gth813x

can someone please explain to me what is necessary to decrease trigger weight by changing the sear on my sp101, i have a 3" sp101 that is DAO (not a bob job).

if you have pictures or something that would be helpful as well.

if you're just going to say don't do it just switch a spring please don't post anything. i'm not dumb and want to see what would be necessary and decide if i want to do it myself or not.

ironhat

You would be surprised what a little polishing with a Dremel, a buffing head and some red rubbing compound will do. You should not try to get the milling marks off or you will likely go through the hardened surface. If it doesn't feel like you have shaved some weight from the pull, and that's not what you're after here, it does wonders for the feel of the trigger. My Ruger SS went from a trigger that was fairly stiff and gritty to one that my grandkids can enjoy using. Whatever you do, don't remove too much material. If the trigger feels less gritty but still a bit so, just repeat the process judiciously. You can always remove a little more but you can't put material back on.

Xringshooter

The trigger weight will not change by doing anything to the sear. That can only be done by changing springs. However, the polishing of the mating surfaces of the hammer and the trigger will make the trigger smoother which will make it seem to be lighter. When you work on a competition gun, you polish the surfaces, change springs and polish other parts like the pivot point of the main spring strut (the top rounded part) and the recess where the strut mates with the hammer.

tglazie

Deburring/sanding the entire length of the strut is helpful. I am a big proponent of reducing drag in all areas of the action. A good deburr/sanding of the side surfaces/edges of the various moving parts, as well as the areas of the frame that they contact, can do wonders for an action. You can make a trigger feel a good bit lighter just by performing a good action job that is light on the mating surface polishing and more focused on the cleaning the rough edges/surfaces. Likewise, installing good shims (like those from triggershims.com) is a great way to ensure that your action is free of drag. When you shim- dont forget the hammerdog shims. Everyone does the trigger and hammer- why not the hammerdog too?

Mr Sasquatch

Before you touch that sear read this:

SP101 Sear Improvements

Patricularly Iowegan's two posts.

pell

Yes and no.
- The strut is box shaped and the spring cylindrical. The spring contact with the strut (when it occurs) is on the strut "corner" edges. Dressing up the corners edges is helpful.
- The spring compresses from the bottom up, not uniformly over it's length. Dressing up the corner edges @ the bottom 1/3 of the strut is more helpful that @ the top 2/3.

You will suffer no defect from polishing the whole of the strut, but you will be exposing a lot of fresh surface to corrosion.

ironhat

Nice comment deburring any contact-riding surfaces but, would you like amplify about the shims? Are there already shims in the gun or is that something done to take up slack only in a worn action or both? I assume that any good gunsmithing supplier has shim stock but what thickness do suggest having on hand?

Thanks again,
Chiz

tglazie

Interesting point, and certainly something I will consider when it comes to when I should tear down the gun for a good cleaning/conditioning. I do take for granted the stainless steel aspect of the SP101 (and all my SS guns) at times. I agree that the various components in the gun each corrode at their own rates and that should be accounted for when you disrupt their surface condition.

tglazie

There are no shims in a Ruger SP101 from the factory. In general, the guns that Ruger makes tend to be heavy on strength and durability and light on polish/feel (especially when it comes to triggers, certain models not withstanding). It takes time and effort to go through the process of measuring the excess space in each and every action at the factory and then adding shims. This is not something that is possible with a ruger-priced firearm (or any non-custom job, really). There is certainly no reason that we cant take the time and effort to optimize though. After all, we get to live with the gun forever

Usually folks who shim make their own shims from feeler gauges. You use the gauges to measure the shim thickness you need (add up the total gap for both sides, subtract .002" and divide by 2 then cut the shim you want and drill a hole in it. You can also go another route which is buying shim kits (an assortment of various thickness shims) from triggershims.com and get stainless shims that are perfectly round. I much prefer this to hacking off a piece of stock. I just got various sizes of trigger, hammer, and hammer dog shims and used the ones I needed. The other will go in the toolbox for another pistol or gun. I have already used 2 of the spares for an old 101.13 JC Higgins .22 trigger. Extra gun parts always find a home

Iowegan

tglazie, Good posts and right on target! I thought I would elaborate a little on shims and what they do. First, take a look at the sides of your hammer. Chances are there are arc shaped scratches on one side and maybe both. This means the hammer is allowed to wander back and forth on the hammer pivot pin and drag on the frame ... not enough drag to cause misfires but you will get a raspy feel in the trigger. Next, look at your trigger pivot. Chances are it has way too much side play. When a right handed person pulls the trigger, it will wander to the left on the trigger pivot pin and rub on the pivot pin frame. Opposite for left handers. When either side of the trigger rubs on the pivot pin frame, you will also get a raspy feel. Last is the hammer dog, which is mounted in a slot at the base of the hammer. Again, there is always some side play that allows the hammer dog to wander on the trigger cam.

When shims are installed, it keeps the hammer centered so it doesn't drag on the frame. Trigger shims keep the trigger centered and also prevents the trigger from rubbing on the pivot pin frame. Hammer dog shims keep the hammer dog centered so it doesn't drag on the slot in the hammer.

Here's what happens when you pull the trigger in the DA mode (factory gun) .... The trigger cam will pick up the hammer dog and start moving the hammer back. Meantime, the side play in the trigger allows the hammer dog to slip sideways, which is compounded by the hammer's side play and the hammer dog's side play on their respective pivot pins. Typical hammers have at least .010 side play and about the same for triggers and hammer dogs. So in total, the three parts can accumulate .030" or more side drift. When mating surfaces on parts are moved slightly sideways instead of straight, it creates friction and makes the trigger feel gritty. I like to see equal thickness shims on both sides of these three parts with about .002" of side play in all three. This will reduce the gritty feel considerably. When the SA sear it set (hammer cocked), having the trigger and hammer aligned straight also reduces SA trigger pull creep and makes the sear much crisper, although not much (if any) lighter. If you compare one gun with shims to another without shims, you will certainly feel the difference, favoring the shimmed gun in both SA and DA modes.

tglazie

Thanks for the kudos Iowegan. It was your ruger knowledge and instruction that brought me to this site originally, specifically so that I could learn as much as possible about my (wife's) SP101. It is certainly a nice piece of engineering that with the right knowledge, and some patience, can be made into a jewel of a shooter.

I have learned more about gunsmithing from reading your posts and the posts of other knowledgeable smiths on this site than I have any other source.