Ruger SP 101 - Change Main Spring

Ben

Moderator
Staff member
My Ruger SP 101 has always seemed to have a heavy double action and single action trigger pull.
I began reading about 2-3 weeks ago and determined that Ruger sent the revolvers from the factory with a 14 lb. main spring.

Seems that a lot of people ( like me ) wanted a lighter pull weight on their Ruger SP 101 revolvers and ordered a Wolff Spring Kit. I did the same, the kit arrived today.

The kit consist of a 9 lb. spring, a 10 lb. spring, and a 12 lb. spring.
I chose to start with the 9 lb spring. My logic is if the pistol will function 100 % and I can get the trigger pull that I want, I'll leave the 9 lb. spring in place. If I experience mis-fires, I'll install the 10 lb., if I still experience mis-fires after that, I'll have to go with the 12 lb. spring.

The main spring change out is completed now. The new 9 lb. main spring is in the revolver. I'll head to the range in a few days and see if the 9 lb. spring will offer 100 % ignition with my primers. The revolver now seems like a completely different revolver, silky smooth. The single action trigger pull is improved along with the double action pull.

Ben















This spring is under a tremendous amount of tension. If you are not very careful, parts will travel 1/2 mile when you pull the pin out of the hole . Not a bad idea at all to have your safety glasses on while doing this kind of work.



End of the strut is polished smooth and lubricated.





 
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Gary

SE Kansas
Might have to do the same procedure Ben, I love the 101 I have, it's a 357. Only thing I've "harvested" with it is a injured Coon.
 
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462

California's Central Coast Amid The Insanity
Wolff springs reside in all my handguns, and only one time did the lightest hammer spring fail the primer ignition reliability test.
 

RicinYakima

High Steppes of Eastern Washington
Following closely Ben. If it works, will you tell us what primer you used? And if it does, want to sell the 10 pounder?
 

Jeff H

NW Ohio
Single best (and one of the cheapest) upgrades that can be made on the SP101! I found the lightest spring to be just a tad "iffy" on some of my bargain European primers in Charter Arms revlovers, but Winchesters seem to fire no matter how light they are hit. In the SP101, I think the greater mass of the SP101 hammer let me get away with the lightest one in that case.

You can clean the roughness up along the length of the strut too. Those springs will bend and touch the strut and I've found the same polish you did on the knob at the top helps the DA pull a lot. If you drop that trigger group, you'll find a bunch more burrs - if you haven't already. The trigger return spring recess always has some nastiness that needs to be removed. I've left the stock trigger return spring for the sake of reliable reset and still managed a great improvement on the action just with a new hammer spring and some minor deburring.

You're probably smart enough to know this already, but it took me a while to figure it out - mark the stock spring, put it back in the package with the unused ones and stick the whole mess in the original box the gun came in. If I sell or trade a gun to someone I don't know (or sometimes know too well), I put back all the stock parts before offering it up for sale. I have a small collection of mystery springs I should have marked at some points in the past.

I want one again now. Mine was a 3" 357 with a S&W Model 60 adjustable sight fitted and the throats reamed appropriately and shot very well with cast.
 

Ben

Moderator
Staff member
I'll offer a report in a few days on the primer ignition performance of my Ruger , SP 101 with the 9 lb mainspring .

Thanks to all,

Ben
 

Brad

Administrator
Staff member
I did something similar with my GP100 many years back. I believe I went to the 10 or 12 pound spring due to a few failures to fire.
Made a huge difference in trigger pull. Even better for the trigger was firing a few K rounds in 6 months or so.
 

Intheshop

Well-Known Member
Just an observation but,has anyone ever milled a slot in that "strut" for a roller bearing?I know there was a pistol Smith years(30) ago that put one in a python action. Probably off base,nice work Ben.
 

Pistolero

Well-Known Member
Back in the middle 80s I did a trigger job on a Ruger Security Six, a lot of DNA in
common with the SP101. Took all parts out, polished the sides with oiled 600 grit Wet or
Dry on a piece of glass, just polished. Replaced main and trigger springs with a
Bullseye Spring Kit, polished the strut end and sides.
It has an outstanding trigger in both single and double action, I have gotten many
compliments over the years. I got nowhere near the sear and hammer surfaces, totally
stock, just polishing parts that rubbed on each other and new springs.

I expect that Ben will be pleased and will likely have no problems, but not sure what
weight my springs were, certainly don't remember. Whatever Bullseye was selling at
the time.

Bill
 

Intheshop

Well-Known Member
Pistolero,this is slightly on a tangent but was giving broadhead sharpening lessons to the oldest a cpl days ago......

Over the last 40+ years have accumulated just about every kind of abrasive honing/sharpening stone.From beautiful Arkansas to "real" $$$ DMT's. It pains me to say this but,those 10$ Chinese stones are probably in the upper 5% on effectiveness. These are maybe 5-8 mm thick,and then they sweep the floor in the "diamond" room and glue them on the base metal.You'll see them on ebabe....

I bought one to test on touching up carbide tooling..... and to support my addiction to sharpening stones. Turns out,they are fantastic..... oh,I still use all the "good stuff"...... my middle name is washita but,dang Chinese and their cheap diamonds,haha.
 

Pistolero

Well-Known Member
Interesting. I will have to check them out.

Ordered a set of 3 for $8.99, free shipping, in USA so quicker. Could have saved
a buck and a half shipping from China.....in 3 weeks, probably.

Bill
 
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Ben

Moderator
Staff member
UP DATE


I went to the range today with 38 Spec. ammo loaded with the following primers to shoot in my Ruger SP 101 with the Wolff 9 lb. main spring.
  1. Win. Small Pistol,
  2. CCI small pistol,
  3. Rem. Small pistol and
  4. Tula Small Pistol Mag.
My SP 101 with the 9 lb. spring fired all the primers 100% except the Tula Small Pistol Mag. ( I assume the cups may be a bit thicker and tougher for mag. pressures )
2 or 3 rounds out of 25 with the Tulas were failure to fire.

I shot them months ago ( hundreds of them ) in my Ruger SP 101 pistol with the 14 lb. factory spring with 100% ignition.

So, I came home and removed the 9 lb., Wolf Spring from my pistol and put the 10 lb. Wolf main spring in ( remember the factory main spring was a 14 pounder ) .

Back to the range soon to test this arrangement.
Will most likely ignite any of the primers I'm using right now with the 10 lb. spring.

Stay tuned......................

Ben
 
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gman

Well-Known Member
You can improve the pull a little more if you desire by changing the trigger return spring also. I've done this on just about all of my Ruger's. Both single and double action. My GP100 44 Special has a very nice single/double action trigger pull.
 

Ben

Moderator
Staff member
The spring you describe was in the " packet " that I ordered.
I've never been inside an SP 101.
Maybe it's time I change that and replace that spring also.

Ben
 

Pistolero

Well-Known Member
Trigger return is a good idea. You are always fighting it to pull the trigger, so it
directly lowers the force to move the trigger, where the mainspring is actually
indirect, only affecting how hard the sear and hammer rub.

On 1911 triggers, I never touch the mainspring, just polish hammer and sear, cut
sear back angle if needed and then adjust the three finger spring. I think you'd
like my trigger jobs on a 1911. You can ask Brad, he had a chance to shoot a
couple of my 1911s a couple weeks ago.

The three finger spring has a trigger return leg and a sear return leg. The get
adjusted separately. The third leg runs the grip safety, irrelevant to the trigger
pull quality.

Bill
 
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Ben

Moderator
Staff member
Bill,

Sounds to me like you know your stuff.
Thanks for your input.

Ben
 

Brad

Administrator
Staff member
Ben, the innerds of the GP100 family are easy to deal with. Ruger made it simple to pull the cylinder for cleaning.
I have taken mine, and the similar SRH, apart countless times.
 

Ben

Moderator
Staff member
Today, I replaced my Ruger SP 101, 357 Mag., Trigger Return Spring.
The Factory is a 12 lb. spring, My Wolff that I put in today is an 8 lb. spring.

While I was inside, Any " wear spots " got a nice mirror polish.
Everything was lubed and reassembled. The changing of my two springs, the hammer spring and the trigger return spring ( along with the polishing of parts that rub or wear against each other ) made a world of difference in how smooth my revolver functions now. My single and double action trigger pulls are both much improved.

I'm a happy camper.

Ben



 
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Pistolero

Well-Known Member
I saw my first Security Six in 1976 at a LGS in WVa. The owner (amazingly, in retrospect) let me pull
it a part to look at the insides. I was amazed at how neat and modular it was. Seems pretty much
the same basic design as the SP101. On my S6, I pulled all the parts off of the trigger guard, layed
them on a sheet of 600 grit wet or dry on a sheet of glass, with a few drops of oil and polished the
flat sides. Then wrapped 600 grit around a tongue depressor and polished the inside surfaces in the
frame pocket. Replaced the springs, polishing the strut, too. I was really amazed at the improved
trigger, both single and double.

So - I have a pretty good idea how much improvement you have, Ben. It just makes the gun a lot
more enjoyable to use, too.

Bill
 

Ben

Moderator
Staff member
Final up-date

I took the SP 101, 357 Mag. to the range this morning.
I fired Win. primers, I fired CCI primers, I fired Rem. Primers, I fired Tula Primers. I fired single action and double action.

My pistol runs very smooth now, and functions at 100%.
I'm very glad that I changed out the main spring to a 10 lb. and changed the trigger return spring to an 8 lb. spring.

Ben
 
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