LiveLife
Member
I bought my 4.5" M&P45 last month with the anticipation that I would try a trigger job myself based on M&P trigger job PDF posted on Dan Burell's website. He has disclaimers, "As a note I did not write these directions they were emailed to me anonymously, after being contacted on a forum. So we all owe him or her a big thank you!" Also, "Modifying a gun as described voids the warranty. If you shoot yourself, someone else, or anything as a result or perceived result of modifying your gun as described you are responsible." So, make these modifications at your own risk. As always, please consult a qualified gunsmith if you are not comfortable/competent to modify any part of your firearm. Be safe.
S&W website indicates M&P45 trigger pull at 7 lbs. When I compared the trigger pull to my well seasoned Glock 22 trigger, it definitely took more effort to release the striker and the trigger felt "gritty" during the trigger travel. Even with the heavier/gritty trigger pull, the front sight did not move when I dry fired the pistol.
Initial Cleaning:
After field stripping the pistol for the initial cleaning and checking the PDF, the source of "gritty" trigger travel seemed to come from some roughness noted on the trigger bar contact surface as it slid under the sear.
The barrel was measured at 0.451" at the grooves and 0.442" at the lands. My 200/230 gr lead reloads taper crimped at 0.472" dropped into the chamber freely with a "clink".
To establish baseline shot groups from the stock trigger, I did not polish any of the trigger parts. After the pistol was cleaned with Hoppes #9 and lubed with BreakFree, it was reassembled.
Range Session 1:
M&P45 barrel rifling comes coated, but not polished. At the range, I shot 200 rounds of factory FMJ (Winchester/PMC) through the barrel to "burnish" the barrel rifling (I am not sure if this is necessary anymore, but it's been my practice for years - except for Glock barrels) before shooting my reference loads (200 gr SWC and 230 gr RN Missouri Bullets with 5.0 gr of W231/HP38 - my Pro Auto Disk drops 4.9 gr).
Initial 5 yard shot groups were shooting a little to the right of POA, so the rear sight was drifted to shoot POA. 7 yard shot groups off hand averaged 1.5" and 10 yard shot groups averaged 2"-3", which is bigger than what I expected at these distances. 200 rounds of reference loads were shot.
Second Cleaning and Trigger Job Session 1:
After field stripping the pistol, barrel chamber/rifling was checked for leading. There was no sign of any leading. A few strokes with copper bore brush dipped in Hoppes #9 cleaned the barrel.
Following the PDF, I disassembled the sear housing. Since my M&P45 came with ambi-safety, it required the additional step of removing the safety (it simply slides backwards from the sear housing). =WARNING= Be careful of the small spring (1/16"x1/2") that pushes on the safety block as it popped out and I had to look for it (after 20 minutes, I found it).
Note: Since this was my "rough" run, I only did about 50% of what the PDF indicated on the filing of trigger parts. I made sure to file out the roughness on the trigger bar. I lightly filed the striker, but did not alter the firing pin block. I also did not polish my filed surfaces as I anticipate further filing/polishing after my range session.
Pistol was then cleaned, reassembled and lubed. I was very happy to feel that the gritty trigger travel was gone! Trigger pull was now smooth with more crisp striker release. However, heaviness of the trigger pull was about the same.
Range Session 2:
Since I was low on my supply of 200 gr SWC, I loaded up some 200 gr RN (IDP #4-XD) from Missouri Bullets at 1.20" OAL with 5.0 gr (4.9 gr actual) of W231/HP38.
7-10 yard shot groups off hand averaged sub 1"-1.5" and 15 yard shot groups averaged 1"-2". I then put the targets (half sheets of copy paper) at 20 yards and got 1.5"-2" average shot groups with the best 3 shot group of 1.25" pictured below.
I think this trigger job PDF certainly holds great promise as my 50% filing job surfaces are not even polished yet. I plan on doing more range tests before I file any more trigger parts as I am quite happy with the current results.
A BIG thanks to Dan Burell for sharing this information with M&P owners!
S&W website indicates M&P45 trigger pull at 7 lbs. When I compared the trigger pull to my well seasoned Glock 22 trigger, it definitely took more effort to release the striker and the trigger felt "gritty" during the trigger travel. Even with the heavier/gritty trigger pull, the front sight did not move when I dry fired the pistol.
Initial Cleaning:
After field stripping the pistol for the initial cleaning and checking the PDF, the source of "gritty" trigger travel seemed to come from some roughness noted on the trigger bar contact surface as it slid under the sear.
The barrel was measured at 0.451" at the grooves and 0.442" at the lands. My 200/230 gr lead reloads taper crimped at 0.472" dropped into the chamber freely with a "clink".
To establish baseline shot groups from the stock trigger, I did not polish any of the trigger parts. After the pistol was cleaned with Hoppes #9 and lubed with BreakFree, it was reassembled.
Range Session 1:
M&P45 barrel rifling comes coated, but not polished. At the range, I shot 200 rounds of factory FMJ (Winchester/PMC) through the barrel to "burnish" the barrel rifling (I am not sure if this is necessary anymore, but it's been my practice for years - except for Glock barrels) before shooting my reference loads (200 gr SWC and 230 gr RN Missouri Bullets with 5.0 gr of W231/HP38 - my Pro Auto Disk drops 4.9 gr).
Initial 5 yard shot groups were shooting a little to the right of POA, so the rear sight was drifted to shoot POA. 7 yard shot groups off hand averaged 1.5" and 10 yard shot groups averaged 2"-3", which is bigger than what I expected at these distances. 200 rounds of reference loads were shot.
Second Cleaning and Trigger Job Session 1:
After field stripping the pistol, barrel chamber/rifling was checked for leading. There was no sign of any leading. A few strokes with copper bore brush dipped in Hoppes #9 cleaned the barrel.
Following the PDF, I disassembled the sear housing. Since my M&P45 came with ambi-safety, it required the additional step of removing the safety (it simply slides backwards from the sear housing). =WARNING= Be careful of the small spring (1/16"x1/2") that pushes on the safety block as it popped out and I had to look for it (after 20 minutes, I found it).
Note: Since this was my "rough" run, I only did about 50% of what the PDF indicated on the filing of trigger parts. I made sure to file out the roughness on the trigger bar. I lightly filed the striker, but did not alter the firing pin block. I also did not polish my filed surfaces as I anticipate further filing/polishing after my range session.
Pistol was then cleaned, reassembled and lubed. I was very happy to feel that the gritty trigger travel was gone! Trigger pull was now smooth with more crisp striker release. However, heaviness of the trigger pull was about the same.
Range Session 2:
Since I was low on my supply of 200 gr SWC, I loaded up some 200 gr RN (IDP #4-XD) from Missouri Bullets at 1.20" OAL with 5.0 gr (4.9 gr actual) of W231/HP38.
7-10 yard shot groups off hand averaged sub 1"-1.5" and 15 yard shot groups averaged 1"-2". I then put the targets (half sheets of copy paper) at 20 yards and got 1.5"-2" average shot groups with the best 3 shot group of 1.25" pictured below.
I think this trigger job PDF certainly holds great promise as my 50% filing job surfaces are not even polished yet. I plan on doing more range tests before I file any more trigger parts as I am quite happy with the current results.
A BIG thanks to Dan Burell for sharing this information with M&P owners!
Last edited: