300 WSM marks on case shoulder

[screamrider]

I was just inspecting my once fired brass and noticed some odd etching/grooves cut into the base of the shoulder on every case. The marks appear on once fired factory brass (federal in picture) and on my brand new norma brass after the initial reload. This tells me it's nothing to do with my sizing die, since it appears on factory and reloaded ammo.

This obviously must be coming from contact between the case and the chamber from what I can tell. Is this something I should be concerned about?

Rifle is a factory Browning x-bolt stainless stalker 300 WSM. It shoots great, but I'm somewhat concerned about these grooves.

Appreciate your help. Please let me know if you can't see the picture.

https://picasaweb.google.com/108839...&authkey=Gv1sRgCN3F9ruZ57W8Hw&feat=directlink

 

[screamrider]

Just wanted to add that for the reloads I bumped the shoulders back 0.002 inches, and have the 180 grain TTSX bullets seated with 0.050 jump to lands.

Again, I don't think it really matters as the factory federal cartridges have the exact same marks as my reloads.

 

[screamrider]

I'm trying to insert the image directly but I can't figure it out using picasa, sorry.

 

[tailbon3]

I am not a gunsmith but that would concern me. In just a few reloads, your shoulder would likely have some soft spots that might cause the shoulder/neck to split. I think you ought to have a gun smith checkout your chamber and possibly rechamber it.

 

[Bill Johnson]

So here's the case:


My best guestimate is about .002 to .003 deep, which puts it in the 10% of wall thickness range. That's generally acceptable and you shouldn't have problems with case life but there's no guarantees. It's rough reamer marks. If there's no raised material on the case, the chamber can be polished out and the marks will go away. If there is some raised material, the chamber can still be polished, the damage will be reduced but will still mark the case.

It looks minimal to me but that's just going off one photo and the damaged area is blurry. Have a competent gunsmith look at the chamber with a borescope and determine the best course of action. Worst case is as already been mentioned, the barrel set back a thread and the chamber recut.

Hope this helps.

 

[screamrider]

So here's the case:


My best guestimate is about .002 to .003 deep, which puts it in the 10% of wall thickness range. That's generally acceptable and you shouldn't have problems with case life but there's no guarantees. It's rough reamer marks. If there's no raised material on the case, the chamber can be polished out and the marks will go away. If there is some raised material, the chamber can still be polished, the damage will be reduced but will still mark the case.

It looks minimal to me but that's just going off one photo and the damaged area is blurry. Have a competent gunsmith look at the chamber with a borescope and determine the best course of action. Worst case is as already been mentioned, the barrel set back a thread and the chamber recut.

Hope this helps.

Really appreciate your help Bill!

Looks like I may have just pinpointed the problem. I tried chambering some of the twice fired federal cases I was using and noticed some excessive friction just prior to ejection (going very slowly). After playing with several pieces of brass and working the bolt back and forth so that the shoulder was continuously rubbing on the inside edge of the ejector port, I noticed it was making the grooves.

I attached 4 pictures to get a second opinion. The grooves are obvious on the case, and you can see in the one picture from inside the magazine slot that there is a very rough section of metal causing the damage (at least I think it is). You can even see some metal shavings in the one picture after cycling the bolt about 5 times.

Has anyone seen this before? Seems like something most smiths could fix? I don't want to start filing anything myself, that's for sure.

My best guess is that one ejection cycle of a hot casing is enough to cause the grooves that I posted originally (the brass colored norma case)

https://picasaweb.google.com/108839...&authkey=Gv1sRgCPPPh4bJhI-XXw&feat=directlink

Can anyone explain how I can just insert an image as opposed to linking it?

Thanks!

 

[LoneTraveler]

I looked at the first picture, and these. My first question was the shells placed in the magazine and then bolted into the chamber? Also was the case coming in contact with part of the action on extraction and ejection. Take a case and coat it with a magic marker. Start with the magazine if you use it. when the shell comes out of the magazine, Check it. Then load and fire a shell. When extracting the case use a finger to keep the case from dragging on any of the action until it is free of the action and check for scratches. Then shoot and extract and eject normal cycle and compare cases. My thought is there is a sharp edge on the magazine lips or on the chamber edge or inside the action that the case is being pulled across. As a Police armor in 15 years I went through 3 semi-auto pistol changes with 21 officers. A Dremel tool and a fine grinding stone and a Bright Boy Stick (abrasive imbedded in rubber that mounted on a screw tip mandrell) cleaned up rough sharp edges so the pistols would work flawlessly. Good Luck

 

[LoneTraveler]

Those marks do not look like they are from the chamber. Those marks looks like the case is dragging on a burr, Either from the Magazine lip or as the case is extracted it is dragging in the action. A Dremel tool or a Ice cream stick with some glued on Emory Cloth should remove the problem burrs. Good Luck

 

[screamrider]

I looked at the first picture, and these. My first question was the shells placed in the magazine and then bolted into the chamber? Also was the case coming in contact with part of the action on extraction and ejection. Take a case and coat it with a magic marker. Start with the magazine if you use it. when the shell comes out of the magazine, Check it. Then load and fire a shell. When extracting the case use a finger to keep the case from dragging on any of the action until it is free of the action and check for scratches. Then shoot and extract and eject normal cycle and compare cases. My thought is there is a sharp edge on the magazine lips or on the chamber edge or inside the action that the case is being pulled across. As a Police armor in 15 years I went through 3 semi-auto pistol changes with 21 officers. A Dremel tool and a fine grinding stone and a Bright Boy Stick (abrasive imbedded in rubber that mounted on a screw tip mandrell) cleaned up rough sharp edges so the pistols would work flawlessly. Good Luck

I will absolutely try what you're saying with the magic marker over the entire case, thanks for the tip!

To answer your question, no, I did not use the magazine at all. I loaded all rounds directly through the ejection port.

Did you see all 4 of the pictures from my last post? I think you're right, in that the cases are dragging on the sharp edge of the action, on the inside lip of the ejection port. I tried to show it with a red circle in the pics.

If I try your magic marker trick and control the fired case with my finger on ejection, that should stop the case from dragging on that part of the action, thereby confirming the problem. Unfortunately I won't be able to get to the range for 2 weeks.

On another note, would it be advisable to size and use these cases again (the norma cases from the first pic, not the really beat up federal nickel plated cases from the series of 4 pictures). I hope so, they're brand new (only fired once) and were pricey!

As Bill mentioned I think it's fine from a safety standpoint, but I'm wondering if firing the grooved cases could damage the chamber when the brass expands at the shot. Pretty sure it wouldn't, but would appreciate some experienced opinions.

I'll get my gun to the local smith to smooth out that suspect part of my action.

 

[screamrider]

Those marks do not look like they are from the chamber. Those marks looks like the case is dragging on a burr, Either from the Magazine lip or as the case is extracted it is dragging in the action. A Dremel tool or a Ice cream stick with some glued on Emory Cloth should remove the problem burrs. Good Luck

Hmmm, I may consider tackling this myself.....the emory cloth popsicle stick sounds relatively easy, yet hard for me to mess up and do damage.

 

[Bill Johnson]

Hmmm, I may consider tackling this myself.....the emory cloth popsicle stick sounds relatively easy, yet hard for me to mess up and do damage.

I absolutely think you can handle that. You can use lady's fingernail emory boards and I doubt you could possibly sand away enough material from that action to cause any problem. I'd probably attack it with a round Swiss file first then smooth it out by wet sanding with a piece of 400 grit aluminum oxide paper rolled up to a diameter similar to the cartridge case. Just use something round so you're only removing material from that spot. Use any oil to wet sand. Clean the action thoroughly after.



I looked at Picassa and it doesn't appear to be a way to post pictures to forums from there. I use Photbucket. It works pretty good these days.

Good luck!

 

[Deleted member 46119]

"softening" edges in the action ejector port with fine emery paper/stick and or wet+dry is a fine idea.

Have you determined if it's on feed or extraction?

If not, I have a "procedure" for you.

Chamber a case by hand being careful not let it rub on anything.

Extract the case slowly and when you can see the brass, use your finger to push the brass away from the ejector port so it can't rub where Bill labeled the picture.

If there are no marks, that is the culprit. Probably is anyway.

 

[screamrider]

"softening" edges in the action ejector port with fine emery paper/stick and or wet+dry is a fine idea.

Have you determined if it's on feed or extraction?

If not, I have a "procedure" for you.

Chamber a case by hand being careful not let it rub on anything.

Extract the case slowly and when you can see the brass, use your finger to push the brass away from the ejector port so it can't rub where Bill labeled the picture.

If there are no marks, that is the culprit. Probably is anyway.

I'm 99% sure it's on extraction. I just started reloading and and have fired 50 of my own loads so far, and each one I chambered individually through the ejection port and not from the magazine.

LoneTraveler recommend the same procedure are you I believe, and I will definitely give it a try to confirm the issue is on ejection. Thanks for the great tip!

My only questions now, are:

1. Can I re-size the norma brass (once fired) that has these marks, or could it damage my die?

2. Assuming I can do number 1 without damaging my die, is there any risk of damaging my chamber with these marked cases?

 

[screamrider]

I finally got photo bucket up and running.

Here is the suspect edge doing the damage:

View from inside the magazine feed:

Damage to the case: