Re: cva optima rifle trigger assembly
Here are a few more notes.
DISCLAIMER: Remember, I'm not a gunsmith and I don't play one on TV. You can hurt yourself and others if you actually attempt to fire your CVA rifle with live ammo after doing the things I describe here, and that's your problem and not mine. For the record, I fear that I've not only voided my CVA warranty but also made my rifle unsafe for live fire. Hence, I will never shoot my modified rifle. I performed these modifications only as an educational exercise.
You don't have to remove the top pin that holds the break action latch in place. Just remove the hammer cocking assist nub (left-hand thread) and drop the hammer out the bottom. It's optional to remove the plastic end on the break action latch lever--it would be easier if it's not in the way, but I just left mine in place.
When you punch out the bottom pin, the trigger guard, trigger, trigger return spring, and action latch coil spring come out the bottom. Try to push forward on the trigger guard to keep it hooked in place as you tip the back of the trigger guard down and out. Hopefully, you'll be able to see how everything is situated before everything pops out!
The hammer and hammer spring come out the bottom after punching the hammer pin out. Again, just leave the top action latch pin in place.
You can actually re-assemble the trigger and hammer mechanism on the outside of the frame to see how it works. I recommend using slightly undersized pins from Ace Hardware. (You might have to turn them down a touch--perhaps just with emery cloth in a drill, depending on what sizes you find.) You can optionally install the hammer spring and trigger return spring when doing your investigation on the outside of the frame too. If you leave them out, just use your fingers to apply pressure and manipulate the parts instead of using the springs.
You'll see a 90 degree sear notch on the hammer and the associated sear "tab" on the trigger that engages into the sear notch. On my trigger, the sear only contacted the hammer sear notch surface at the very tip of the trigger's sear "tab." The hammer sear notch is about .020" deep. ideally, you want the sear surface on the hammer contacting along most or all of the .020" deep surface of the hammer sear notch. I think it's best to adjust the surface on the trigger to match the surface of the hammer sear notch. I did much more than that and wish that I'd just done what I'm recommending here. I changed the angles of both surfaces to make the hammer "squirt" more easily off the trigger sear surface. I probably angled both surfaces at something like 20 to 25 degrees away from the standard square orientation, and I used a milling machine to do it accurately. The change in geometry makes the trigger very, very light, and it would likely require a custom transfer bar actuator like I had to fabricate. My trigger geometry still doesn't exhibit negative sear engagement but it is very close to neutral, like the original geometry. It functions perfectly after releasing the trigger from an aborted pull and it is very crisp, like the original, but would be very light for a hunting trigger. Finally, it required a lot of extra work to make and custom fit a new transfer bar actuator. BTW, don't remove the transfer bar actuator from the trigger unless you decide to replace it with a new custom one--it's peened in place on the trigger.
Simple stone work and maybe a file with a "safe" edge should be enough to rework the hammer sear surface parallel to the hammer sear notch surface. After it looks good under a magnifying glass in a test assembly on the outside of the frame, polish the surfaces using a Dremel tool and metal polish, or other method. I also recommend polishing the tip of the trigger return spring that contacts the trigger and the area of the trigger where the spring makes contact. Clean and lube the surfaces. I use a high moly content grease--like moly brake grease with even more moly assembly lube (nearly 100% molybdenum disulfide) mixed-in.. The spring does move a bit on its trigger surface and that causes a bit of friction so dab it with lube too.
If the trigger is still too heavy, it's probably possible to reduce the spring constant with a new and lighter trigger return spring, but it doesn't contribute much to the total pull. I left mine alone, because I surely don't need a lighter pull!
Install the hammer, hammer spring and hammer pin. It's pretty easy to re-assemble everything, if you have a very short trigger pin to hold everthing in the trigger guard while it's being inserted into the frame. First start the original trigger guard pin into the frame just enough to hook the hammer spring arm onto it. Then insert the trigger guard and parts held in place with the short and undersized Ace Hardware pin. Put the action latch coil spring in place and push the trigger guard forward and into the frame to put pressure on the action latch coil spring against the action latch. If you hook the front end of trigger guard into the frame just right, the back of the trigger guard can be levered up and into position. Then drive the permanent pin through to displace the undersized and short "dummy" pin out the other side. it takes some practice.
Last edited by calinb; 10-12-2011 at 07:02 PM.