M&P 9 fullsize getting light strikes 80% no joke

[datsthat]

PLEASE help with any ideas. If I can't figure this out (without you guys help), then its off to Apex or gunsmith (any suggestions in or near WA State)

Started out with a brand new stripped slide (purchased off somebody on different forum) that had been Ionbonded. Got machine work done to remove weight & mill for MRDS (weight of slide w/ MRDS (no barrel or guide rod) = 10.5oz).

Installed FSS Kit, FRE, KKM 5" barrel, Catalyst Extended Mag Release and the rest of parts from SSS. 1 out of roughly 51rds, slide wouldn't return completely to battery after firing a shot. Stops roughly 1/4" away from complete battery. Cut couple coils off extractor spring and problem solved (for now).

Now the pain........light strikes (10-13 out of 17). Doesn't mater which ammo I use (S&B, Rem UMC, Blazer, Magtech. only reloads are Washougal River 115gr). Round usually would fire if I reuse but it may take up to 5 tries. The dents are somewhat centered. With the rounds that took muiltple attempts has dents that are VERY close to each other, but you can still tell that its slightly off from one another.

Swapped with a different stiker assymbly that worked perfectly on a different gun, but still have light strikes..didn't leave it in long enough to determine if it reduced the light strikes. I removed the striker liner and cleaned the channel...barely dirty with no lube.

I tried any of the following combination of 11# & 13# ISMI spring w/ SSS uncaptured rod or factory captuted rod & spring or DPM Recoil Guide Rod with Competition striker spring or Extra power striker spring or Factory Striker Spring. Factory rod & springs w/ extra power striker spring yeild best results, which is 8 out of 17.

Is there a chance KKM chamber is too long which limits the stiker reach? I will swap barrels next chance I get.

I wonder if this is related to slide not returning to complete battery issue?

Edit: Thank you for the responses so far. below are some answers to your questions

• I have tried factory guide rod & factory spring, but still get light strikes. I didn't keep it in long enough to tell if it reduces any light strikes
• Tried removing the firing pin block aka striker block plunger to see if the stiker leg was hitting it, but still got light strikes
• I have 15 & 17# ISMI springs coming...sounds like I may need to get 20, 22 or 24#. I thought one of the reasons one would lighten a slide is to use lighter recoil springs? Maybe I went too light which caused an inverse effect?
• I'll get some pics up after I go to range next

Edited December 11, 2013 by datsthat

[CPW1265]

i have a 9L and the Apex Competition AEK kit and aluminum AEK trigger and swap out recoil springs according to the loads im using. I have found that the 11lb and 13lb springs arent enough to push the slide all the way into battery. ive always had to change back to the factory captured recoil spring. i think that the pressure from the spring in the magazines is tight and is holding the round in.

Let me know how it works out

[jon49erfan]

people have also said to look at the firing pin block. some of the fss firing pin blocks caused problems like that.

[Sarge]

I found M&P's to be finicky anyway, let alone with that much alteration done at once. Sounds like the light hits are from Out of battery situation. (OOB) It's from mixing and matching too many springs etc. And now to top it off you have a lightened slide thrown into the mix. Good luck getting it figured out. I bet with that light slide you will need to run strong springs.

[thermobollocks]

Got any pictures of your correctly ignited and not correctly ignited brass?

[Ken_Bird]

Ok, here is my view. I own five M&P

When you reduce the slide weight you have to change recoil springs. Most likely an 11#

Next unless this gun was getting light strikes before, then its not the Striker or Spring

You said you did clean the striker and spring chanel, right.

Try removing the barrel from the gun, next take a few of your loaded rounds and see if the will drop in the chamber all the way. Should go in freely.

If that is ok, the your chamber is more than likely fine. With the recoil rod and spring out of the gun will the slide move freely forward and back. This is with the barrel in the gun, just no guide rod and spring. If it goes back and forward rough fix that, if not then remove this slide completely and try another that has not been modified, if that works fine, I would take it to a gunsmith.

JMHO

[kgil275]

Ok, here is my view. I own five M&P

When you reduce the slide weight you have to change recoil springs. Most likely an 11#

Next unless this gun was getting light strikes before, then its not the Striker or Spring

You said you did clean the striker and spring chanel, right.

Try removing the barrel from the gun, next take a few of your loaded rounds and see if the will drop in the chamber all the way. Should go in freely.

If that is ok, the your chamber is more than likely fine. With the recoil rod and spring out of the gun will the slide move freely forward and back. This is with the barrel in the gun, just no guide rod and spring. If it goes back and forward rough fix that, if not then remove this slide completely and try another that has not been modified, if that works fine, I would take it to a gunsmith.

JMHO

+1 I'd also check the barrel hood length for head spacing. When you drop a round in the barrel does the round sit flush with barrel hood? Is it about a finger nail thickness below the barrel hood? Edited December 10, 2013 by kgil275

[Therealkoop]

Id bet 100% the ligth strikes are caused by the FSS. That trigger takes work to get running correctly. You can see my thread on it here:

http://www.brianenos.com/forums/index.php?showtopic=184423

EDIT: sorry didnt see that you already tried removing the USB. You might have to open the trigger bar loop slightly to get the sear to fully disengage off the striker. The sear sometimes downt have enough downward movement and could cause friction/poor relase on the striker. Open it too much however and you will get dead triggers. Try .05 at a time.

Edited December 10, 2013 by Therealkoop

[kend]

Sounds like you have a cluster of problems going on here. First thing, if the extractor is causing the slide to stop you need a stronger recoil spring or the extractor needs to be tuned, an M&P needs all the extractor function it can get and that's why we have extra power extractor springs. Lightening the extrator spring will eventually cause failure to extract issues.

Recoil springs, unless you are doing something completely out of the ordinary you should never need over a 17# spring, if you do there's a severe problem elsewhere that should be corrected (there's a difference in a 17# spring correcting an issue and wanting to / being able to run one). Slide lightening is done so you can run a lighter spring. I have a 5" slide that I lightened (10-ish ozs I think) and I'm running a cut down 11#, it's maybe 9# now. Never a function issue with this setup.

The FSS trigger kit is just that, a kit. All of the parts included in the kit MUST be installed. You can't mix other parts, such as a standard USB, or it will not work. Mine dropped in and I didn't have to change or tune anything.

Now to troubleshooting, as mentioned above the first thing to do is check the headspace. a factory cartridge should be flush or slightly below the barrel hood. If it's belower ( ) than that you may have found the problem. Try a factory barrel and see if it works. If that doesn't fix it, install as much factory stuff as possible and try it, guide rod assy, striker assy, etc. Take the extractor completely out (you'll need a small screwdriver or knife when you shoot it but shoot it single shot to prevent jams). If it runs in the factory configuration start changing one part at the time until it light strikes again. Past that, I wasted a lot of time here. Be interesting to see what you come up with. Email me if you need to borrow some factory parts to try, I may even have a stock barrel.

Edited December 11, 2013 by kend

[Ken_Bird]

Yes, you have some good wisdom written here. I have three M&P with the Apex FSS trigger kit. I installed all the parts in each kit myself. I have sever hundred round shot through them without a problem. You just got an Odd Duck there. I also would love to hear your fix of this. Hey, it could happen to any of us.

[datsthat]

Thank you ALL again for your feedback. I am thinking that my light strikes has something to do with me cutting few coils off the extractor spring b/c prior to the light strikes, my only issue was the slide not returning to complete battery after firing a shot. Cutting coils resolved the battery issue, but now brought on 2 additinoal issues, light strikes & FTExtract. I didn't mention this earlier, but I have had 3 FTExtract since cutting coils. I'll be placing an order for a new extractor spring TODAY.

• I put barrel in slide w/out guide rod & spring on frame and the slides moves back and forth freely.
  Here are pictures of 5 random rounds inserted into barrel. I know its difficult analyzing a picture..how does the fit look?
  
  
  
  
  

• I am using everything in the FSS Kit except the sear plunger spring (using factory).

Heading range shortly. Below is my to-do list for today. Don't know if I will have time to do #3.

1. Swap my KKM barrel for a factory barrel and fire
2. Remove extractor and fire single shot string
3. Re-install as factory parts and fire
4. Take pics of spent brass

[Ken_Bird]

Lets us know the outcome of your test.

[barneyb]

I can't tell for sure, but I don't think those are completely chambering. Try some random samples in both the KKM barrel and compare the same ammo in the factory barrel.

[Therealkoop]

Yeah some of those make it look like the chamber is shallow. Might just be the angle/lighting however.

Opening the shepards hook on the FSS is apparantly a very common thing to do according to Apex.

[datsthat]

Back at work now.

1. Swap my KKM barrel for a factory barrel and fire
   • KKM worked fine in another stock gund
   • Factory barrel had muiltiple light strikes on my gun
2. Remove extractor and fire single shot string
   • Swapped factory extractor and spring and used on my gun, had muiltiple light strikes, but seemed better, but didn't leave it on long enough b/c I had more light strikes than not
3. Re-install as factory parts and fire
   • Ran out of time. Had to get back to work
4. Take pics of spent brass
   • Theres no doubt about it, the striker is hitting off center & not the same spot every time.
     
   • These are rounds with 1 light stikes each. ....off centered strikes
     
     same pics as above except different angle
     
   • Rounds on left took muitiple attempts to fire. Rounds on the right are with 1 light strike each
     
   • Is it bad that the buldge from the striker igniting the primer is not concentric?
     

I think I narrowed the issue down to my slide b/c a factory complete slide worked fine using my frame (I was surprised b/c of the FSS parts in my frame). My frame works fine using factory slide + my KKM + 13# recoil spring. Maybe I didn't install the striker channel correctly? Maybe its not in all the way...I could see this preventing the striker to reach its needed reach to ignite the primer. Put my striker assembly into other gun and vice versa......my gun had many light strikes and the other gun worked fine. Maybe since my slide got Ionbonded, the striker channel is not not in spec? How would I be able to determine

if this is the issue or not? I can't send it to S&W?

Currently using Apex FRE + factory extractor spring + 13# recoil spring & uncaptured rod (doesn't make any difference in light strikes if I use the factory guide rod & springs) + Factory striker & sear plunger spring + FSS Kit (minus sear plunger spring). This combo seems to be the most reliable.

Next trip I plan on

1. Make sure the striker liner is inserted all the way
2. Anyother suggestions?

Edited December 11, 2013 by datsthat

[thermobollocks]

Yeah it kind of looks like you've got an off centered or sloppy striker channel, possibly even at the level of where's it's drilled in the slide.

As for some troubleshooting steps, do you have another striker? Do you have, uh, another slide?

Edited December 11, 2013 by thermobollocks

[Ken_Bird]

Test this. remove the striker and spring from your stock slide. But it in you lightened slide and see what happens. That should tell us about the striker and chanel. Report back... Oh are you shooting reloads or factory ammo?

[datsthat]

Test this. remove the striker and spring from your stock slide. But it in you lightened slide and see what happens. That should tell us about the striker and chanel. Report back... Oh are you shooting reloads or factory ammo?

Sorry, I don't understand you.....Do you mean swapstriker and striker spring from the factory slide with my lightened slide? If so, I have already tried that. stock slide fires fine with either striker and spring. Can you please explain?

Maybe the Striker Channel Liner is out of spec? I think thats more likely than the striker channel out of spec. I'll order a new one.

I am shooting mostly factory ammo, all 115gr (S&B, PMC, Blazer, Magtech, Remington UMC) & only reloads from Washougal River 115 & 124gr

Edited December 11, 2013 by datsthat

[Sarge]

off center hits are also caused by the barrel not being fully into battery.

[datsthat]

off center hits are also caused by the barrel not being fully into battery.

Interesting you said that b/c my 1st issue was slide not returning completely to battery after I fired a shot..

What contributes to the barrel not being fully into battery as I fire a shot?

[datsthat]

Gonna modify striker liner so that it will allow the striker to "reach" further. I'll be back

[thermobollocks]

If it's out of battery and you modify the striker to reach far enough forward to ignite the primer while out of battery, that might cause somewhat of an eyeball integrity event...

[Bluemooncricket]

Given the random placement of the primer hits I would suspect an inconsistent lock up problem, perhaps due to the application of the aftermarket finish. The finish could have made its way into the striker channel as well. When you have a failure to fire, double check that the barrel has completely returned to battery.

[Therealkoop]

The primer hits dont appear random. It looks like they are consistently hiting off center in the same spot, if you clocked the primer strikes all to 12 o'clock they might line up. Ill check when I get home but im pretty sure my M&P doesnt hit exactly centered.

Not trying to beat a dead horse, but if you get frustrated enough to try opening the shepards hook, check post#3 on this thread: http://www.brianenos.com/forums/index.php?showtopic=182297

The idea that the aftemarket finish could be causing issues is something ive seen before also. Could be it.

[datsthat]

Thank you All for the input. I will either modify the striker liner channel or open/close the shepards hook tomorrow and will let you guys know the outcome.

If I can't fix, does anybody have any recommendations on gunsmith? Heck, what about one of you guys? Can I send my slide to you?