Archer Super Sear

[quickster47 †]

I installed the Super Sear in my 2240 yesterday. It did make a very discernible difference in the trigger feel. It actually has two stages now, makes it a lot more predictable when it will fire. It does have a heavy (but short) trigger pull on the second stage with a stock Crosman spring. The spring I had shortened to reduce the pull of the horrible original trigger feel did not have enough pressure to hold the super sear in position (it rides under the sear pin instead of having a hole in it) without the gun being cocked.  I do plan on getting 1701P trigger frame group for my 2400kt, so when I do, I will update with differences I feel between the two guns.

Most all of us here will definitely be interested in reading your results/opinion of the mods you have done and how it has helped your shooting.

Carl

[JMJinNC]

The spring I had shortened to reduce the pull of the horrible original trigger feel did not have enough pressure to hold the super sear in position (it rides under the sear pin instead of having a hole in it) without the gun being cocked.

I installed Dave's Supersear in my 1377 carbine and ran into this issue - the sear slid backwards with the hammer and would not engage it. The sear spring I had installed was trimmed a bit, so the force required to retain the sear in position was too low. Not sure I want an OEM spring in there though.

So, I reinstalled my OEM sear and started pondering. I may try modifying the sear to retain it front-to-back but still allow the up-down translation which produces the leverage change/2-stage feel. A vertical groove for the pivot pin is what is called for - not sure why the design has an open face that allows the sear to move backwards (unless I'm missing something).

Also, there's an unused pivot-pin hole just aft of the sear in the grip frame. I might try installing a Delrin block there to prevent rearward movement of the sear. Another option is a leaf spring to hold the sear forward.

Or just go back to a full-strength OEM sear spring... hmmm.

http://3.bp.blogspot.com/-_mf2jhRRHjk/UQEf1XRuohI/AAAAAAAABYo/bOlPH39GZRM/s1600/SuperSear-High-web.jpg

JMJ

[DaveB50]

That's what I was saying about the super sear Jim, it needs a certain amount of tension to hold it in place. As I had the 1701P grip frame assy. ordered, to compare with it, I didn't try anything else with the super sear. I was surprised that you could not use lighter or modified springs with it. The instructions that come with it tell you not to use anything but the stock spring, they should put that in their ad. The 1701P grip frame assy. made a lot of difference in the trigger pull, it has a drop sear design that lets you adjust the two stages separately. The super sear, IMHO, was better than the stock set up, as you knew when it was going to fire, but I could not change the second stage pull pressure, which I thought was too high. Jim, let us know how your mods work out. If it doesn't, at least you didn't have to pay full price for it.
Dave

[BDS]

Dave and JM:  Longer spring with much thinner coil wire!    A concentric coil spring has two modes of work; 1) un-compressed length or passive tension.. and 2) compressed length or reactive tension

The trick is to find the thinnest wire coil that acts as a"spacer" in the passive or uncoiled condition to keep the sear in place and also to cause a good lock-up when cocking the gun. The amount of sear polishing and trigger polishing and lube also affects the spring choice. It's a bit of trial and error but... I've gone to using very thin 10-32 flat washers to make up for spring length on the lower spring mount (the lil nub in the frame that holds the spring). That way, I can fine tune the tension without messing with dozens of springs 

PS I've also found that the Crosman (brass) spring adjuster occupies too much length to be effective and... they also seem to lossen too easily over time (locknut loosens) so that's how the thin washer idea came to be..

[JMJinNC]

Switching to a lower K-value spring with a much higher preload will result in the same force on the sear prior to moving the trigger, but a much lower increase in trigger force as the spring is compressed further. The problem is that the spring is much more prone to buckling, so an internal (or external) guide is required.

Example:
Spring 1 - free length is 1.5", k = 20 oz/in, compress to 1" height (.5"x 20 = 10 oz force). Further compression of .100" results in 12 oz force at end of trigger pull, 20% increase

Spring 2 - free length is 3", k = 5 oz/in, compress to 1" height (2" x 5 = 10 oz force). Further compression of .100" results in 10.5 oz force at end of trigger pull, 5% increase

Note: k=spring constant or force/unit length

My issue is trigger force. Using the "high force" OEM spring to retain the sear in position is inefficient. A mechanical stop is all that was required.

When I got the sear, I did a thorough polish on all contact surfaces. Unfortunately, the design actually relies on friction to prevent fore-aft motion. Okay - my bad.

I might also drill & press in a small dowel pin forward of the pivot pin interface to effectively form a groove for the pivot pin to slide in.

JMJ

[BDS]

Yay... another spring guy on here, I tried to stay away from the "techie" values, k factors etc, but you are on it like a shark JMJ! 

[JMJinNC]

Heh heh... it's my job!

Crazy idea below.

JMJ

[BDS]

Cool... We use Lee Spring and Century Spring for many of our assembly jobs, both cos. have helped me become an "armchair-expert" over the years. Do you recognize those guys JM?

[JMJinNC]

Lee and Century - great to work with.

We buy a lot from McMaster Carr, but when you need precision or custom, Century is the bomb.

I've designed a few springs in my time, including a cantilever/pivoting design with a flat spring rate through the majority of it's range of motion (same force over 40° arc, preload to final). Shoulda patented that one, shucks!

JMJ

[BDS]

Heh heh... it's my job!

Crazy idea below.

JMJ

Maybe not so crazy!? Using the "hollow" of the spring ID almost like a detent right? Just enough to keep the sear from flopping down. Now, how to keep the spring in place without exerting too much force on the sear ...hmmm 

[JMJinNC]

I think I can file 2 notches on the rearward face of the sear. This will locate one end of the spring. The other end will just rest against the rear wall of the grip frame.

Since this spring will be acting 90° to the trigger spring, it will not contribute towards trigger effort. It will just keep the sear from moving due to cocking the hammer.

Should be easy enough to try out without modifying anything.

JMJ

[chongman]

Fantastic thinking JMJ, I have a sear inbound right now and will keep a watch on the doings 

[DaveB50]

Jim, that spring just might do the trick, another idea would be to attach the inner and outer washers to the sear,  maybe try it out with some double sided tape, if it works, you could solder them on.
Dave

[JMJinNC]

Can't attach the washers to the sear - the sear is supposed to slide with respect to the pivot pin.

1st stage pivot is the bump on the top of the sear, and the sear is actually sliding a bit on the pivot pin. Once the sear bottoms on the pivot pin, pivot location switches to that location (2nd stage), trigger "weight" increases due to reduced mechanical advantage and sear release of the hammer is rapid.

The trigger weight at 2nd stage should be the same as the OEM sear, since the leverage is the same (using same pivot location).

JMJ

[Brent]

Lots to learn... and good info here. Subscribed