Spent cartridge markings.

Georgezilla · Post by **Georgezilla** » Tue Nov 13, 2007 9:57 pm

Today at the range I was doing some shooting with my Mk3 Hunter at 50yards using a sand bag rest. So of course when I was done shooting there were lots of spent cartridges about the table, naturally I took a look at them to see if everything was on the up and up, heres what I saw:

As you can see there is a V shaped powder mark with a short tool mark in the middle of these cartridges. These powder marks and tool marks are only on the extractor side of the cartridges (I think the extractor has something to do with the tool mark). Aside from what you'd expect from being put in and out of the chamber the sides of the cartridge facing the LCI, magazine and firing pin look clean and have no tool marks as distinct as the ones on the extractor side of the cartridge.
Other than this the cartridges looked normal, didn't seem to be bulged more than normal, no cracks. I even shot some pretty good groups with it

So are these normal powder/tool marks? My untrained eyes have no clue! I figured it's better to be safe than sorry, and even if it's nothing I'd like to know what causes the powder burns and tool marks. Almost forgot to mention, I was mostly using CCI Standard Velocity. I tried Federal Bulk, Federal Auto Match and CCI Blaizers to see if they made the same markings and they did.

Thanks!

Post by **Bullseye** » Tue Nov 13, 2007 10:40 pm

The powder marks are normal. I can't recall seeing any of the tool scrape marks before but they do not look excessive. Is there a burr in the extractor channel that extends into the chamber? This is about all I can think of that could make that type of mark. If it was on the LCI side then I'd say the metal tab was making the mark but this is on the extractor side.

Can you post another shot with the bottom of the case facing frontwards and the powder burn/scrap visible down the side in the distance?

R,
Bullseye

Georgezilla · Post by **Georgezilla** » Wed Nov 14, 2007 4:03 pm

Sorry for the poor picture quality. I'm gonna try and get a new battery for my good digi camera (which can actually take decent close ups) this week.

I think you are right about the extractor channel making the mark, heres a picture of the chamber face (the arrow is pointing at what I think may be the cause). After you see the picture I'll edit the size, any smaller and what I think is the burr doesn't come out clear.

The position of what seems to be the burr appears to match the position of the tool mark on the cartridges.

Post by **Bullseye** » Wed Nov 14, 2007 9:05 pm

Your pictures are perfect. I can see the alignment of the firing pin hit in relationship to the mark on the case. It is clearly coming from the region of the extractor groove. You can take a pointed punch and lightly tap it inside the chamber mouth and swage back that burr. Or you can carefully use a round Jeweler's file and with a couple of light strokes remove the burr. The good news is it is very slight but it could affect cartridge seating and detonation, especially when the chamber gets fouled. It is already affecting the case seal at detonation, as evidenced by the residue pattern on the case, and this is allowing a little blowback to reach the chamber wall. That blowback will eventually build up and could cause misfires. Keep your chamber clean and misfires should be held down to a minimum.

Hope this helps.

R,
Bullseye

Georgezilla · Post by **Georgezilla** » Thu Nov 15, 2007 12:41 am

Interesting. I had been thinking that the powder residue on the chamber face was a bit excessive, but I never had any problems so I figured it was normal. I probably never had any misfires because I kept it so clean, I never go to the range without it being clean

Do you think taking care of this burr will resolve the blowback, Or could there be more at work deeper in the chamber? The reason I ask is because if you think theres a decent chance that theres more at work I will probably just send it to Ruger.

Thanks.

Post by **Bullseye** » Thu Nov 15, 2007 6:16 am

The blowback marks are not excessive. I get far worse in some of my Model 41's. The cases are supposed to seal the chamber off during detonation and combustion but it takes a few microseconds for this to happen. Typically some cases get scorch marks on them and a little powder residue gets by. This is one reason why cleaning the chamber frequently with a brush is important with a rimfire pistol.

The correlation between where the scorching and gouge marks are located on the spent case is relevant. That mark appears fairly centered in the carbon burn pattern. This observation tells me that they have a common source.

If you're unsure about applying a small file to the burr then I can understand the rationale for sending it back to Ruger. But I'm only suggesting that you use a few light strokes with the file to remove the burr off of the chamber mouth's chamfered edge. Then you can test again to see if the gouge has been removed and what the case looks like after retesting. Ruger can apply a chamber reamer to the barrel and clean up the burr in a snap but that still would take considerable time for shipping and handling. If you do decide to send it back - be sure to include some of those spent cartridges for them to inspect.

If you decide to give it a go and remove the burr yourself, then you'll still have the option of sending it to Ruger if you're not satisfied with the results. If you do file, just take care not to let the file touch any of the other parts of the chamber or the barrel's rifling.

I wouldn't be concerned if you get the burr out but you still have scorch marks. As long as the pistol functions 100% those hot gas marks aren't something to be worried about. Keep it clean and you'll run fine.

Hope this helps.

R,
Bullseye

Georgezilla · Post by **Georgezilla** » Thu Nov 15, 2007 3:48 pm

Thanks for the information. This weekend I'll go pick up a Jeweler's file and take care of the burr with it. I plan on going out to the range Saturday or Sunday, so I'll post post an update then.

Thanks a lot for the help

!

Georgezilla · Post by **Georgezilla** » Mon Nov 19, 2007 1:25 am

Well I went out to the range with a Jewler's file in hand today. unfortunately I was in a bit of a hurry and did not have time to fully resolve the problem (I was only there for about 30 minutes

). Heres as far as I got:

I'm not at all familiar with working steel in any manner, with that being said I think I wasn't using enough pressure when I was filing. I did a couple light strokes two separate times and the marks on the cartridges looked the same as they did before. Finally I took the pistol apart the third time and filed with a bit more pressure and the marks seemed to get smaller.

So does it look like I'm on the right track? Thanks.

Post by **Bullseye** » Mon Nov 19, 2007 6:54 am

Those look fine. The scratch is almost gone. Shoot it for a while and see how it functions before removing any more of the burr.

R,
Bullseye

Georgezilla · Post by **Georgezilla** » Fri Nov 23, 2007 2:57 am

I went out to the range yesterday (After eating 3 times in 5 hours

Hope you all had as good or better Thanksgiving than I!) fired a magazine, after inspecting all 10 cartridges I figured I could do a bit better with the filing then I did. After a couple strokes I fired about 300 rounds, and except for 3 exceptions no noticeable tool marks on the cartridges and no functionality issues

Heres what my average spent cartridges looked like:

I'm very pleased with the results! The chamber face doesn't appear to be getting as dirty as fast. And I feel pretty good knowing I didn't have to send it back

Once again, thanks Bullseye for giving me the knowledge to fix it

Post by **Bullseye** » Fri Nov 23, 2007 4:59 am

Good deal!

R,
Bullseye