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Discussion Starter · #1 ·
I tried to search online for a parts list chart for a Sig P938, but couldn't find one. I'm wondering, what is the name of this part called and what exactly is it's purpose? I'm tired of it ruining my brass casings with a huge streak across the entire round. Yes I've tested it. I marked the center of the top round with a marker in the center, racked the slide, ejected the round and the scratch is right where the washable marker is at, and there is slight brass deposits on the part I have circled in red which was clean before testing.

I don't have a problem with this in a defensive situation, 9mm is cheap, but when out in the range shooting for practice, I like to save all my brass for future reloading. It puts a dent and ruins the edge of the rim of the round. Rack it enough times to carry it in condition 1 for about a week, and you will have a round with a lot of dents on the rim. Does everyone else's Sig P938 do this? Will I be stuck with this problem on this gun forever? I'm considering just practicing with cheap aluminum and steel rounds and save all my brass for concealed carry on this pistol only.

The last pic, which is hard to see because of how small the bullet is supposed to show a great amount of scruffs and dents on the rim after racking and carrying this gun in condition for one week.

How to replicate:
1.) Place one factory fresh round in magazine.
2.) Rack slide to chamber round.
3.) Repeat with the same round 5-6 times.
4.) Analyze bullet casing and rim for dents and scruffs.
 

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That is the hammer ramp pin. it pushes the top round in the mag down when the slide cycles. You will not get away from this. All semi auto have a hammer ramp which pushes the top round in the mag down. I believe they use this pin for machining reasons.
 

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In his review of the P938 for Guns & Ammo, Patrick Sweeny said this:
Interestingly, the pick-up rail of the slide (that’s the part that strips a round out of the magazine) has a top cartridge control bump. The lump you’ll see under there keeps the top round in the magazine in position, so the violence of the recoil doesn’t cause it to shift around and then cause feeding problems.

Read more: Pocket Parabellum: SIG P938 Review - Guns & Ammo

In his review of the P938 for GunsGunsGuns, Walt Rauch said this:
"Examining the bottom of the slide shows a feature first used on the cartridge pick- up rail of the P238. This is a dome-shaped projection on the bottom forward portion of the rail, and its function, according to a SIG engineer, is to help ensure the last round’s empty case fully clears the gun. As was explained to me, when the last shot is fired and an empty magazine is in the gun, the dome then presses against the magazine follower as the now-empty case extracts and ejects."

Read more: http://gunsgunsguns.net/sig-sauer-p938/
 

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Discussion Starter · #4 ·
I guess this means I'm stuck with this issue. It's a great gun. Perfect size and perfect construction, but not being able to buy, use, and save my own brass without damage is a deal breaker for me since I go to the range weekly. It was nice knowing you sigtalk.com. Off to look for another pocket pistol. Thank you for the help ThnkFrst and Gunnut357s.
 

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Rack it enough times to carry it in condition 1 for about a week, and you will have a round with a lot of dents on the rim.
sigfan001, I've noticed that, after a range session, when I slam the magazine with my defensive rounds, the top round will get marred. But the rim doesn't get dinged up like yours.

How often are you removing the magazine and racking the slide with your defensive rounds? Normally I chamber a round and leave it 'till I shoot again and also leave the magazine in the pistol 'till I get to the range. Then I shoot the hollow point round in the chamber and fire my range ammo for the rest of the session.

The reason I shoot the chambered hollow point is that I've found rechambering will cause cause setback of the bullet, which can dramatically increase pressure in the round. Not a good thing. The round on the left came from a friends pistol and had been rechambered countless times. I didn't let him shoot it.


I think if you rotate the top round out by shooting it you can avoid too much damage, but, like Gunnut357s said, that's probably the only way.

Dave
 

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Discussion Starter · #6 ·
Usually when I carry. At home, I keep a fully loaded magazine in, but not chambered. When I go out, I chamber a round, when I get home, I clear the chamber, and place bullet back in the magazine. Do this enough times and I get those little crimps on the rim, and a huge scratch all across the casing.

Are there any guides on how to remove the hammer ramp pin? I'm curious to see how it works.
 

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I guess this means I'm stuck with this issue. It's a great gun. Perfect size and perfect construction, but not being able to buy, use, and save my own brass without damage is a deal breaker for me since I go to the range weekly. It was nice knowing you sigtalk.com. Off to look for another pocket pistol. Thank you for the help ThnkFrst and Gunnut357s.
I'm a reloader. I understand the obsessive compulsion to try and preserve brass for reloading. Chamber a round, then extract the round to inspect the brass. Shoot a mag, stop pick up brass and inspect it. It became a problem.

You describe the P938 as "perfect size and perfect construction". I feel the same exact way. Over a few months I handled and fired as many of the small single stack 9mm pistols as I could. I settled on the Sig 938 it fit me just right. I won't let the 938 go just because it's rough on brass. It's primary purpose is self defense, not brass preservation. I could give a whit what the ejected brass looks like just as long as the 938 is reliable and shoots straight.

As much as I enjoy reloading, I keep in mind that brass cases are consumable. They can only be resized, belled, and loaded so many times before they can not be used again. I'm always weeding out suspect brass. I'll buy a 100 round value pack of factory ammo to seed once fired brass into my supply. I'll go buy some once fired brass from a gun show or off the internet to seed newer brass into my supply. I'll pick up the brass that others leave behind to seed newer brass into my supply.

What's more important? Having the "perfect size and perfect construction" firearm on you for that one moment it may help save your life or $25 of spent brass that is in good shape for reloading? I won't let go of the perfect CCW pistol for me for the sake of $25 worth of reloadable brass. Call me silly. Maybe I'm the idiot here.

Good luck in buying that less than perfect pistol that is easier on brass.
 

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What's more important? Having the "perfect size and perfect construction" firearm on you for that one moment it may help save your life or $25 of spent brass that is in good shape for reloading? I won't let go of the perfect CCW pistol for me for the sake of $25 worth of reloadable brass. Call me silly. Maybe I'm the idiot here.
I think not.
 

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Discussion Starter · #10 ·
Why not keep the round chambered at home ?
@Fardoche, because I have a shotgun with a very bright flashlight attachment to see better in the dark for home defense.

And thank you JaPes, I hadn't looked at it that way. You bring up very valid points, but I will continue my quest for the best pocket 9mm since this is my only 9mm, and would rather not spend an extra $500 on another gun just so I could shoot 9mm brass without it being ruined by the P938.

And ThnkFrst, keep your jabs to yourself. Didn't your mother ever tell you if you have nothing nice to say, don't say anything at all? Your input added nothing to the discussion.

Thank you all once again for the help, it was nice knowing you guys. Goodbye.
 

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And ThnkFrst, keep your jabs to yourself. Didn't your mother ever tell you if you have nothing nice to say, don't say anything at all? Your input added nothing to the discussion.

Thank you all once again for the help, it was nice knowing you guys. Goodbye.
And what jab would that be?

You asked the name of the part and it's function. I provided an answer to your question and links to some knowledgeable sources. Not sure what else you expected or how I could have added anything more to the discussion.
 

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The ammo manuf recommend only chambering a round 1 time. If you used the same round over and over again and then had an issue, there is no way they would cover it... I agree with others. leave your gun loaded all the time, and when you do empty the chamber, either shoot it out or make that round useless. Your life is not worth the 1 or 2 $ for a new HP round.
 

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I leave mine chambered all the time. The problem that normally arises is the bullet gets pushed back over time and you get too much pressure when it is fired, potentially causing a problem.
 

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I think he said it all with the repeat 5 or 6 times.
Any round chamberd 5 or 6 times will have marks because no one ever designed it for that or thought anyone would do that. Chambering is a violent act.

Bullets are meant to be chambered once and only once. I do that and my brass looks fine.
 

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I looked at some of my spent casings and none have any such marks on them. Even the 147gr defensive ammo left a near pristine casing. They all have a small kink from hitting the side of the frame on the way out, but I think that is normal for a 938.

Fact that he OP has these marks show up on fresh rounds probably indicate his is off nominal spec ?
 

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I haven't seen this issue in over 2,500 rounds.
But if I did, and it was a new 938, it would be going back to Sig with several sample casings. Seems that the 10-15 days gone are worth it to avoid having to sell a gun I like.
 

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I just bought a 938 SAS with a build date of Sept 14'. I have not shot it yet but will in a few days. Racking rounds in and out will leave a line down the brass as well. I can see the brass residue mark left on the hump as well. I also reload, but would have no problem reloading the cases as target brass with a line down them just as long as there is no actual damage to the rim when fired. I will report back after I shoot it and inspect the brass. It does make sense that the slide bump will contact the brass and make some type of mark as it is stainless steel contacting brass. However, contact will seem excessive to me if heavy gauging/pitting in the rim results.

jrprich - what I don't understand is why your cases receive no marks. After all, the purpose of the bump is to slightly push the top round down into the magazine while the empty round is being ejected. If the intended design is working, case marking is to be expected. Not sure why Sig opted for this design when other semi autos accomplish reliable feeding without the slide bump?
 

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jrprich - what I don't understand is why your cases receive no marks. After all, the purpose of the bump is to slightly push the top round down into the magazine while the empty round is being ejected. If the intended design is working, case marking is to be expected. Not sure why Sig opted for this design when other semi autos accomplish reliable feeding without the slide bump?
sootnsmoke,

I didn't inspect all the 2500+ brass my 938 has digested but I have looked at a lot.
I have no idea why mine are not marked like yours. I had a 238 before my 938 and it also produced no readily visible markings on the brass and I think it had the same "bump".
 
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