S&W Shield .45

[lightload]

On my new Shield .45 I noticed scalloped machine marks on the slide's bottom surface--specifically that long ridge of metal that contacts cartridges in the magazine. Retracting the slide with a loaded mag produce a grinding sound as these marks moved across cases. When I talked with a Smith customer service person, he said that all 45 Shields have these machine marks, and their purpose is to retard slide velocity. I have never heard of this method to reduce slide velocity and am not comfortable with it. Some of you guys are machinists and engineers and gunsmiths. Others here also are knowledgeable. What are your opinions on using machine marks on the slide to slow down slide velocity?

[10-x]

Have not noticed those end mill marks= poor machining on mine, will have to check. Would think spring tension would be the method to slow down the slide? What say you?

[lightload]

I agree 100%. When you consider that upward force against the slide will decrease as fewer and fewer cartridges remain in the magazine, I don't understand how this approach would be effective. I've polished these marks lightly to lessen the grinding as slide retracts. I can tell no difference in slide velocity.

[10-x]

IMHO the answer you got was kind of bs. Why would the slide grinding one side of a case make sense? Long gone are the days of finish machining, just spit them our fast as possible. Will take mine apart today and check. Have friends with 9's and 40' s, I' ll ask them about it.

[castalott]

The only method I know of to reduce slide velocity was John Browning's 1911 feed ramp which supposedly slowed the slide so it didn't 'whack' home. ( I believe this as I ,when younger and dumber, would single load rounds into the chamber and press the slide release. The slide would smack home (overriding the controlled feed of the extractor too!). One day I did this and the 'smack' sheared the hammer surfaces off and the gun went Boom! Right thru a kitchen chair and into the floor....

I doubt these machine burrs are meant to do that. But I've been wrong about other things...

[Texas by God]

Interesting. I will check our 9&40 Shields as well. I would think the .40's slide velocity would be the fastest anyway. I call BS on the CS.

[bedbugbilly]

I'm not seeing them on my 9mm and I haven't had the chance to take a look at the 45 Shield or handle one even. But I agree with 10-X. I think you got a bs answer from them. Anybody who has ever run a mill knows that increased feed without increasing rams of cutter = machining marks but it also increases parts per hour.

My question would be - and I am by no means an expert - but what happens when thousands of rounds are put through and those "special" slide marks wear down? Are you going to have to send it back and have the slide replaced because the slide velocity is now too great due to the wear?

I like Smiths and I really like my 9mm Shield - enough that I'm considering getting a 45 but I have to wonder if the quality of the machining may not be suffering a little in order to meet production demands and sales demands?

If it is otherwise though, I for one would like a more detailed explanation from the factory. I would think that this would be mentioned in all the reviews that have been done on this particular pistol.

[lightload]

My 9mm Shield does not have these marks. I googled the issue with these marks occurring in Shield 45's, and they are reported, and reducing slide velocity has been quoted as the reason. You can definitely feel the drag on the first round in the mag. If Smith engineers made this decision, then I wonder where their heads were. Anyway, I've already polished them lightly.

[10-x]

Finally got around to taking mine apart. The semi circle marks are from an end mill at about 20 degrees, just " kissing" the bottom of slide and are deliberate. Mine were half full of brass!! Have to check the cases from it. Confused and disappointed in such a design. First question is once the marks are full will the cycle be to fast and cause a problem or damage???? Thoughts and comments....

[Texas by God]

Both my 9&40 show no marks.

[lightload]

I don't see how the marks being filled or in my case polished would cause damage. I choose to believe that they do not effectively slow down slide velocity and consider them a poor idea. Of course, that's my opinion. Another opinion is that Smith opted not to use a stronger recoil spring because some people might have had difficulty retracting the slide. Perhaps the factory feared that +P ammo would cause a problem with the current spring and used this machine mark method. Or, maybe Smith's aim was to reduce felt recoil. Anyway, I'm not please with the arrangement.

I plan to contact Speed Shooters and talk to them about getting a heavier recoil spring and continue to polish this area. Also, I plan on talking with Smith's technical services to learn more about their reasoning.

[Dryball]

Customer service rep didn't know ****. Ask to speak with a tech. Most of the time when deliberate marks are used they are to accept and keep carbon from building up...but it seems an odd place where you are describing. Any pics? The only other reason I can figure is bling. Don't Shields have the scalloping at the rear/side of the slide?

[lightload]

The Smith and Wesson forum has a post showing a picture of these marks. The link that I gave was not valid so I deleted it. I apologize.

[10-x]

Talking aboui stiff springs, the magazine springs in .45 Shields are the hardest Ive ever loaded, much stiffer than any submachine guns. The end mill semi circles are disturbing in the design, I also ask, where were the engineers heads? Is pot legal up there,LOL!!!

[bedbugbilly]

So . . . I go back to my previous post. IF the marks are intentional and this is the engineer's design . . . over time and a lot of rounds, will these marks not "wear" or as already mentioned by `10-X, fill with brass - that will certainly affect the "velocity"of the slide (I would think). So what is S & W going to do? Are they going to replace the worn slides with new slides that have this "special" machining?

I really am not trying to be critical or anything else - I just find all of this interesting and hope the real answer surfaces at some point. I have a 9mm Shield and have/had plans on picking up a 45 Shield at some point in the near future. But, it this is how Smith is engineering that particular Shield, it is going to give me good reason to look at other makes/models.

Just as a "casual comment" . . .I think there are a lot of "theories" and "explanations" circulating about these machining marks and if so, then perhaps S & W Engineers should be addressing it in a forthright manner and be explaining them. I think it is odd that some have them and others don't? That is what leads me to believe it is a drop in their QC to meet production needs . . . but I've been wrong about a lot of things over the years and I may be on this as well?

[10-x]

The semi circle end mill cuts are deliberate, evenly spaced ,same depth and in center of bottom section of slide. A logical explanation would be nice. Grinding the side of the cartridge case to slow down slide is not logical, at least to me. Will have no problem selling it if it comes to that. Will be looking for a similar sized .45?

[lightload]

I just now got off the phone with a gentleman who answered the phone in the M&P technical service area(?). When asked the magic question about the machine marks, he replied that they were there to help the gun run smoother. Pressing him further, I got him to call "somebody" to find out more and from this I was told that the cuts help move the bullet along. When I asked again about reducing slide velocity, he said definitely not. The conversation gave me the impression that he was not up to date or well informed. At this point, I don't have a clue.

[10-x]

Took mine to friend that has a 9 and a 40, took it apart and 3 of us looked at the marks, no logical explaination. All agreed on whats going to happen when these " divets" are filled with brass??? Guess one thing is clear, dont want to shoot it very much, after all its a short range self defense firearm......

[lightload]

I remain confused but still like the pistol. Thinking back, I remember that in some semi auto pistols the top round will move forward in the case--sometimes to the extent that removing the mag will cause the round to hang. I noticed that in the 45 Shield, this event does not occur. Perhaps the marks prevent this forward movement even if this was not their purpose.

Randy is a machinist. Perhaps he will offer an opinion.

[Texas by God]

I judge all "Little .45s" by the defunct Star PD. Nothing has come close yet. My opinion based on my experience. Best, Thomas.