Extractor marks on brass

speedfreak · #1 07-27-2013, 02:09 PM

After shooting my first reloads at the range and carefully inspecting the brass I noticed small rectangle indents above the rim where the extractor grabs the brass. They seem to occur from the lower charge all the way through to my max(52gr of IMR 4350,0.5 from max book value) but not consistent in depth and in no correlation to powder charge. I checked a bunch of factory winchester supreme and some of them also exhibit this. Anyone else ever notice this? Is it normal? The back of the casing is clean, no ejector marks and the brass chambered and extracted with no issues.

Dick284 · #2 07-27-2013, 03:31 PM

Pics?
Rifle?
Cartridge?

speedfreak · #3 07-27-2013, 04:45 PM

Sorry, I guess I forgot the details. Rifle is a 270 Win browning X-bolt. Pics are below.

It's a little hard to see but you can make out the flat indent. I tried to pic the most visible one so it would show.

deanmc · #4 07-27-2013, 04:54 PM

Man that is hard to see on my antique computer. Did you mic the cases after shooting and how do the primers look?

speedfreak · #5 07-27-2013, 04:58 PM

Yeah it's pretty hard to see. I will see if I can edit the picture to zoom in and get it to show up a little better.

The primers look pretty much the same from the starting load to the max and look similar to factory. I think they all look a little flat but people with way more experience think they are okay. Here are some factory shots.
http://www.outdoorsmenforum.ca/showthread.php?t=180855

I don't have a mic but do have digital calipers. Would these be accurate enough to bother measuring the case?

deanmc · #6 07-27-2013, 05:04 PM

Quote:

Originally Posted by speedfreak

I don't have a mic but do have digital calipers. Would these be accurate enough to bother measure the case?

Yes they should be.

speedfreak · #7 07-27-2013, 05:14 PM

Just a FL sized case measure 0.466 and these second fired ones measure 0.4665. Not sure if that digit is actually accurate though.

speedfreak · #8 07-27-2013, 05:18 PM

Not sure if this is better for anyone.

Lefty-Canuck · #9 07-27-2013, 05:23 PM

IMHO looks fine, when you say "extractor marks" I picture (in my head) a pressure sign on the case head face that is either an indentation or an extra shiny part from where the extractor pin had to drag partially across the face of the case head.

LC

260 Rem · #10 07-27-2013, 05:25 PM

Quote:

Originally Posted by speedfreak

Just a FL sized case measure 0.466 and these second fired ones measure 0.4665. Not sure if that digit is actually accurate though.

Hand loaders should all make a trip to London Drugs and pick up one of the little cup style magnifiers used for map reading. They are great for looking at primers...the edges of primers show up well and it is easy to notice when the shoulders start to lose their bevel. They also show up any cratering around the firing pin indent which MAY also be indicative of pressure.
The shinny marks you don't want to see on the base of your brass are the ones made by the ejector pin.

speedfreak · #11 07-27-2013, 05:28 PM

I actually have one of those magnifiers. I haven't ever seen "hot" load in real life though only internet pictures. I might be confusing people with my terms. Not sure if they are correct or not but I refer to the hook that removes the case as the extractor and the circular round part in the bolt face as the ejector. The are no marks in the case head. Please correct me if I am wrong, I like to use the correct terms if possible.

Lefty-Canuck · #12 07-27-2013, 05:42 PM

Quote:

Originally Posted by speedfreak

I actually have one of those magnifiers. I haven't ever seen "hot" load in real life though only internet pictures. I might be confusing people with my terms. Not sure if they are correct or not but I refer to the hook that removes the case as the extractor and the circular round part in the bolt face as the ejector. The are no marks in the case head. Please correct me if I am wrong, I like to use the correct terms if possible.

Chamber an empty case.....then extract it as forcefully as you would a fired round, look for the extractor mark....is it similar?

LC

gitrdun · #13 07-27-2013, 05:50 PM

Quote:

Originally Posted by Lefty-Canuck

IMHO looks fine, when you say "extractor marks" I picture (in my head) a pressure sign on the case head face that is either an indentation or an extra shiny part from where the extractor pin had to drag partially across the face of the case head.

LC

You mean ejector? I don't see indents on the case heads from the ejector bore. It looks to me as he may simply have a rough spot on the extractor claw. That indent looks pretty nasty though, but it could just be lighting playing tricks on the photo outcome.

speedfreak · #14 07-27-2013, 05:54 PM

I actually don't have an virgin brass. I found one once fired that didn't look to have any marks on it. I tried to chamber and eject it like I would a normal case and it looks like it left a smaller less visible mark than the others it was much harder to see.

gitrdun · #15 07-27-2013, 06:05 PM

Take a good look at you extractor claw with a magnifying glass. It may just be as simple as removing the extractor and smoothing it with a fine file. Just my 2 cents for what it's worth.

gitrdun · #16 07-27-2013, 06:10 PM

Quote:

Originally Posted by 260 Rem

Hand loaders should all make a trip to London Drugs and pick up one of the little cup style magnifiers used for map reading. They are great for looking at primers...the edges of primers show up well and it is easy to notice when the shoulders start to lose their bevel. They also show up any cratering around the firing pin indent which MAY also be indicative of pressure.
The shinny marks you don't want to see on the base of your brass are the ones made by the ejector pin.

I would like to correct that if I may. The ejector pin is retracted on bolt closure when the gun is fired, and is released upon opening the bolt and ejection. The shiny mark you refer to is caused by the hole from which the pin protudes. It is indeed a sign of high pressure as the casing is jammed back with great force against the bolt face and the brass flows into the pin hole.

speedfreak · #17 07-27-2013, 06:23 PM

After looking at my extractor and the size of the indent I thing I know where it is coming from. I never really paid attention to the bolt face in great detail until last week. I noticed the ejector is not straight across and the only picture I could find from the internet showed it the same. I asked about it but I guess no one had an xbolt handy.
http://www.outdoorsmenforum.ca/showthread.php?t=185658

If anyone does is this normal?

When I first look at it I thought it was bent but wouldn't it more likely break than bend back like that? I guess I could always go to Cabela's and get then to pull a bolt for me to look at.

Bobby B. · #18 07-27-2013, 06:37 PM

Quote:

Originally Posted by gitrdun

You mean ejector? I don't see indents on the case heads from the ejector bore. It looks to me as he may simply have a rough spot on the extractor claw. That indent looks pretty nasty though, but it could just be lighting playing tricks on the photo outcome.

My thoughts exactly. It appears as though there is some, damn, I can't think of the word at this moment. Sculling? Scalding? Oh, yes, galling. In a practical sense, nothing to be concerned about in so far as safety is concerned.

What appears to be happening is the extractor claw is digging (galling) into the extractor groove in the case. Not a good thing, but not a dangerous thing by any means.

Could be the rim thickness of youir cases is slightly greater than the gap/space in the extractor so it's carving into the case a bit.

Same thing happend in a 30/06 Husqvarna I had.

Bobby B.

gitrdun · #19 07-27-2013, 06:39 PM

I don't have an X-bolt here, just an A-bolt which is a bit different. But I do see what appears to be quite a bit of brass deposit on the inside shoulder of you extractor claw. That 45 degree (or so) corner on it seems a bit odd, perhaps design I'm not sure. And you can you determine if that corner is broken off or design? That build up of brass on the inside shoulder cannot be helpful. I would still tpull that extractor and clean it.

Bolt maintenance and cleaning is often disregarded by a lot of shooters, shouldn't be though.

gitrdun · #20 07-27-2013, 06:41 PM

Quote:

Originally Posted by Bobby B.

My thoughts exactly. It appears as though there is some, damn, I can't think of the word at this moment. Sculling? Scalding? Oh, yes, galling. In a practical sense, nothing to be concerned about in so far as safety is concerned.

What appears to be happening is the extractor claw is digging (galling) into the extractor groove in the case. Not a good thing, but not a dangerous thing by any means.

Could be the rim thickness of youir cases is slightly greater than the gap/space in the extractor so it's carving into the case a bit.

Same thing happend in a 30/06 Husqvarna I had.

Bobby B.

Agreed Bobby B.

260 Rem · #21 07-27-2013, 06:44 PM

Quote:

Originally Posted by gitrdun

I would like to correct that if I may. The ejector pin is retracted on bolt closure when the gun is fired, and is released upon opening the bolt and ejection. The shiny mark you refer to is caused by the hole from which the pin protudes. It is indeed a sign of high pressure as the casing is jammed back with great force against the bolt face and the brass flows into the pin hole.

Thanks gitr....I thought the brass actually hit the plunger/pin.

speedfreak · #22 07-27-2013, 06:46 PM

Could just be the picture, its probably just dirt and grit which I will clean out. I shoot winchester supreme 99% of the time and they are all nickel plated. The corner is actual no broken off just bent back which makes me think its by design but I'm not sure. In the first picture you can kind of make out where the crease is and the metal bends back. Its hard to make out if you haven't seen it in person though. Thanks everyone for looking and giving ideas!! If I could find some 270 brass I would just try and see if its the cases or the plating. It just happens that I have a bunch of these from before I decided to reload.

gitrdun · #23 07-27-2013, 06:47 PM

Now that I look at the pictures again, I see another tell tale sign. The bottom picture shows a ring of brass at the bottom of the bolt face recess. I believe that brass is scraped off the case extractor groove by the extractor claw. It is left deposited inside the bolt face. On the next and subsequent firing, the casing is forced back against the bolt face and crushes the reaming brass remnants in a neat ring on the perimeter of the bolt face shoulder. Dismantle your bolt, give it a thorough cleaning, scraping all brass remnants away and inspect the extractor claw for roughness, uneveness etc.

speedfreak · #24 07-27-2013, 06:55 PM

Unfortunately I haven't been able to find much on bolt disassembly on the net and I'm not sure I'm confident enough to start pounding pins outta it. Might have to take it in.

gitrdun · #25 07-27-2013, 06:59 PM

Quote:

Originally Posted by speedfreak

Could just be the picture, its probably just dirt and grit which I will clean out. I shoot winchester supreme 99% of the time and they are all nickel plated. The corner is actual no broken off just bent back which makes me think its by design but I'm not sure. In the first picture you can kind of make out where the crease is and the metal bends back. Its hard to make out if you haven't seen it in person though. Thanks everyone for looking and giving ideas!! If I could find some 270 brass I would just try and see if its the cases or the plating. It just happens that I have a bunch of these from before I decided to reload.

I truly believe that your extractor claw should not be bent back by design. If so, it would be a first for me. I believe that it is either bent back from a previous incident or by design fault or weakness. If it were my rifle, I would grind or file off that bend and give it a whirl. Even if you remove it, you still have an extractor and your gun's safety aspect will not be compromised.

gitrdun · #26 07-27-2013, 07:02 PM

Quote:

Originally Posted by speedfreak

Unfortunately I haven't been able to find much on bolt disassembly on the net and I'm not sure I'm confident enough to start pounding pins outta it. Might have to take it in.

Good idea if you don't feel comfortable. It's a half hour job and shouldn't cost you too much for peace of mind.

Most people are freaked out by bolt disassembly.

Good luck bud.

silver · #27 07-27-2013, 07:51 PM

Now bear with me on this, by the photo you have your extractor impinging on your brass. So my question is what is the diameter of your bolt across your extractor? If you insert a case into the face of your bolt, what is the diameter of your bolt then? Just a thought.

speedfreak · #28 07-27-2013, 08:54 PM

Silver, not exactly sure what measurement you are looking for. With nothing in the bolt it measures 0.446 to the edge of the extractor and 0.486 across the entire bolt face. These are inside diameters. With a case inserted the outside diameter doesn't change as the case doesn't push the extractor far enough against the spring to make it stick out past the side of the bolt.(not sure if that made any sense?) It measures 0.672 in both cases.

speerchucker30x378 · #29 07-28-2013, 09:26 AM

Dan, as per your email.

If I have to actually book something in and put a tool to something its a $100 minimum. If I just look at something and tell you not to worry and go out and play I charge nothing.
I am almost 100% certain that it is what we call in the industry "an acceleration or shock mark mark." Its obviously left by the extractor, a monkey can see that, but obviously the extractor spring does not have near enough power to cause the mark. That's where the monkey gets confuzzled. When the gun is fired the barrel makes a god awful whip as the bullet accelerates and turns in the barrel and that whip is transferred to the action. Also, the bolt and receiver are often a bit out of alignment on hunting rifles and as pressure comes up these parts straighten out, crash around and the case which is smaller than the chamber expands violently against the chamber walls and extractor. Watch a few of the slow motion Mpgs of guns being fired on YouTube and you will get the idea. Basically when all this is going on enough kinetic energy is generated to imprint the extractor claw into the soft brass and create a small but mystifying flat or cut. In this case its nothing to worry about and causes no damage. It's quite common. It can however be a "bite mark". This is caused by the extractor hitting the barrel face on closing and pressing the claw into the brass. This while by no means dangerous, can have a detriment to accuracy and should be corrected.

Rod Henrickson

ADD NOTE: I think Pud, at Bashaw sports does Browning warranty. He would correct it for free. I of course charge money.