Diana 54/56 Sled Setting Tips

[Nitrocrushr]

After having spend a good bit of time with my Diana 56's, I wanted to offer up some tips regarding the sled and tension settings.  If you have already set yours up and have it shooting well, no need to make any changes.  However, if you are struggling with the fine tuning of the sled, perhaps you may find some of this helpful.

One of the key parts in getting the most out of your 54/56 is taking the time to tune both the sled lock-up tension and the stock screw torque settings together in order to optimize accuracy on target.  This takes patience, but will pay off in the end.

Each rifle will be different so I won't get into an optimum setting on either, but I will outline some things that I did.

1) Make sure that you thoroughly clean the parts within the rear slide - see below.  I use a small bore brush in order to clean any old loctite from the threads in the rear slide, as well as the adjustment screw.  You will also want to make sure that there is no dried loctite anywhere on the spring.  Depending on how this had been set-up previously, you may find that the spring is loaded up with dried loctite.  This is not a good thing as the ball bearing must be free to float against the spring along it's travel to insure smooth operation.  The spring will become very rigid if it gets loaded up with dried loctite.

2) While it is disassembled, I also dress up the spring ends to make sure there are no edges sticking out that could cause binding against the threads within the slide.  I then polish the ends up using a fine emery paper.





Note - You can see that I shortened the adjustment screw in my rear slide.  This was done to allow a greater range of sled adjustment without binding against the rear stock screw.  With the shorter screw, you can run lighter sled settings if you so desire.  In addition to this, I also shortened the rear stock screw for this same reason (See picture below).   More clearance between rear stock screw and the adjustment screw.   You can back the adjustment screw out further and not have it bind against the rear stock screw when you are torquing it up.  If your rear stock screw makes contact with the inner set screw as you are torquing things up, you lose some of the compression on the rear rubber washer, which in turn will affect accuracy on target.



3) Reassemble the rear sled, making sure that the spring and ball bearing are able to float freely within the slide.  It's ok if the spring sticks a little bit against the threads as you drop it into place, but you should be able to gently move the spring back and forth with a small allen wrench without having it get locked up within the slide.

Ball and spring in place, rails and slide reinstalled



4) Adjust sled tension to a starting point for your testing

In order to maintain a reference to where my sled is at during my testing, with the rear sled in the unlocked position as pictured below, I turn the adjustment screw in (clockwise) until it bottoms out.  I then count the turns counterclockwise until I reach the point where I want to begin testing.  For me, this is generally at minus 2 full turns from the bottomed out position.

I then begin target testing and continue until I feel that I have the optimum tension setting.  Again, I keep track of all adjustments so that I know where I finished up.  If in doubt, when you reach the optimum point for target accuracy, with the rear sled in the unlocked position, turn the adjustment screw clockwise until bottomed out and keep track of the turns, then reverse it out that same amount to return to your setting.  This setting is then documented in my notes for future reference.



5) Loctite rear sled adjustment screw.  This is a method that I have found to work exceptionally well.  With the sled set exactly where you want it, add a couple drops of loctite onto the threads directly above the adjustment screw.



6) Next, turn the adjustment screw out counterclockwise 2 full turns, and then clockwise 2 full turns again to return to your original setting.  The threads will now be coated in loctite and will set up right where you want it without the risk of getting loctite below the screw and onto the spring and ball assembly.



6) Using the corner of a paper towel, dab out all of the excess loctite from above the adjustment screw



7) Adjustment screw and threads above it are nice and clean



This method has worked for me without failure.

One other thing I would like to mention is in regards to the stock screw torque.  This is another critical setting in the tuning process, especially if you are using the factory rubber washers.  Hector Medina modifies his rifles with self leveling washers.  They work very well, and are much less sensitive to torque variation on the stock screws.  I still use the factory rubber washers, which are more sensitive to torque changes, etc.

I have run the stock screws at torque settings anywhere from 10 inch pounds, up to 25 inch pounds.  For me personally, I have found the greatest consistency and accuracy when running on the higher end of torque settings.

A couple things when torquing your stock screws

1) I have found that I get the best results when installing the stock with the rear sled in the locked position

2) Install screws loosely and with rifle resting upside down across a couple sand bags, I shake the stock around to insure that it is centered nicely onto the slides both front and rear.  This is a tip that Hector Medina gave me and I have been using it ever since.,..works great!

3) Begin to torque the stock mounting screws a little bit at a time, back and forth until each reaches the desired torque setting

Now, here is something that I recently discovered.  You may find that the sled feels like it is binding or sticking a bit when you try to run at torque settings in the 20-25 inch pound range.  While I have found that I get the best accuracy at the higher settings, you need to make sure that the sled is moving freely.  In order for this to happen, you need to make sure that the stock is level and is pulling in squarely against both slides. 

In order to fine tune how the stock sits on the slides, I made a pair of shim washers to experiment with.  I made 2 washers, one is .008" thick and the other is .010" thick.  I experimented with different combinations on the front slide, and then the rear slide.  What I found is that my sled movement is much smoother with both shims added to the rear slide - see pictures below.





With the shims in place on the rear slide (.018" total), I am able to run 20-25 inch pounds of torque while retaining a smooth movement of the sled.  This enhances the tunability of the sled lock-up tension without interference of a sluggishly moving sled.

This is another benefit to the self leveling washer that Hector uses.  As you begin to torque the stock, the washers self level and balance out the torque on each slide, thus maintaining a smooth sled action.

Another thing to look out for, is the contact between the sled reset tab (pictured below) and the inside of the cocking handle.



If the cocking handle is making contact with this metal tab, in addition to making a metal on metal clang upon closing, it also adds resistance to the sled movement.  As suggested by Roland Martens in his RWS 54 write up years back, a simple piece of rubber wedged inside of the cocking handle will quickly resolve this issue.



With the rubber in place, the metal on metal clang upon closure is gone and sled moves freely with plenty of clearance between the metal tab and cocking handle as seen below




Hopefully someone will find this information helpful.  It was a perfect rainy day to put this all into writing

Steve

[ssbn617]

Steve,
   Great write up, thanks.
Mitch

[sfcnewy]

Steve,

That was very well written and illustrated! I appreciate the time you took to make this post and your valuable time was not wasted with me...I will put your ideas/findings into my 54 this weekend.

With Regards
Ray

[BeeZee]

Thanks Steve for taking the time to write this up. It's being bookmarked as I type.

Take care, Bernie.

[thompsje]

This is amazing.  I don't even own a 54, but this makes me want to buy one just to follow this write-up.   Well done!

[Yogi]

Again, well done!

Super precise description with picture follow up.  This is what every tutorial should be.
On a different note, are you a Moly or Krytox guy?

-Yogi

[Nitrocrushr]

Again, well done!

Super precise description with picture follow up.  This is what every tutorial should be.
On a different note, are you a Moly or Krytox guy?

-Yogi

Thanks Yogi😁 On my 22mm powerplants with the dual seals I am using STP, and on my conventional tunes (and without o-rings) I use Vortek Super Moly 70+.  I’ve gotten away from Krytox.

Steve

[Nitrocrushr]

Something worth mentioning, patience is invaluable when tuning the 54/56.  Take your time and make small moves.  Avoid making multiple changes at once.  After making a change, let things settle in on target before evaluating accuracy. 

Also, make note of your settings for groups being shot.  I make notes beneath each group right on the target.  Any change made should be noted.  After you have several groups on target with various settings, it’s easy to forget the details for each group.....at least for me it is😁

One more thing...I’d recommend doing this on a calm day.  Early morning or evening are generally good in my area.  You can practice doping for the wind after you get things set up.  Trying this in breezy conditions will only hinder the results and could send you down a bad path of making needless changes.

Steve

[HectorMedina]

Great writeup, Steve!

Thanks!





HM

[Nitrocrushr]

Great writeup, Steve!

Thanks!





HM

Thanks Hector

Steve

[dtdtdtdt]

A curiosity question?

Have you ever used a trigger pull gauge or other measurement to determine how much force is required with a properly set sledge system.

[Nitrocrushr]

A curiosity question?

Have you ever used a trigger pull gauge or other measurement to determine how much force is required with a properly set sledge system.

No, I haven’t actually measured the sled resistance.  I just go by feel, manually unlocking the sled and then sliding it back and forth to determine smoothness.

Steve

[Mossonarock]

I might need to shorten my rear stock screw as you suggest. I've had it bind when trying to set the bearing screw too loose (that is, as loose as I want it to be). I might get a spare screw before I do that. I can see myself buggering it up somehow.

I didn't know about using a wee piece of rubber inside the cocking handle to eliminate binding of the handle and the cocking fin during the shooting cycle. To deal with that, I just removed the metal bracket/cocking fin and manually push the action forward into battery. Its no big deal to me; however, sometimes I do forget to do so and the recoil reminds me that I forgot.

[JohnnyPDX]

Timely post!!!

I've been wanting a quality spring piston rifle lately and started shopping this morning and ended up liking this rifle...

I'm pretty sure it's the same gun that you refer to?

http://www.straightshooters.com/rws-model-54-air-king-.22-beech-recoiless.html

[Mossonarock]

On the most part, yes the 54 and 56 are the same. The sled action makes these rifles very interesting to shoot.

[Nitrocrushr]

I might need to shorten my rear stock screw as you suggest. I've had it bind when trying to set the bearing screw too loose (that is, as loose as I want it to be). I might get a spare screw before I do that. I can see myself buggering it up somehow.

I didn't know about using a wee piece of rubber inside the cocking handle to eliminate binding of the handle and the cocking fin during the shooting cycle. To deal with that, I just removed the metal bracket/cocking fin and manually push the action forward into battery. Its no big deal to me; however, sometimes I do forget to do so and the recoil reminds me that I forgot.

I actually place one of my fingers between action and stock so that I can feel things compressing as I torque the stock screws.  I only do this out of habit now as it is no longer needed with the shortened adjustment screw and stock screw.

Regarding the action reset, I have to do the same on my short stroked 22mm rifle since the stroke bottoms out before action can be reset.  I could make some adjustments in order to get an automatic reset with the shortened stroke, but chose to leave it alone.  You get used to resetting it after awhile.

Steve

[Nitrocrushr]

Timely post!!!

I've been wanting a quality spring piston rifle lately and started shopping this morning and ended up liking this rifle...

I'm pretty sure it's the same gun that you refer to?

http://www.straightshooters.com/rws-model-54-air-king-.22-beech-recoiless.html

As Tim mentioned, the action is the same between the 54/56, so everything mentioned above would apply to either.

Steve

[JohnnyPDX]

Ok cool.

I will go take  a closer  look to understand the difference

[JohnnyPDX]

I've been looking at AOA and other places and still don't know the difference.

Found this ANIMAL and like it but of course out of stock...

Diana Model 56 Target Hunter .25
https://www.airgunsofarizona.com/spring-piston/diana-model-56-target-hunter-.25/

[Nitrocrushr]

I've been looking at AOA and other places and still don't know the difference.

Found this ANIMAL and like it but of course out of stock...

Diana Model 56 Target Hunter .25
https://www.airgunsofarizona.com/spring-piston/diana-model-56-target-hunter-.25/

The main difference is the stock.  The  54 has the sporter styled stock and comes with open sights.  The 56 has a thumbhole stock, heavy muzzle weight and a matte, parkerized-type finish.

Steve