avatar
Shasta
Senior Levergunner
Posts: 1335
Joined: Thu Sep 06, 2007 10:50 pm
Location: Shasta County in far Northern California

How I Install A Shim For A Lighter Levergun Trigger

#1 Post by Shasta » Wed May 09, 2012 12:04 pm

In a recent thread on my .44-40 Winchester 1873 I mentioned that I had glued a shim into the hammer full cock notch to reduce the depth of the sear engagement and gain a lighter trigger pull without altering or damaging the original hammer. John in MS asked me to explain in more detail how this was done, so here is an explanation and some pictures. This procedure will work with most leverguns, in this instance the above mentioned 1873 Winchester.

First, as a disclaimer I am not a gunsmith. I am simply explaining something I did. I am NOT advocating anyone else to perform this procedure on any firearm, and if done wrong it can lead to dangerous conditions such as too light a trigger and/or accidental discharge. As they say, “Kids, don’t try this at home!”

All the new leverguns and most of the used ones I have purchased in the last couple decades suffer from excessively heavy trigger pull. My Lyman Trigger Pull Gauge measures up to twelve pounds of pull, and many new leverguns will peg the gauge without dropping the hammer. This is not especially critical for a hunting gun, but as an NRA Cowboy Lever Action Silhouette competitor, I feel that a light trigger is essential on a target gun for good scores. Personally I like a trigger in the pound-and-a-half to two and a half pound range.

Traditionally I would use my stones to remove some metal from the leading edge of the hammer’s full cock notch, thus reducing the sear engagement depth and creating a lighter trigger pull. The disadvantage is that the hammer is permanently altered, and in one instance I removed too much metal and had to purchase a new $63 hammer. I felt there had to be a better way, and concluded I could use a shim to reduce the depth of the sear engagement without damaging the hammer.

I begin by measuring the existing trigger pull. The Lyman digital gauge is a vast improvement over the RCBS spring gauge I had before. It’s easier to use and is capable of averaging multiple pull tests. I use an average of five pulls, and this particular rifle had a five pound three ounce pull, not bad but heavier than I like.

Image


I removed the hammer from the rifle and using a dial caliper measured the depth of the full cock sear notch. Experience has taught me that a depth of .020” or a bit less works well. This rifle had a notch .045” deep, so will need a .025” thick shim.

Image
Image


Since the trigger sear snaps into the hammer’s sear notch with some force, the shim should be made of steel. Rather than searching around for something that will work, I just buy a cheap set of feeler gauges. They are hard steel and have a very exact thickness. This time I am using a set purchased at a yard sale for a quarter.

Image


Here I have removed the .025” blade from the feeler gauge set and used a bench grinder to reduce its width to about a eighth of an inch. I then use a stone to smooth off any roughness left by the grinding. I have intentionally left it well oversized as it is easier to handle.

Image


Now it’s time for the adhesive. I suppose Super Glue would work, but I like JB Kwik, the fast-setting version of JB Weld epoxy. A very sparing amount is used to glue the shim piece into the hammer’s full cock notch, which has been cleaned and degreased for good adhesion. Any excess glue that squeezes out is carefully removed. The hammer is then set aside to cure.

Image


After the glue cures, the excess shim stock is neatly cut off close to the hammer using a Dremel. Final fitting is done with a stone, and then I give it a good polish, again using the Dremel.

Image

Image


A final check with the dial caliper confirmed I had .020” sear notch depth, and here you see the finished hammer ready to go back into the gun. The arrow indicates the new shim.


Image



Application of a good grease on the sear engagement and hammer pivot hole helps keep things running smoothly:

Image


One other little trick I did on this particular 1873 was install a flatwasher shim (indicated by the arrow) between the flat mainspring and the lower tang. This reduces spring pressure without modifying the spring. The spring tension screw is snugged just enough to hold it in place without adding tension to the spring.

Image


In the event I have to remove or replace the shim, it can be popped off with just a little heat and a razor knife. Then all I need to do is clean off the glue residue.

Image


After reassembly, I again check the trigger pull. Two and a half pounds. Good! :D

Image


SHASTA
California Rifle & Pistol Association LIFE Member
National Rifle Association BENEFACTOR LIFE Member


http://www.hcrpclub.org/schedule.html

avatar pic is Shasta Dam, Shasta Lake, & Mt. Shasta

User avatar
earlmck
Advanced Levergunner
Posts: 2513
Joined: Tue Nov 30, 2010 12:10 am
Location: pert-neer middle of Oregon

Re: How I Install A Shim For A Lighter Levergun Trigger

#2 Post by earlmck » Wed May 09, 2012 12:39 pm

Really great job on the write-up, Shasta. I've got a couple candidates for your technique. Thanks!
The greatest patriot...
is he who heals the most gullies.
Patrick Henry

Nath
Advanced Levergunner
Posts: 6776
Joined: Sat Sep 08, 2007 1:41 pm
Location: England

Re: How I Install A Shim For A Lighter Levergun Trigger

#3 Post by Nath » Wed May 09, 2012 12:48 pm

Interesting!

My only concern with this method is that the sears engagment is lessened!

Personally I prefer to stone the sears and maintain as much"bite" as possible. I also prefer to keep max spring loading.

I mean no dis respect to yours and others methods! A 2lb+ trigger is still a safe trigger!

Thanks.

Nath.
Psalm ch8.

Because I wish I could!

User avatar
AJMD429
Posting leader...
Posts: 22335
Joined: Sun Sep 09, 2007 10:03 am
Location: Hoosierland
Contact:

Re: How I Install A Shim For A Lighter Levergun Trigger

#4 Post by AJMD429 » Wed May 09, 2012 2:11 pm

That is a cool writeup, and done well enough even a non-mechanical person like myself can see how you did it (I might even try it myself). Is the reason you don't just file/stone the sear down, that
  • a. you'd risk messing up the angle...?
    • and/or
    b. you'd risk getting down to less-hardened metal...?
I would worry that the piece could come off and jam up the mechanism - has that ever happened to you?
Last edited by AJMD429 on Wed May 09, 2012 2:15 pm, edited 1 time in total.
Image Doctors for Sensible Gun Laws
"first do no harm" - gun control LAWS lead to far more deaths than 'easy access' ever could.


Want REAL change? . . . . . "Boortz/Nugent in 2012 . . . ! "

User avatar
olyinaz
Advanced Levergunner
Posts: 3976
Joined: Sat Nov 28, 2009 2:19 pm
Location: Tucson, AZ

Re: How I Install A Shim For A Lighter Levergun Trigger

#5 Post by olyinaz » Wed May 09, 2012 2:13 pm

Great write up! I'm interested to hear what others think of this method.

Best,
Oly
Cheers,
Oly

I hope and pray someday the world will learn
That fires we don't put out will bigger burn

Johnny Wright

User avatar
Shasta
Senior Levergunner
Posts: 1335
Joined: Thu Sep 06, 2007 10:50 pm
Location: Shasta County in far Northern California

Re: How I Install A Shim For A Lighter Levergun Trigger

#6 Post by Shasta » Wed May 09, 2012 2:32 pm

AJMD429 wrote:That is a cool writeup, and done well enough even a non-mechanical person like myself can see how you did it (I might even try it myself). Is the reason you don't just file/stone the sear down, that
  • a. you'd risk messing up the angle...?
    • and/or
    b. you'd risk getting down to less-hardened metal...?
I would worry that the piece could come off and jam up the mechanism - has that ever happened to you?

The main reason for not stoning the hammer itself is to avoid the risk of damaging an original part, plus the fact that this procedure can be reversed if necessary, which can't be done if metal has actually been removed by stoning. My incident of ruining a hammer by removing too much metal remains fresh in my mind also. :oops:

I now have three rifles with this shim treatment. My Cimarron 1873 in .32-20 has fired around 200 rounds per month for several years with no problems.

SHASTA
California Rifle & Pistol Association LIFE Member
National Rifle Association BENEFACTOR LIFE Member


http://www.hcrpclub.org/schedule.html

avatar pic is Shasta Dam, Shasta Lake, & Mt. Shasta

User avatar
Tycer
Advanced Levergunner
Posts: 6305
Joined: Sun Sep 02, 2007 10:17 am
Location: Asheville, NC

Re: How I Install A Shim For A Lighter Levergun Trigger

#7 Post by Tycer » Wed May 09, 2012 3:33 pm

I have two Win 94s done like that. Super Glue.
.
And as things fell apart, nobody paid much attention. -David Byrne
----------------------------------------------------------------
http://www.saf.org - http://www.peakprosperity.com - http://www.guntalk.com

Nath
Advanced Levergunner
Posts: 6776
Joined: Sat Sep 08, 2007 1:41 pm
Location: England

Re: How I Install A Shim For A Lighter Levergun Trigger

#8 Post by Nath » Wed May 09, 2012 3:45 pm

It don't matter what method is employed if it is good and safe, a bad stoned sear is no safer a method.

In saying that I have lost count how many I have stoned. Some of which I have gone to far but have been able to reclaim or get back. Fine slim stones I use and will sometimes finnish wrapped with 1000 wet and dry. The angle change is so minute! The hardest part is patience and many many reasemblies. The last Rem 700 took me six hours! My last 94 had a break of 1 3/4lb with full engagement and hammer spring.

IMO the advantage is the sear has full engagement and no sear chipping can take place compared to lessened engagement. Also full hammer spring weight is kept.

Sometimes a hammer can be observed moving back just a fraction before it breaks. I call this hooked sears, pump and auto shotguns sears are usually the best place to observe an exagerated instance of this. Just gentle fine stoning so this stops in most cases transforms a trigger.

But heyho thats just my way.

Nice write up and photo's Shasta :)

N.
Psalm ch8.

Because I wish I could!

John in MS
Levergunner 2.0
Posts: 428
Joined: Sun Apr 01, 2007 7:56 pm

Re: How I Install A Shim For A Lighter Levergun Trigger

#9 Post by John in MS » Wed May 09, 2012 9:23 pm

Very nice -- thanks very much for sharing!
:D

john
"Pistols do not win wars, but they save the lives of the men who do. The noble 1911 is a mechanical marvel, whose ruggedness, dependability & ferocious power have comforted four issues of GIs and which, unlike any other instrument you can name, is as much superior to its rivals today as it was in 1917."
-Col. Jeff Cooper, 1968

User avatar
Nate Kiowa Jones
Site Sponsor
Posts: 2285
Joined: Fri Sep 07, 2007 12:05 pm
Location: Lampasas, Texas
Contact:

Re: How I Install A Shim For A Lighter Levergun Trigger

#10 Post by Nate Kiowa Jones » Fri May 11, 2012 12:26 am

Your trigger hammer mod is interesting. I would not hesitate to do it on one of my personal guns for sure. But, your hammer spring mod isn't needed. The 73 has a strain screw that does exactly the same thing. This is the screw there on the bottom of the lower tang just in front of the hammer spring screw? First thing to do is back off the strain screw so that the tip is flush with the inside of the lower tang. Then lightly tighten the hammer screw then back off one 1/2 turn. Do this because the strain screw won't work if the hammer screw is tight. (notice, the hammer screw is of the counter sunk desigh so it can swivel slightly in the hole.)Now tighten the strain screw to lift the front of the hammer spring. This will give you more hammer spring. Start out with the lest amount of hammer spring then tighten the strain screw until you get consistent ignition.
This will get you the minimum hammer spring. And it's externally adjastable.
On a side note, I have never seen one come from Uberti setup where the strain screw actually works like it is suppose to.
Steve Young aka Nate Kiowa Jones Sass# 6765

Steve's Guns aka "Rossi 92 Specialists"
205 Antler lane
Lampasas, Texas 76550


http://www.stevesgunz.com

Email; steve@stevesgunz.com

Tel: 512-564-1015

Image

User avatar
Shasta
Senior Levergunner
Posts: 1335
Joined: Thu Sep 06, 2007 10:50 pm
Location: Shasta County in far Northern California

Re: How I Install A Shim For A Lighter Levergun Trigger

#11 Post by Shasta » Fri May 11, 2012 6:22 pm

NKJ-

Your explanation of the mainspring tension screw function is spot on, but what I was trying to accomplish is to REDUCE mainspring tension. On my rifle, even with the mainspring tension screw completely backed off, there was too much upward tension exerted by the mainspring on the hammer stirrup.

Since the mainspring is curved upward, raising the rear of the spring lowers the front of the spring, thus reducing some of the tension on the hammer stirrup. I first tightened the mainspring screw with the shim in place, then snugged the tension screw enough to just hold it in place. At this point, the mainspring is somewhat relieved, and the tension screw is really doing nothing at all. Granted it is better to either modify the mainspring or replace it with a weaker version, but I did not want to modify the original spring or buy a new one, and the shim trick did make a noticeable difference in spring tension.

Am I making any sense? :?

SHASTA
California Rifle & Pistol Association LIFE Member
National Rifle Association BENEFACTOR LIFE Member


http://www.hcrpclub.org/schedule.html

avatar pic is Shasta Dam, Shasta Lake, & Mt. Shasta

User avatar
Nate Kiowa Jones
Site Sponsor
Posts: 2285
Joined: Fri Sep 07, 2007 12:05 pm
Location: Lampasas, Texas
Contact:

Re: How I Install A Shim For A Lighter Levergun Trigger

#12 Post by Nate Kiowa Jones » Sat May 12, 2012 2:53 pm

Shasta wrote:NKJ-

Your explanation of the mainspring tension screw function is spot on, but what I was trying to accomplish is to REDUCE mainspring tension. On my rifle, even with the mainspring tension screw completely backed off, there was too much upward tension exerted by the mainspring on the hammer stirrup.

Since the mainspring is curved upward, raising the rear of the spring lowers the front of the spring, thus reducing some of the tension on the hammer stirrup. I first tightened the mainspring screw with the shim in place, then snugged the tension screw enough to just hold it in place. At this point, the mainspring is somewhat relieved, and the tension screw is really doing nothing at all. Granted it is better to either modify the mainspring or replace it with a weaker version, but I did not want to modify the original spring or buy a new one, and the shim trick did make a noticeable difference in spring tension.

Am I making any sense? :?

SHASTA
I understand. You could do the same thing without the shim, though. Just loosen the screw even more. The nature of the screws design will prevent it from backing out. If you don't trust it use a dab of 222 locktite (moveable) or nail polish.
Steve Young aka Nate Kiowa Jones Sass# 6765

Steve's Guns aka "Rossi 92 Specialists"
205 Antler lane
Lampasas, Texas 76550


http://www.stevesgunz.com

Email; steve@stevesgunz.com

Tel: 512-564-1015

Image

User avatar
Shasta
Senior Levergunner
Posts: 1335
Joined: Thu Sep 06, 2007 10:50 pm
Location: Shasta County in far Northern California

Re: How I Install A Shim For A Lighter Levergun Trigger

#13 Post by Shasta » Sat May 12, 2012 3:10 pm

Nate,

You got me to thinking a little harder about that mainspring shim and I finally realized that of course you are right, it is not needed. Just leaving the mainspring screw looser will allow the rear of the spring to raise just fine, and the spring should apply enough strain on the screw to keep it secure. A simple solution is the best solution, and I was complicating things for myself. Thanks for helping me to better think this through. :D

SHASTA
California Rifle & Pistol Association LIFE Member
National Rifle Association BENEFACTOR LIFE Member


http://www.hcrpclub.org/schedule.html

avatar pic is Shasta Dam, Shasta Lake, & Mt. Shasta

Post Reply

Who is online

Users browsing this forum: Bing [Bot], iceman and 10 guests