Wee Hooker
Member
I started the install of a Apex Duty Cary Kit in my MA compliant 9C yesterday and figured I'd share some interesting results with the board. This particular gun has seen maybe 700 rounds total to date. I'm installing the kit in phases so I could monitor the effect of each change. ( Yea, it's the engineer in me !) Here you go.
Start: MA compliant M&P w factory sear, trigger return and sear springs.
Results: Some minor grittiness in take-up but it was masked by the firmness of the pull. Trigger broke at a consistent 10#, 4 oz trigger with some creep. Near impossible to hold the gun still at break due to the trigger mashing into the trigger stop.
Step 1: Replace factory trigger return spring with "48 state" factory spring.( Brownells part # 940-000-695).
Results: Grittiness seems exadurated by lighter pull. ( Not worse, just more noticeable) Trigger breaks at 7# 2 oz with some creep JUST prior to break. Less movement at break if your really concentrated and slowed the pull down. Significant improvement in "shootability".
Step 2: Installed Apex sear only ( Sear spring remained unchanged on the advice of Apex. Apex sear spring is lighter than MA sear spring.).
Results: Significantly smoother pull with any remaining grittiness isolated to the slide. Trigger breaks cleaner and consistently at 5# 4 oz. No movement of muzzle at break. NICE trigger and not to light for intended CCW use.
General note: I'm not sure why Apex advertizes and advises against replacing the sear spring on MA compliant M&P's as part of this upgrade. ( I'm thinking legal vs tecnical reasons .) Seems to me, that once the trigger return spring is replaced from the 10# unit , their lighter sear spring should match fine with the rest of their matched components. I was tempted to test this but seem no reason to tear the sear out again as I've got it pretty much where I want it with just the Apex hard sear and 48 state spring. Safe yet shootable.
Step 3: Swapped the APEX Duty kit trigger return spring (which is reportedly stronger than the 48 state factory spring but lighter than the MA spring.) with the 48 state factory spring.
Results: Significantly heavier trigger pull with a consistent break at 6# 11 oz. Some movement of gun at trigger break. Nothing else seems to have changed. Not all that much improved over the step 1 really. Interesting to note here is that Apex predicts 5# to 5# 8 oz with fully installed kit with no reference to M&P variant. I have not yet changed the MA sear spring or striker block plunger assembly. It appears the 1.5# delta be due solely to the heavier MA sear spring.
Step 4: Brought the gun back to Step 2 configuration buy swapping the factory 48 state spring back in. This seems to give me the best combination of a safe but shootable gun so far.
Actually toyed with the idea of trying the MA 10# spring and the Apex sear just to get the data point but didn't bother since I'm not going there anyway.
I'll get around to changing out the striker block plunger with the apex unit latter this week ( Waiting for my sight pusher tool to come in.) I'll update then.
Hope you found the info useful or at least interesting.
(p.s. Forgive the spelling errors. That's the engineer in me too!)
Dave
Start: MA compliant M&P w factory sear, trigger return and sear springs.
Results: Some minor grittiness in take-up but it was masked by the firmness of the pull. Trigger broke at a consistent 10#, 4 oz trigger with some creep. Near impossible to hold the gun still at break due to the trigger mashing into the trigger stop.
Step 1: Replace factory trigger return spring with "48 state" factory spring.( Brownells part # 940-000-695).
Results: Grittiness seems exadurated by lighter pull. ( Not worse, just more noticeable) Trigger breaks at 7# 2 oz with some creep JUST prior to break. Less movement at break if your really concentrated and slowed the pull down. Significant improvement in "shootability".
Step 2: Installed Apex sear only ( Sear spring remained unchanged on the advice of Apex. Apex sear spring is lighter than MA sear spring.).
Results: Significantly smoother pull with any remaining grittiness isolated to the slide. Trigger breaks cleaner and consistently at 5# 4 oz. No movement of muzzle at break. NICE trigger and not to light for intended CCW use.
General note: I'm not sure why Apex advertizes and advises against replacing the sear spring on MA compliant M&P's as part of this upgrade. ( I'm thinking legal vs tecnical reasons .) Seems to me, that once the trigger return spring is replaced from the 10# unit , their lighter sear spring should match fine with the rest of their matched components. I was tempted to test this but seem no reason to tear the sear out again as I've got it pretty much where I want it with just the Apex hard sear and 48 state spring. Safe yet shootable.
Step 3: Swapped the APEX Duty kit trigger return spring (which is reportedly stronger than the 48 state factory spring but lighter than the MA spring.) with the 48 state factory spring.
Results: Significantly heavier trigger pull with a consistent break at 6# 11 oz. Some movement of gun at trigger break. Nothing else seems to have changed. Not all that much improved over the step 1 really. Interesting to note here is that Apex predicts 5# to 5# 8 oz with fully installed kit with no reference to M&P variant. I have not yet changed the MA sear spring or striker block plunger assembly. It appears the 1.5# delta be due solely to the heavier MA sear spring.
Step 4: Brought the gun back to Step 2 configuration buy swapping the factory 48 state spring back in. This seems to give me the best combination of a safe but shootable gun so far.
Actually toyed with the idea of trying the MA 10# spring and the Apex sear just to get the data point but didn't bother since I'm not going there anyway.
I'll get around to changing out the striker block plunger with the apex unit latter this week ( Waiting for my sight pusher tool to come in.) I'll update then.
Hope you found the info useful or at least interesting.
(p.s. Forgive the spelling errors. That's the engineer in me too!)
Dave
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