Case neck dents, not from resizing oil...

Here is what is happening, I am just starting reloading for my savage. My recipe varies so far in total length (TL) and Charge and it goes something like this.

Bullet: A-Max 168gr
Powder: IMR4064
Primer: Winchester WLR

168gr.
TL 2.75"
Charge: 10 count of 42, 42.5, 43, 43.5

168gr.
TL 2.8"
Charge: 10 count of 42, 42.5, 43, 43.5

168gr.
TL 2.85
Charge: 10 count of 42, 42.5, 43, 43.5

About a week after testing these loads I started cleaning the brass when I noticed this: https://7w3qfa.bay.livefilestore.com...738.JPG?psid=1
What is causing this?

I saw a thread on something like this a while back that Sharpshooter replied to.
If I remember correctly it had something to do with the charge weight being too low causing the brass not to expand in the chamber properly. The back pressure from the gas as it pushes the bullets down the barrel then slips past the case necks and dents/collapses the shoulder as shown in your pic.

I forgot to mention that it only happened on the 2.8" and 2.85" total length loads. All the 2.75" loads didn't have these dents. Also, is it safe to reload these. If I reload these it would be the 3rd time it will be shot.

It looks to me like something was in your chamber and the brass formed to it. I have had powder in my chamber before and you could see the shape of the individual kernals of powder in the fired brass.

I bet you shot all the same length cartridges at the same time. If so, then what ever it was got in the chamber then you shot the 2.8" and 2.85 inch groups.

Have you shot any rounds after those lengths, and did they imprint also? Have you cleaned your chamber since then? Did you get anything out of it that appeared to be shaped like the dents?

It could be low pressure loads, but the dents look too uniform to me.

My vote is something was in the chamber shoulder area causing the dents, clean the chamber and see if it removes the problem.

Shoot these cases again and the dents and wrinkles will be gone. I had the opposite problem once and had to send the rifle back to the factory, the chamber had a chip in the shoulder area and my fired cases had a pimple in the shoulder.

Dents do look too uniform. I assume you did all the necessary case calibration measurements after resizing? Did you carefully gauge CBTO for the rifle's chamber and for the bullet used--since you mentioned it happened only to the longer loads they may have engaged the lands and then pushed the bullet back? I'm no expert and just started reloading--but if it were me I'd toss the brass. Also, you don't mention caliber--I'm assuming from the pics and loads 308/30 cal (Lyman book mentions 4064 as launching lighter <=150 grain bullets)?

I still think it's a problem with the brass not expanding correctly. I have a big AR that does it and have been told its something in the timing. It seems with the AR that the bolt is moving rearward too quickly but I haven't had time to put it in the shop or ask the manufacturer. It shoots very well and no other failures just mangled brass with a dent in the shoulder.

Hi. I reload 29 calibers and have been doing so for over 40 years. I work on a rifle/load until it will shoot < .5". I have purchased 4 Axis rifles last year (and will buy another tomorrow!!).
I only mention this because, as mentioned above, these dents look WAY too consistent to be anything other than debris in the chamber. I'd take it to a gunsmith with a borescope, if nothing other than to eliminate this aspect.
One of the cases almost looks like a 'gas trail' from the case mouth to the 'dent'... strange indeed, but interesting!!!

ron

Ben Archer:
Please take a few minutes to search for instructions on how to post photos so that they show up in your posts. It's on the forum, it's not hard to find, and the actual posting is easy.
Please have some consideration for others and don't make them have to click to get to your photos when it is just as easy to have the pictures there for them to see.
Yes, this is one of my pet peeves. I feel that, as a matter of courtesy, If you want people to look at your pictures, make them visible.
Thank you.

P.s., ...And that goes double for the rest of you standing over there in the corner giggling because Ben got in trouble and you didn't. Stand by, you have been warned!

Sorry for forgetting the caliber, it is .308, also the rifle is a Savage 10. The far right case in the picture is one that I have re-sized. I took a look at some of the Brazilian ammo that Turner's had on sale and there was the same dents on them.

Sorry about the image link, but I didn't think you would appreciate a gigantic picture on the thread.

With the dents all looking almost the same i agree with trash in the chamber. You need to have a really good look at the shoulder area of the chamber because you could leave an impression in the chamber of whatever the trash was. I know because i have the imprint of a single grain of varget in a recoil lug and no folks it didn't not crush the powder grain just made an imprint in the steel.

I'm thinking if there were trash or an imperfection that large at the shoulder it would be very difficult to chamber a round unless the headspace was excessive.

Update: Last weekend I went out shooting with some friends and as it turned out, it was debris in the chamber that was causing the dents. Now my question to you guys is, would it be safe to reload these dented cases?

Yes sir. 50-60k psi has a way of fixin it right up

I agree. Shoot em.

Woot!!! Thanks for the advice fellas.