New project data collection started...

[daved]

Just got a nice deal on a nearly new Gamo 890, and am planning to do a lot of work on it.  On the list is a tune (of course!), trigger work (already started), and probably a barrel chop and recrown.  I also intend to do some stock work, this one isn't bad at all, but I'd like to add some checkering to the forearm.  I may also completely strip and refinish it, the current finish is okay, but it's kind of bland, and a little slicker than I like.

I know the usual practice when getting a new Gamo is to turn the fake 2 stage trigger into a real 2 stage trigger by immediately ordering a GRT III trigger from Bob.  Been there, done that, more than once over the years, and I may end up doing it again.  But first, I want to see if I can make a good single stage trigger out of it.  That data I mentioned in the subject line was trigger pull testing, I got a Lyman trigger pull gauge awhile back and finally put it to use :-).  The 890 feels like it has a 10 lb. trigger in it, but it actually breaks pretty consistently at just under 3 lb. 6 oz.  That doesn't sound like much until you compare it to a couple of the other rifles I have on hand.  My Diana 54 with a well tuned TO-5 trigger is breaking right at 1.5 lbs. and my R9 with the Rekord trigger is breaking just under 12 OUNCES!  I love my R9 :-).

So the first order of business is trigger work.  I tore the trigger down completely last night, cleaned, polished, and lubed everything.  It feels better, but I haven't put the gauge on it yet.  It's still heavier than I want, and I think I'll have to make a couple of lighter springs to get the pull weight down.  Turns out the adjusting screw DOES do something, or it would if it was longer.  The sear engagement on this trigger is really long, with a longer adjusting screw, it should be possible to shorten up the sear engagement but still keep the trigger safe.  That MAY help lighten up the trigger, or at least make it feel lighter, but I think I'll still be making a spring or two.  Regardless, I think I can get a very nice single stage trigger out of this thing, and if it's good enough for my Remington .308, it'll be good enough for the Gamo :-).  Stay tuned, I'll be posting more later, and hopefully I'll even remember to keep my camera close by.  Later.

Dave     

[gene_sc]

Great gun to mod Dave.. Please do keep us in the loop on this project. I am sure there are many of us that will have something to learn and gain from you work.

[shadow]

Sounds interesting and I've done that with several of my Gamo's pulled the trigger housing and part's out and went through and debured and polished everything including the inside of the housing. It does make for a more consistent pull for my shooters that don't have the GRT-III in em. Ed

[daved]

Turns out a longer screw is all that's needed.  Got a longer adjustment screw, rounded and polished the the end, it's now breaking at a very consistent 17 ounces.  I was actually able to adjust it a little lighter, but it wouldn't pass the bump test, a rap on the butt with a rubber mallet set it off.  Backed the screw off a bit, and now I can beat on it with the mallet all I want and it won't go off :-).

Still have some tweaking to do.  Because I removed the trigger blade spring that gave it a fake first stage, the trigger just sort of flops around.  I need to make a washer that will fit in the blade on the pin that contacts the intermediate lever, sized to eliminate the slop.  Would have done it already, but I just thought of that :-).  I think some centering washers for the sear and intermediate lever will help eliminate some more slop, I've done that before and it made a noticeable difference.  All in all, I'm pretty happy with the results so far, and the other things I have in mind are only going to make it even better.

Did a baseline chrony today, and tore the rifle down to tune it.  I'll post tune details later, in a different post.  Later.

Dave