Marks/lines on case near extractor grove

[JDR41]

I am going to reload some .308 Win, and just finished re-sizing/trimming/wet tumbling, and noticed these lines/marks on the rear of the case about 1/8" forward of the extractor groove.

See pictures:









They look similar to what I've heard as a pressure ring. This was all factory ammo either Federal Premium Gold Medal Match or HSM of various grain bullets.

I'm thinking I may have caused this during my re-sizing as I didn't wait for the spray lube to dry and also may have been heavy on the spray. I'm using a home brew of 10 to 1 ISOPROPYL ALCOHOL (10 PARTS) TO LANOLIN OIL (1 PART) for lube and as I mentioned may have been excessive with the amount and didn't wait for the alcohol to dry.


Please let me know if I should be concerned with these cases or not.

Thanks in advance.

[dung8604]

Anytime I see this in my brass I throw it out. Looks like impending Case head separation to me.

Sent from my Nexus 4 using Tapatalk

[OpenSightsOnly]

Gas gun or bolt gun?

If you neck size then that's just where the sizing die stopped

If you FL size for a gas gun, how many times have you reloaded the brass? I get that same ring from FL sized brass of 223 and 30-06 for gas guns. I use the bent paper clip to check if the case web is thinning-out due to FL sizing. I see this more from brass fired out of an M1 Garand plus you can see that ring and feel the case bulge, sign that the brass is thinning-out.

[Multra]

That's very common and f4tweet is probably right. If it was case head separation it would be a bright whitish line. As long as the cases aren't bulging out right there it isn't pressure. If you are scared to use the brass send it to me, I will make sure it is properly disposed of

[damndave]

It looks like where the sizing die stopped just above the web in the case.

Brass is perfectly fine.

[JDR41]

The gun is a new Savage Bolt Gun with their Target Action and I'm using a Hornady Custom Grade Full Length Die set.

OpenSightsOnly, can you explain your coment, bent paper clip to check if the case web is thinning-out due to FL sizing. Not quite sure want that means as I have never heard of it.

[edwardm]

Every modern 30-06 bolt action rifle I've owned (lots) does this. I think the manufacturers oversize the back end of the chamber, but I don't know why. I've even had it happen on 2 different M1A's of Springfield origin and I've noticed it to a lesser extent on bolt-action .223 rifles of recently manufacture.

The only 30-06 rifle I haven't seen this on is a 1903 Springfield built sometime in 1918/1919.

The paperclip trick is easy. Take a paperclip. Straighten it out, and use a pair of pliers to bend one end over into an "L", where the short leg of the "L" is short enough to fit in the case mouth. Insert the paperclip, and slowly drag it up against the inside of the casing where that bulge is.

What you want to feel is nothing - the area of the bulge should be smooth like the rest of the interior. If you feel a snag, that's an internal crack and the case head is about to come apart on the next firing. Thing is, that bulge is a little too high on the brass to be the location for a case head separation. Not saying it cannot happen, just saying it's hardly ever seen in that particular spot.

To get a visual of what's going on in the chamber relative to chamber depth vs diameter as the breech vs. bolt location, take a factory new round, pull the bullet and powder (to be safe), reseat the bullet, smoke the whole round with a candle, and ease it into the chamber. Close the bolt, open the bolt, and remove the round. You'll see where the chamber doesn't touch one part of the casing very much. If smoke is too delicate for your needs, sharpie will work too. If you use sharpie, make a mark at one part of the casehead and let that always be your "up". Rechamber the round several times with that "up" always in the 12 o'clock position. Examine the areas where sharpie is gone. It'll tell, visually, the story I'm trying to tell in words.