Crosmods sear and sear spring concerns

[airriflenut]

I was wondering if any of you guys that have the Crosmods trigger assembly have had any issues come up with premature firing?  I've noticed lately that my 1377 with this trigger assembly is firing if the gun is slightly bumped or jarred!!  Not a good thing, especially since these units have no safety but I don't think a safety would remedy the issue at hand.

When I got this trigger assembly a few months ago I fell in love with the light trigger, as I examined it closely it dawned on me that the trigger pull was so light due to a VERY light sear spring.  By light spring I mean very small diameter (I haven't put my digital calipers on it yet but I soon will) wire and very few coils per inch.  It is topped off with a red plastic cap for the sear contact point.  At this point no more thought was given to any of these things because I wanted to get my Scorpion done.

First issue to come up: shortly after the build it got to the point it would not stay cocked.  When i examined the unit I noticed that the sear spring had actually "jumped" over the retaining lip of that red plastic cap (it has a VERY thin lip) and that was binding it up causing it not to cock.  That was easily fixed by turning another cap out of Delrin...this issue resolved.

Newest issue:  I have been puzzled by the premature firing so with an empty barrel and no pumps I cocked the sear and LIGHLTLY bumped the gun with my hand..."slap", the sear slipped and the hammer struck with full force.  I repeated this about a dozen more times, some with it pumped but unloaded and the same thing EVERY time!!  I thought I had moved the adjustment screw on the trigger out too far so I moved it in more (NOTE: these trigger units also have a small sear engagement screw above the larger adjustment screw, I have this smaller engagement screw completely backed out) and the sear still slips.

I took the unit off the gun and removed the sear and did NOT like what I saw.  The sear is showing wear on the top and a small burr has formed opposite the engagement point...the sear is NOT HARDENED!!!  Since I don't have a stiffer spring to replace the very weak one I did what any Redneck Polock would do...I stretched it out a little.  After putting it all back together I did the "bump test" again, the sear is still slipping out of engagement but it takes a slightly harder bump to do it. 

In my honest opinion the sear spring should be of slightly heavier gauge wire and the sear should have been hardened to reduce/eliminate this premature wear of the engagement point.  I can fix the spring issue with another spring.  I don't know what type of steel was used for the sear so I am not sure of its hardening requirements, I have some woodturning cutters I made from HSS that I need to oil-quench harden, I may go ahead and see if the sear will harden this was as well...a quick file test afterwards will tell if it hardened or not.

Anyway, just wanted to pass along my findings in case any other Crosmods trigger owners are having similar issues.

[breakfastchef]

I believe you are on the right track. When the sear spring is weak, you certainly may get an unsafe gun. Also, the sear burr is a bit unnerving. Perhaps you are experiencing some sear drag on the hammer, too.

[airriflenut]

There could be some sear drag on the hammer but I have had many years experience shooting pistols and I have a good follow-thru with the trigger, this should keep the sear down long enough for the firing cycle.  The burr could be a result of the trigger screw out to far (contacting the sear more forward for lighter/better "feel") but if the sear had been hardened the burr never should have formed.

I am going to take some stones to it to remove the burr and re-polish the engagement surface before I try to harden it.  I'll post how that turns out.

[1377x]

do you think the sear still has enough engagemeen contact points?
if you know how to harden steel and the sear is still safe to use,it wouldnt be a bad idea to harden it
if you can a piece of stainless steel to make another sear out of it could be done with hand tools like a dremel and some files
i had a firearm called intratec tec 22 this gun eats firing pins like a chubby kid at a candy store eats candy.
i got sick of the firing pin breaking and made one out of a stainless steel butter knife.that firing pin lasted many more rounds than a cold rolled tool steel hardened firing pin
one i got past double the shots it normally would break in i sold it.the butter knife firing pin never mushroomed didnt cut into the casing to deep.it was good as gold.
you might try to solder,jbweld, tac weld two stainless steel butter knives together and make a new sear unless you can get a piece of it

[airriflenut]

It looks like there is still enough sear protrusion to work since I caught the problem early, I'll have to take some measurements to be sure.

If I have to I can always add some SS flat bar to my order to Online Metals next week since I will be ordering more 1018 cold rolled rod, 6061 aluminum round and square bar for some woodturning tools I am making.

[1377x]

It looks like there is still enough sear protrusion to work since I caught the problem early, I'll have to take some measurements to be sure.

If I have to I can always add some SS flat bar to my order to Online Metals next week since I will be ordering more 1018 cold rolled rod, 6061 aluminum round and square bar for some woodturning tools I am making.

flat bar thats what i was looking for and just couldnt think.i have a cool hardware store that will sell you any qaunity of round,flat,hex bar stock they have
i saw some nice 3/4 hex brass bar stock that would make a nice breech

[airriflenut]

I've never had the pleasure of seeing one of the hex breeches in person, brass or otherwise.  I bet they they are very nice.

[1377x]

airgunsmith used to have a hex brass breeches he said he was going to sell them and then never put them up for sale.just a couple of his personal breeches made it to the market.i offered to pay him up front for a brass breech he didnt want the money.
im so happy with my Anthony R aluminum breech as long as they are available i wont get any other kind from now on

[airriflenut]

Do you have any more info in that Anthony R breech you mentioned?

[1377x]

they come in either left or right hand bolt everything you need to mount them and an end cap comes with it meaning 2 grub screws for the barrel yes it has 2 set screws not 1 like the steel breech philips head breech screw stainless shortened rear breech screw bolt handle of your choice 8 to choose from
contact pm fivestar45 here on the forum they are his breeches he has more stuff too safeties barrel bands pro top he can tell you more

[crossliner]

they come in either left or right hand bolt everything you need to mount them and an end cap comes with it meaning 2 grub screws for the barrel yes it has 2 set screws not 1 like the steel breech philips head breech screw stainless shortened rear breech screw bolt handle of your choice 8 to choose from
contact pm fivestar45 here on the forum they are his breeches he has more stuff too safeties barrel bands pro top he can tell you more

How about some eye candy from his site or does he have one Mr. 13?

[1377x]

he doesnt have a sight i posted a pic of the breech i got in the custom 2300 thread and the fed ex thread he also has an ad on the yellow search by date aluminum breech,