The problem with putting a Marauder trigger in a Disco

[Sqrl Klr]

A nap hahaha! Ain't that the truth! See there you go thinking again Mike! lol

I'm not glad that I went through months of aggravation with it, especially when I had A LOT of other problems I was dealing with at the same time where I was really stressed to my limit because of it all(blowing $5k in just one month on home & car repairs, along with a medical emergency plus a family death will do that to you), but one thing out of it that I am glad about is that because of it and it being discovered then resolved by Lloyd is that this will now help other people going through the same issue where they will be spared $100's of dollars in shipping and troubleshooting plus months of aggravation trying to fix the problem.

I must also mention Norm for his help with my rifle problems too since he has also helped me a lot with it and I have a much better rifle now because of him as well. I'm privileged to know such good people who are willing to help others in their time of need.

[lloyd-ss]

Here are the pictures that I think a lot of you have been waiting for. ......."What the heck is Lloyd talking about?  Hundreds of M-rod triggers on Discos without a problem. Yes, an occasional odd duck that doesn't work exactly right of maybe even breaks, but at 99% success, what is the big deal?"

The big deal is that even though the M-Rod trigger works pretty good on a Disco, it can work a WHOLE LOT better. The pictures show why.

This first picture shows how the trigger assembly was designed to work in a Marauder rifle.
The air tube on the M-Rod is .095" thick, and about .040" of the hammer engages.
Tube wall + hammer engagement = .135"



Here is the same trigger on a Disco tube that has a .065 wall thickness. That .030 difference
in tube thickness means that the hammer is engaged for .070".  Again, tube wall + hammer engagement = .135"
BUT, That .070"  is almost TWICE AS much engagement as in the original M-rod design. Is that a big deal?  Let's see.



Here is the M-Rod hammer in an M-rod tube after it has been fully released.  The sear only had to
rotate through 3.9 degrees to release the hammer. A VERY SMALL amount of movement
to cleanly release the hammer.



OK. So here is the big deal. Because of the mechanics of the linkages, the
M-rod sear in a Disco tube has to swing through 10.7 degrees to fully release
the hammer.  That is almost 3 TIMES AS MUCH rotation to release the hammer. 
And look at that potential Jam Point where the tip of the sear hits the inside radius of the link.
I would think that if all the manufacturing tolerances built up in the wrong direction on a particular trigger,
it might cause sporadic problems.
You can see how adding a .030-.032  thick spacer between the trigger assembly
and the Disco tube would restore the mechanics of the trigger and hammer to how it was originally designed.



And one last thing.  Look at how much the sear is engaged on top of the link in this picture.
Compare it to how much it is engaged in the first and second of these 5 pictures.  Is it obvious which one is safer?
Think about how you use your gun and what you are comfortable with.
I suggest that anyone who has no more than four thumbs, remove the trigger group from their
gun, be it M-rod or Disco,  then remove the side plate from the trigger assembly, and THEN, work with the three adjustment screws and see how they affect the sear engagement and weight and feel, 1st stage, and 2nd stage.  Plus there is the 4th adjustment, the Trigger pull spring.
Follow the instructions in the owners manual.  Download it from the Crosman site if you have lost yours.
Pay attention to the slotted pivot hole in the top link, and make sure it is slid hard forward to remove the
slack from the hole.  The cocked hammer pushes that sear link forward in actual usage. 
The owners manual has two RED warnings about the trigger adjustments, and it says they must be adjusted "in harmony" with each other.  That is very, very true.  And unless you remove that side plate, I  doubt you really can tell what what your adjustments are doing.  OK, I am off the soapbox now.



I hope this has helped at least one person understand the M-rod-trigger-in-a-Disco paradox.
Lloyd-ss

[rsterne]

GREAT photos, Lloyd.... I will definitely be getting your spacers....

Bob

[Sqrl Klr]

Good pictures and info Lloyd. I said the same about the side cover on the trigger assy in another thread recently too, and that is what I did while adjusting the screws. In my case I prefer it with no 1st stage and barely any trigger travel to release the sear but I was not able to set it that way successfully without causing problems with the safety since it would not line up with it's catch pin which made the safety not work right where it would budge loose after a squeeze of the trigger then the safety would release from the catch pin and the gun would fire when I pulled the trigger again even though the safety was not moved by finger.

Plus I was having the sear catching issue as well so I had to adjust the screws where there was a lot of trigger travel to release the sear to get it firing decent, despite the sear jamming issue when cocking the gun at times. The only way of fixing those issues that I could think of was to grind the tip of the sear and bend the sear spring down but I was not about to try doing that. I would have never thought to create the spacer like you did. 

I'm wondering if the spacer will make the stock feel more loose against the tube since it only attaches to the tube by 1 screw where I can already feel the stock move slightly at times when handling the gun. I'm thinking the extra space between the two may cause the stock to knock against the tube during handling but we'll see how it goes. If so I could always place a tiny felt pad on the stock so it would not tap against the tube. I wish these stocks had 2 screws for a solid mount to the gun.

[rsterne]

The tube should sit solidly on the stock.... The trigger should move down further into the stock and if it doesn't you should find where it is hitting and grind away a bit of wood so that it can....

Bob

[MustangMike]

sign me up lloyd

[1377x]

Using the PRod trigger group on a 13XX has a different problem.... The wall thickness of the tubing is the same (0.065") but the OD is smaller and it fits deeper into the groove in the top of the trigger.... This means the sear hits the tube in front of the sear slot.... You have to either lengthen the slot or file a flat in the top of the tube for it to clear or the gun won't cock....

Bob

some 1377's dont need any modding, some do. hammer drag still seems to be an issue though
maybe it is a different problem.with my 1377 the drag mark was on top of the hammer i guess that means the p-rod sear must be psushing the hammer up some
what else can push the hammer up?

[Sqrl Klr]

Update:

I wanted to tell you that despite the shim being on my trigger assy the trigger link broke when Darrel was testing it where he had to replace it with one of his spares. He cut a small groove out of the replacement at the jam point where the sear likes to jam against it during cocking to prevent another break. He cut a groove out with the dremel just enough to prevent jams then polished it smooth with a stone. Hopefully this is a permanent fix but if not then we’ll know the trigger link will need to be replaced with one out of a sturdy metal that will not break but so far so good as it’s been cocking smooth.

[enazle]

Would you happen to have a picture of this mod?

Upon looking at the mechanics I am positive it is the super heavy hammer springs I use that is snapping the sear in my case.  Does anybody want to make me a replacement out of Steel?

[lloyd-ss]

I think I know which part you folks are having breakage problems with, but I am not 100% sure. Could you please clarify.
Per the Crosman parts diagram 
http://www.crosman.com/pdf/manuals/1763%20and%202263%20EVP%20and%20PL%20update.pdf
is it  item 6F, the sear, or item 6E, the trigger link?
I have heard of them both breaking.

The mod that Sqrl Klr is referring to involves removing some metal at the inside corner of the trigger link, where the arrow is pointing in the third picture above that says "Danger of jamming here."   That helps with the jamming, but can also weaken the trigger link, so you have to be careful.

I do not know of anyone who makes replacement parts in steel. Something like an S7 tool steel would make a good choice.

[enazle]

Mine broke at 6f. I have a friend that owns a fab shop with a water jet. He can rough one out for me out of tool steel.  It may take 3 months though.

[enazle]

UPDATE.

The shop has some scrap 1/8" 440 Stainless that was used for knife blanks that will work perfectly.  Does any one else have a need for a steel sear? 

[Sqrl Klr]

I don't have a need for one but I'd like to try one enazle.

[lloyd-ss]

UPDATE.

The shop has some scrap 1/8" 440 Stainless that was used for knife blanks that will work perfectly.  Does any one else have a need for a steel sear? 

The 440 stainless does have a nice combination of hardness and toughness and should make a very nice sear.
Lloyd