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Author Topic: Mendoza RM 377 trigger removal  (Read 148 times))

Offline Bamajoey

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Mendoza RM 377 trigger removal
« on: February 23, 2021, 10:23:10 AM »
Does anyone have a procedure for removing the trigger assembly on the Mendoza RM377. Is the spring held in by the two screws ahead of the trigger, or is the pin that holds the plastic cap on the back end what holds the spring in. Will I need to use a spring compressor to remove the trigger. Any answers to these questions will be appreciated.
Thanks, Joey
  • USA, FL, Pensacola

Offline lefteyeshot

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Re: Mendoza RM 377 trigger removal
« Reply #1 on: February 23, 2021, 11:21:32 AM »
It's been awhile, but seems you need to remove the safety levers and yes, use a spring compressor and those two screws on the bottom releases the trigger group and spring. The newer guns have two cross pins instead of screws.

The RM377 was made by Mendoza for Crosman and has a single blade trigger instead of the normal dual triggers.
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Offline lefteyeshot

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Re: Mendoza RM 377 trigger removal
« Reply #2 on: February 23, 2021, 11:37:56 AM »
Another GTA member, Avatar knows more about these Mendozas than I do.
  • Savannah, Ga.
470th, 56th, 350PC, 430
Parrus/w, Terrus/w
Dominator carbine, 155, 135
Proxima
ES92 (Spain)
BSA SS SE
Tommy
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CZ631, 634
Hammerli X2 dual cal.(Mendoza)
Mendoza RM2800 .22 brk brl repeater
RM3000 .22,RM600, TF M12
Crosman RM577, RM377
Beeman RS2.177/.22
Beeman Mach12.5
Beeman 2016W DB .177/.22
AirHawkElite wood T.H.
Blackhawk Elite bamboo T.H.
Storm in Ben.TH.stock, GRT
Storm GRT
Crosman 3100(Spain)
RWS93 (Spain)
Win.1100w,1000w,800w
2 TF99 .117/.22, TF89 .177
TF89 (chopped, shrouded Beeman .22 Brl.)
B40, B21, B26-2 MM, B20, RWS320
I.B. B3, Peak B4-2
2 QB6 .177/.22, B4-1, QB57
TS45
Fastdeer
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Offline Bamajoey

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Re: Mendoza RM 377 trigger removal
« Reply #3 on: February 23, 2021, 08:38:43 PM »
Thanks Tim for the info. Another thing I was wondering, is the pin that holds the plastic ribbed cover also holding the trigger assembly together? Maybe more folks have some answers.
  • USA, FL, Pensacola

Offline lefteyeshot

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Re: Mendoza RM 377 trigger removal
« Reply #4 on: February 24, 2021, 01:44:10 PM »
I don't remember what that pin is for. I doubt it's just for that plastic cap. Drive it out and see what happens.
  • Savannah, Ga.
470th, 56th, 350PC, 430
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CZ631, 634
Hammerli X2 dual cal.(Mendoza)
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RM3000 .22,RM600, TF M12
Crosman RM577, RM377
Beeman RS2.177/.22
Beeman Mach12.5
Beeman 2016W DB .177/.22
AirHawkElite wood T.H.
Blackhawk Elite bamboo T.H.
Storm in Ben.TH.stock, GRT
Storm GRT
Crosman 3100(Spain)
RWS93 (Spain)
Win.1100w,1000w,800w
2 TF99 .117/.22, TF89 .177
TF89 (chopped, shrouded Beeman .22 Brl.)
B40, B21, B26-2 MM, B20, RWS320
I.B. B3, Peak B4-2
2 QB6 .177/.22, B4-1, QB57
TS45
Fastdeer
Peak B3-1AK
BAM B3-1AK .22
AR2078, AR2078B 
Sheridan 2260MB
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Offline lefteyeshot

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Re: Mendoza RM 377 trigger removal
« Reply #5 on: February 24, 2021, 01:53:02 PM »
I have a dental appointment. When I get back I'll Take my 377 out of the stock. Yesterday I shot the 377 and my 577 and also my Mendoza Rm 600 and Mendoza made Tech Force M12, all .177. Today I planned to shoot my other Mendozas.

RM 2800 and 2000 break barrel repeaters Both .22
Hammerli X2 dual cal. (Mendoza RM2000 .177/.22

RM 3000 .22
  • Savannah, Ga.
470th, 56th, 350PC, 430
Parrus/w, Terrus/w
Dominator carbine, 155, 135
Proxima
ES92 (Spain)
BSA SS SE
Tommy
Norica Massimo .22, Black Eagle
CZ631, 634
Hammerli X2 dual cal.(Mendoza)
Mendoza RM2800 .22 brk brl repeater
RM3000 .22,RM600, TF M12
Crosman RM577, RM377
Beeman RS2.177/.22
Beeman Mach12.5
Beeman 2016W DB .177/.22
AirHawkElite wood T.H.
Blackhawk Elite bamboo T.H.
Storm in Ben.TH.stock, GRT
Storm GRT
Crosman 3100(Spain)
RWS93 (Spain)
Win.1100w,1000w,800w
2 TF99 .117/.22, TF89 .177
TF89 (chopped, shrouded Beeman .22 Brl.)
B40, B21, B26-2 MM, B20, RWS320
I.B. B3, Peak B4-2
2 QB6 .177/.22, B4-1, QB57
TS45
Fastdeer
Peak B3-1AK
BAM B3-1AK .22
AR2078, AR2078B 
Sheridan 2260MB
EIG 1353 co2 (Japan)
Zogunz Hawk 010 .22 (Phil.)

Offline Bamajoey

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Re: Mendoza RM 377 trigger removal
« Reply #6 on: February 24, 2021, 07:44:08 PM »
I got to thinking that the pin may hold the trigger together so I cut a 3/4 piece of 1/4 Inch dowel and drove it out with the dowel. I was just trying to reduce the 10 pound trigger to maybe 31/2- 4 pounds but I think I need to replace the spring to accomplish what Iím after. I like the Accuracy of the gun but the trigger is the pits. :(
  • USA, FL, Pensacola

Offline lefteyeshot

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Re: Mendoza RM 377 trigger removal
« Reply #7 on: February 24, 2021, 08:25:48 PM »
Took the 377 out of the stock and used a flat screw driver to lift the plastic off each end of that pin. Same thing getting it back on. That pin goes thru part of the trigger but I still think the main trigger assembly and main spring are held in by those two screws on the bottom.

When you tapped out the pin with the wood dowl did there seem to be pressure against it? Is your wooden dowl inside the receiver and not holding the trigger in?

There is a little pin with e-clips to remove the safety levers. There's not much you can do to that single blade trigger. If you had an old Mendoza parts gun you could get a dual blade trigger which is better. Can't do anything to it either but you don't need to.

The 377 ia a smaller gun but the receiver is the same diameter as the bigger guns, just shorter. If you look at the writing on the gun it might have made for Crosman.  You may already know this. Mine does as well as my RM577. also they both have blue and white spacers between the recoil pad and stock. Mendoza Mendoza's just have white. The little machine gun stamped by the writing is one Mendoza was famous for back in the day.

I shot the 377 and 577. I think the scope on the 377 is broke. Switch scopes tomorrow. The 577 was tack driving as well as the RM600 yesterday. The Mendoza made TF M12 scope might be broke also.
  • Savannah, Ga.
470th, 56th, 350PC, 430
Parrus/w, Terrus/w
Dominator carbine, 155, 135
Proxima
ES92 (Spain)
BSA SS SE
Tommy
Norica Massimo .22, Black Eagle
CZ631, 634
Hammerli X2 dual cal.(Mendoza)
Mendoza RM2800 .22 brk brl repeater
RM3000 .22,RM600, TF M12
Crosman RM577, RM377
Beeman RS2.177/.22
Beeman Mach12.5
Beeman 2016W DB .177/.22
AirHawkElite wood T.H.
Blackhawk Elite bamboo T.H.
Storm in Ben.TH.stock, GRT
Storm GRT
Crosman 3100(Spain)
RWS93 (Spain)
Win.1100w,1000w,800w
2 TF99 .117/.22, TF89 .177
TF89 (chopped, shrouded Beeman .22 Brl.)
B40, B21, B26-2 MM, B20, RWS320
I.B. B3, Peak B4-2
2 QB6 .177/.22, B4-1, QB57
TS45
Fastdeer
Peak B3-1AK
BAM B3-1AK .22
AR2078, AR2078B 
Sheridan 2260MB
EIG 1353 co2 (Japan)
Zogunz Hawk 010 .22 (Phil.)

Online Hoosier Daddy

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Re: Mendoza RM 377 trigger removal
« Reply #8 on: February 24, 2021, 09:23:57 PM »
When ever I see a 'Dozer thread I follow along.
Thanks for posting!
JimQwerty123 always said ...
"Shoot safe and have fun,"


Offline Bamajoey

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Re: Mendoza RM 377 trigger removal
« Reply #9 on: February 25, 2021, 06:42:28 AM »
Took the 377 out of the stock and used a flat screw driver to lift the plastic off each end of that pin. Same thing getting it back on. That pin goes thru part of the trigger but I still think the main trigger assembly and main spring are held in by those two screws on the bottom.

When you tapped out the pin with the wood dowl did there seem to be pressure against it? Is your wooden dowl inside the receiver and not holding the trigger in?

There is a little pin with e-clips to remove the safety levers. There's not much you can do to that single blade trigger. If you had an old Mendoza parts gun you could get a dual blade trigger which is better. Can't do anything to it either but you don't need to.

The 377 ia a smaller gun but the receiver is the same diameter as the bigger guns, just shorter. If you look at the writing on the gun it might have made for Crosman.  You may already know this. Mine does as well as my RM577. also they both have blue and white spacers between the recoil pad and stock. Mendoza Mendoza's just have white. The little machine gun stamped by the writing is one Mendoza was famous for back in the day.

I shot the 377 and 577. I think the scope on the 377 is broke. Switch scopes tomorrow. The 577 was tack driving as well as the RM600 yesterday. The Mendoza made TF M12 scope might be broke also.
I was wanting to get to the trigger to see if the spring could be replaced. The trigger group stayed in place when i had the wooden dowel in the receiver so I assume that the trigger is held in place by the two screws.
It  looks like I will just have to shoot it with a heavy trigger. :-\
  • USA, FL, Pensacola

Offline avator

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Re: Mendoza RM 377 trigger removal
« Reply #10 on: February 25, 2021, 08:00:29 AM »
Been awhile since I've been inside my twin Mendozas so I don't remember all the details.
I can tell you that there is a floating torsion spring in there. That spring determines how heavy the trigger pull is.
The spring has legs on either end that fit into 2 tiny holes.... IIRC one is in the sear and the other in the trigger blade.
I ordered lighter torsion springs from McMaster (70 ga wire, I think... it's been a few years ago).
You'll have to cut to length and bend the legs yourself. And it takes keen eyes and a steady hand to get them into place.
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