I have an odd situation with my M&P 45C. First I want to make clear the gun shoots perfectly. My issue is when I press check by pulling the slide back a fraction of an inch the slide sticks which takes it out of battery. My first thought was a weak recoil spring so I installed a new spring guide assembly, but that did not work. The odd thing is it only happens when the barrel is chambered. In other words it will not hang with a mag in the gun and the barrel unchambered. It only happens with a round in the chamber with or without a mag inserted. That leads me to believe there's something going on with the extractor. If anyone has any ideas please let me know. S&W sent me a return authorization, but if it's something I can fix I would be happy to do so. Thanks

My two M&P 45's have chambers on the short end of spec. I've found that depending on bullet shape and weight, the slide can hang just short of battery unless I give it a full "slingshot" to drive the bullet home. I find this shows up most often with SWC and Hollow point bullets that have fatter profiles just in front of the case edge. ( They shoot fine as long as the slide slams them into battery.) Your situation doesn't sound much different. I would suggest:

1) clean the snot out of the chamber to assure there is no lead,copper,or other build-up in there.
2) try different bullet shapes /weights/OAL. Use the "Plunk test" to assure the particular load seats fully in chamber with no force but gravity. ( Google/ search "Plunk Test" if you need help with that.)

Keep us posted.

__________________
Dave

Some very good thoughts. I use a Wilson Chamber Cleaner so I think the chamber is pretty cleaned, but I will check for sure. As far as ammo, the confusing thing is I have been using HST in this gun as long as I have owned it, and this just started happening. Also I'm getting the same results from 230gr Ball ammo. I will do some more cleaning and see what happens. I'm concerned that after holstering this gun it could be out of battery, which is an ugly thought. Thanks

The recoil spring is designed to chamber a round and return the slide to battery with a running start. Possibly after considerable use, the barrel/slide will run in so that it will close when press checking, but that's still not the way the system was designed.

No, the issue doesn't have anything to do with the extractor. Post #2 alleges chambers a bit on the short side. If a local gunsmith has headspace gauges for .45, get him to check the slide & barrel to make sure that isn't the issue. I doubt that it is, but stuff happens. You might also pick up a .45 ACP case gauge to make sure your factory ammo is within spec. It isn't a cheap as the plunk test, but it's to tighter tolerances.

If you absolutely must make sure that the round you attempted to chamber didn't disappear into an alternate space/time continuum , I'd suggest checking the magazine. If it's down a round, the missing round is in the chamber. I'm not trying to be snide here, the concept of the press check-as performed by most folks-is simply hazardous. Check your mags instead.

It appears no one ever told you to place your gun hand thumb on the back of the slide when holstering to make sure the slide stays where it's supposed to. The recoil spring isn't intended to do that either.

Speaking of the recoil spring assembly, the compacts and shield have shorter service lives than the full size guns. The full size guns are 5 years/5000 rounds. I'd sorta expect the compact to go about 3000 rounds......maybe. YMMV.

A 230gr ball should chamber fine. Still, if you do a successful plunk test with the ammo mentioned, you can rule out ALL chamber issues. It only takes a minute.

__________________
Dave

I don't have any 'smith time on these but I've seen autos where the disconnector can cause this kind of issue.

I would suggest that the barrel(s) may need the throat(s) opened just a tad. Many current manufacture auto pistol barrels seem to have either very short throats, or essentially no throat whatsoever. A gunsmith should be able to help, and I can recommend someone who offers this as a specialty if you're interested - reasonable cost, quick turnaround, and quality work.

At this point I have thoroughly cleaned the gun giving special attention to the chamber. It actually seems to be doing better with only a slight drag at the end of the barrel/slide, but it is staying in battery at this point.

One thing I noticed in my inspection was that the ejector seems to be a bit loose, kind of like a loose tooth. My 1911s are all rock solid tight. Please take a look at your M&Ps, and let me know if your ejectors are tight or wobble a bit. I don't know if this has any bearing on my issue or not. As you can tell I'm a 1911 guy, and being that this is my only plastic gun, I'm not as familiar with them as I am with old the slab side. Thanks

The ejector doesn't have anything to do with your issue. While it is supposed to be tight, I've seen quite a few semis with slightly wiggly ejectors that worked just fine. But, those were high mileage guns, yours is relatively new.

Changing the ejector involves messing with the sear block, which must be removed from the frame. Since you already have an RA in hand, why not send it back with a note about the ejector and the chambering issue and let the factory techs look it over.

I agree with Enigma. A lot of current manufacture semi autos of all calibers are short on throat space. Cutting a proper throat can change a finicky gun into one that will eat anything reliably. It takes all of about 5 minutes with a simple hand tool. A chamber gage won't necessarily show this problem, as it's looking for the depth of the case mouth only.

Thanks for the input. Sending it in might be the answer.

My 45C eats everything and is the most reliable gun I have ever owned. Reliability has nothing to do with the easy out of battery issue. It' strictly a matter of having confidence the gun will go bang when I pull the trigger.

You don't indicate whether the gun is new or not....I'm wondering if the drag you're feeling is contact between the foot on the barrel and the camming surface on the breech block? If the gun is new, perhaps the problem will be mitigated by some additional shooting (break in) and some well placed, high quality light gun grease, Like Tetra, for example.

I don't own that particular model, and this comment is not meant as a criticism, but instead of doing a press check, couldn't you just take a look at the loaded chamber witness cavity at the rear of the barrel hood?

To go along with what WR Moore has said, another simple way of confirming the round you just chambered is in the right place is to load only one round in the magazine, insert the mag, chamber the round and then remove the magazine. If the round is not in the magazine, it's in the gun.

__________________
Ret. LE, FA Instr, S&W Armorer

I've owned several automatics that behaved this way. It's really not a defect. On all Browning locking block guns, the last 1/4 in. of slide travel into battery is camming the barrel locking block into its recess in the slide ejection port. Simultaneously the breech face is pushing and sliding on the cartridge head. If there is a round in the magazine its rubbing on the bottom of the slide. Then there's the disconnector actuator or firing pin block sliding into final position. Nothing bad happens unless the slide is gently retracted and eased back into battery without any momentum energy from a rebounding slide with the RSA nearest its lowest force rest position. The extractor hook may also be deflected outward against its spring. If this "defect" hasn't gone away after a few hundred rounds and you can't verify chamber loading by looking in the witness hole, any competent gunsmith could smooth up a few camming surfaces and make it go away.

Does the chambered round not appear in the port machined into the rear of the barrel tab, letting you visually confirm a round has been chambered?

This sort of a self-induced shooter "issue" isn't exactly unusual to experience if someone wants to practice partial slide/barrel manual retraction to confirm a loaded chamber. This is why having a port in the barrel tab can be a handy thing, through which a case rim may be viewed when the slide/barrel is forward in-battery.

Naturally, the factory can still inspect your 45C to make sure nothing is otherwise out-of-spec in some manner.

__________________
Ret LE Firearms inst & armorer

I really appreciate all of the comments, but I probably didn't do a very good job of explaining my issue with the 45C. My gun was purchased by me new in 2011, and has been well used and carried for a long time. The issue at hand has never reared it's ugly head before which is giving me concern.

This issue has nothing to do with cambering or checking to see if I have chambered a round. I only used the press check terminology to describe the issue. The slide will hesitate if gently pushed back with no magazine inserted and a round in the chamber. I can't even remember how I discovered this issue, but one day I was picking up the gun and noticed it was slightly out of battery. As I inspected the situation I noticed if I pull the slide back a fraction of an inch the slide would slightly stick and not go into battery. That's when I began experimenting with loaded mags, unloaded mags, no mags, loaded chamber only, etc.

My concern is that I won't carry a gun that could possibly be out of battery. Battery is determined by a partially chambered round or something blocking movement of the slide which affects the disconnector. My rounds chamber with ease, therefore I sent it off to Springfield today with hopefully a good explanation of what's happening. I'm very interested to see what CS reports about the issue. I'll report back on that hopefully happy day. Thanks again for the comments.

You noted you're a 1911 guy. You need to stop assuming that every other semi-auto pistol operates like a 1911. That slide hesitation you feel as you move the slide rearward is the camming surface on the barrel underlug making contact with the locking block to start pulling the barrel down so it unlocks from the slide. THIS IS NOT AN ISSUE. This is the normal operation of the design, which is similar to that of the Browning High Power/P35.

Likewise, when the barrel moves into battery, the barrel underlug makes contact with the proper part of the locking block to cam the barrel up to lock into the slide.

Now, you do need to realize that the job of the recoil spring is to retard recoil forces until the chamber pressure drops to a proper level, then, from full recoil position, strip a round from the magazine and load it into the chamber while returning the slide to battery position. Holding/returning the slide to battery after you futz with the slide or jam the firearm into a holster isn't in the job description. As noted by several folks, with parts polishing/wearing in from use it may do so BUT YOU'RE NOT SUPPOSED TO DEPEND ON THAT! That's why you put a thumb on the rear of the slide while holstering and avoid press checking.

"Well used" would make me curious how many rounds have been fired through it.

How many times have you replaced the RSA? The usual recommendation to armorers is either every 5 years (of service) or every 5,000 rounds fired.

If the RSA is original, replacing the RSA might return the gun to the original condition before the issue "reared its ugly head.

As WR Moore observed, these newer plastic pistols that have the barrel lugs cam back and down around a locking block, while the rear of the recoil spring may be rubbing against the bottom/rear portion of the barrel, operate a bit differently than a linked 1911 design.

In the Glock line armorers are still taught the field-inspection test of RSA strength ... except for the .45/10 guns which used the wider and heavier slides. Even a brand new RSA may "fail" the field check due to the weight/mass of the slide, meaning the slide/barrel won't return to full battery (when held pointed up) ... and this is performing the check with an empty chamber, and even without a magazine in the gun, meaning there's no top round in the magazine to press up against the slide's pickup rail and offer resistance.

Let us know what the company reports (even if it's just "repaired" or replaced RSA, etc). They might identify something with the barrel and/or locking block that didn't develop into a "problem" until some time has passed (development of spec issue at "wrong" end of normal range). Best to let them inspect it.

Might just be a worn RSA spring, too.

Last I was told in a M&P pistol armorer class, the RSA spring color (paint on several coils at front or rear of captive spring) for the 45C and Mid-size models was Orange. Of course, they can change these things from time to time, and I only hear about it if ordering new parts or attending the pistol armorer classes.

__________________
Ret LE Firearms inst & armorer