M&P 40 Cycling "Delay"

[shotslow]

I shoot limited with a M&P 40 Pro. Often when cycling I get a delayed feel. When this has happened during a match I use Hornady One Shot and the problem seems to go away. Last night I attended a indoor practiced session. The handgun had just been cleaned and oiled with Wilson oil. I had field stripped the handgun. It was a 26 shot course of fire and this "delay" ocurred when the M&P cycled 4 or 5 times. The was no failure to feed or failure to fire. The second time thru the COF the "delay" did not ocurr.

Does anyone have an idea what this is? I checked the striker block by pushing it up and down when cleaning. This "delay" can get bad enough to effect concentration. I don't know another way to describe this. Help, please

P.S. I have a 9mm M&P Pro that has never had this problem. Used it for Limited and Production.

[Jetracer013]

Just a thought, I sometimes ride the slide with my thumbs which causes the slide to slow down dramatically.

[Classic_jon]

One of two things is happening, there is an issue with the slide "sticking" on something and it is actually being delayed or, your brain is going faster than the gun.

I would say to film yourself and see if this delay is perceived or actual. Like the timer, the video will not lie. There are several things it could be...from the complex like the spring is too light... or something as simple as you are riding the slide with your thumbs.

Video will eliminate and answer almost all of these questions in looking at it.

[Dave C]

When you say "delay" are you meaning the slide seems to catch when moving forward? Mine was doing the same thing every once in a while depending on the bullet profile I was shooting. If I rode my slide forward I could induce a three point jamb that could be remedied by bumping the slide forward. I had the issue with SWC and Truncated Cone profile bullets. I never had a problem with round nose. Me, being a 1911 kind of guy, removed my M&P extractor and smoothed up and slightly increased the bevel on the bottom of the extractor hook similar to tuning a 1911 extractor.........no more "delay".

[CHA-LEE]

Video of this kind of issue is needed to effectively troubleshoot.

Based on what you have described it sounds like your are running into a marginal feeding issue where the rounds are nose diving but it eventually recovers and feeds the round. Or the slide lock is getting pushed up slightly so it catches on the slide slightly as the slide comes forward.

Both of these issues can be tested on the bench. For the feeding issue, you can make some dummy rounds of your normal OAL (No powder or Primer) then slide lock the gun, insert the mag, then drop the slide to see how well the rounds are picked up out of the magazine. You can inspect the head of the bullet for excessive dings or nicks and this will tell you if the round is hitting stuff excessively before getting chambered. You also want to recheck the OAL to see if its getting excessively shorter by test feeding the rounds in the gun.

To double check the slide lock lever you can take the slide off of the gun and then push the slide lock lever up then release, it should snap back down with a decent amount of force. Put the slide back on. Push up on the slide lock lever as you pull the slide back so it will catch on the slide holding it back. Then pull back on the slide just enough to disengage the slide lock. The slide lock should disengage with only a very little bit of rearward movement of the slide. If there is not enough spring tension holding down the slide lock lever you will get inconsistent engagement of the slide lock lever while shooting.

[shotslow]

Thanks for the replies. I will do some of that checking. A friend sold me some Rainier bullets real cheap. They are flat points I do not like them but remember the cheap part. Plus buying bullets now is the pits. Doesn't happen with the 9mm where I use round nose, and has never happened. The brain thing has merit. It was a short fast course of fire and I was trying to shoot as fast as I could not caring if I missed. My time, when I felt the "delay", was 2.5 seconds faster than the second time thru.

[bigfish]

The only other thing I think of is maybe if you are using a round instead of a flat wire recoil spring causing binding. I noticed mine would sometimes have a binding feeling at times when racking the slide and everyonce in a while get caught up for a slit second when stripping rounds out of the mag with a round spring.

[shotslow]

I made some dummy rounds. They were short. But they fed ok when I worked the slide. I checked some of the rounds that I was shooting. They were a little short. Most were gone. I think it was the flat point. I have just replaced the recoil spring with a 15 lb. spring. I was using a 13 lb spring. The "delay" thing was more pronounced with the 13 lb spring. I was focused in on a lube problem. Wrong again. I will keep a closer watch on the length. Thanks again.

Shot a club match last weekend. No "delay". Used batch that was 1.125 inches OAL. Had a double feed that destroyed one course of fire. All the rest of the stages were great, except for the classifier, that I won't talk about. It was all me that did bad, can't blame the M&P.

[Gryff]

I've felt this with my M&P40 Compact. I agree that it is probably a feeding issue since it feels like the slide is hanging up on something as it moves forward. It's a distinct feeling.

[partyboy424]

File the edges of your extractor. Sounds like the rounds are jamming up on the way into the barrel. Had this problem on all my m&p 40's with light loads. I imagine its more pronounced in a 9mm