GTA
PCP - HPA - C02 Gate => Crosman Discovery Forum => : melloroadman June 21, 2008, 07:51:30 AM
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I had done a 2 screw trigger mod to my Discovery and it was not what I found it to be cracked up to be. It was on the border line of unsafe as far as the sear barely contacting the hammer to archive a light trigger. I also notice that the FPS numbers were not as consistent as they were before the mod. I had heard that Crosmans A team F/T rifles had a different lower link in them . I tore my rifle down today and could clearly see that the sear had been dragging on the hammer. I removed the two screws and replaced the trigger spring with as light of one as my supply of ink pens had. Then I measured the forward hole in the trigger housing and it was a 1/4 inch father forward than the center one that the lower link was mounted in . I drilled a 1/8 hole in the lower link a 1/4 inch forward from the ordinal hole .This moved the leverage point a 1/4 further out on the lower link . I reassembled the rifle and by dry firing in the house it fills as light if not lighter than the screw mod. And there is no safety issue since the sear and hammer have full engagement just like a factor rifle . It will be Monday before I can go to the range and run new chrony numbers and get a real fill for the trigger . Here are the chrony numbers so far with CPH 10.5 Marvin
BEFORE 2 SCREW MOD. FILL 1800 - 1100
1 903
2 914
3 912
4 902
5 905
6 904
7 903
8 910
9 914
10 909
11 910
12 906
13 905
14 893
15 902
16 892
17 883
18 887
19 881
20 867
AFTER THE 2 SCREW MOD EVER THING ELSE THE SAME
1 887
2 871
3 868
4 874
5 900
6 892
7 893
8 868
9 860
10 850
11 876
12 883
13 822
14 890
15 869
16 874
17 871
18 860
19 859
20 833
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Good work Marvin! Please keep us posted. I was going to do a 2 screw mod, but I'll wait.
chris
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Chris if this does not work I am going to try one of Big Eds adjustable sears . Monday I will run the chrony numbers again and shoot some targets and that should tell me if its a workable solution . If you study the screw mod's you will see that the biggest thing it does is limit the sear engagement depth into the hammer and that is not really good. Marvin
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Marvin is the link hardened?? I have some 1/8 HSS bits and want to try that
I also have some of the older style sears that I will use
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Tom the link has about 2 thousands of a inch of hardness . Once you brake through that it is very soft. I used a dremel with a pointed metal jewelers bit to center my hole . But if you just ground or filed through the temper you could use a center punch. I used cobalt drill bits. Just make sure you center the hole good . The link is a 1/4 inch wide the hole is a 1/8 inch so that does not leave a lot of fudge room on both sides of the arm . If you want to wait tell Monday I will post the results and you will know weather its worth it or not. Marvin
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Marvin, I did the lower link mod and the two screw mod. I think you were right, I should have ditched the idea of the two screw mod. The Disco .22 for some reason is shooting all over the place now. It is shooting so bad I thought the scope was lunched out. Then I realized it is a little to Quiet,even after you get in the sweet spot !800-1600 psi.. I tested the scope on my talon just in case. It was fine. "Help" what the f*#ck did I do to this thing ? It is shooting like a Walmart Big Cat.lol Any ideas ? I will take that two screw mod out tomarrow. (Sun) The bottom one only handles trigger over travel,rght ? I don't think that one effects anything else. Does it ? And anything else you think I may have done please do tell. Thanks in advance
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John I played with the screws and had no luck . The Discovery has a different valve in it compared to other Crosmans and that is how they get a low PSI and high FPS . All I know is it reacts different to the screw mod than other Crosmans. The valve will not allow any drag on the hammer to slow it down . I believe its in the top screw and has to do with the sear engagement and release but I could be wrong. I am happy with the lower link and lighter trigger spring . I'm getting 10 shot strings in a 1 inch group at 50 yards if I do my part . I shoot 5 shots at 1800 PSI then screw the power adjuster in 1 turn and shoot the next 5 and it works for me .And the trigger is light and crisp . Marvin