Got brass troubles. Cause ? Video posted

[RegionRat]

Sorry for late reply. Post 72 pictures clearly show a difference in interior polish at the separation area . Did anyone else see that .

I did and commented on it but I don't know if there's any significance to it?

Without running a profilometer there, it is hard to say from just the photos.
The design does have a transition there where the thickness profile comes up from the head with a taper and then blends to a thinner profile right at that place.

Even then, without knowing the hardness and residual stress, we wouldn't know if those are rejects or normal.

 

[DShortt]

Without running a profilometer there, it is hard to say from just the photos.
The design does have a transition there where the thickness profile comes up from the head with a taper and then blends to a thinner profile right at that place.

Even then, without knowing the hardness and residual stress, we wouldn't know if those are rejects or normal.

I freely admit I've not segmented brass cases ever so I've no idea what the interior finish typically looks like but I do have a Teslong bore scope and some new Starline brass. .223 Remington to be exact. I'll post some photos soon. This should be interesting.

 

[DLT]

Sorry for late reply. Post 72 pictures clearly show a difference in interior polish at the separation area . Did anyone else see that .
I skimmed the 10 pages so sorry if its already been discussed.
Gary

There is a difference in the finish your correct. There is also a divot/low spot right there also.

 

[DLT]

I freely admit I've not segmented brass cases ever so I've no idea what the interior finish typically looks like but I do have a Teslong bore scope and some new Starline brass. .223 Remington to be exact. I'll post some photos soon. This should be interesting.

I did the same experiment with 2 new starline cases, I couldn’t see squat with the bore scope. I can however pick up the slightest irregularity inside the body when shining a flashlight through the case mouth but it’s hard to pick up. I split those cases and it was there. I have also fired 8-10 of a new batch of starline brass and can feel the line on the outside of the brass. I really feel it’s mainly the brass fault. LC brass is holding up better BUT I am not running that hot of a load. I have decided against the hot load that was shooting pretty good.

 

[RegionRat]

There is a difference in the finish your correct. There is also a divot/low spot right there also.

I did the same experiment with 2 new starline cases, I couldn’t see squat with the bore scope. I can however pick up the slightest irregularity inside the body when shining a flashlight through the case mouth but it’s hard to pick up. I split those cases and it was there. I have also fired 8-10 of a new batch of starline brass and can feel the line on the outside of the brass. I really feel it’s mainly the brass fault. LC brass is holding up better BUT I am not running that hot of a load. I have decided against the hot load that was shooting pretty good.

An earlier die punch used to deep draw and start the head has a cone shaped taper to a straight diameter, then a later die starts the body taper. So... In that place, there is always a radius blend or facet transition from the taper thickness to the thin wall body that is very difficult to judge visually because it is bent after that deep draw.

You either section or run the profiles to know for sure. We had custom probe tips to plunge down through the necks and get into the body so we could check non-destructively. The outside was easy.

Not every lab had the capability, so many places just section.

 

[Jeff Porter]

I have seen this bad annealing of Starline brass rearing its head on more than one forum lately. All from the 2021 lot it seems.

 

[RegionRat]

I have been watching too, but so far there is no conclusion either way which still leaves the possibility of issues caused unintentionally by users.