Brass issue

dryfire

dryfire

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Full Member
Minuteman
Mar 2, 2017
81
12
WV
#1
I'm getting a ring imprinted on my brass that only goes half way around the case. This happens after firing. It is not present when it first comes out of the FL sizing die. It appears after firing leading me to think that the rifle chamber may be causing the blemish to appear.
Image of sized case before firing, normal appearance:
66676b70afade1f651d50db40c1bedeb.jpg

Images after firing, note the rings above the cartridge base:
c9f172ef3e311967ee111e32ac9268a2.jpg

61dc91fa62cfdbc2f334b37dd0d14dcc.jpg

After 2-3 cycles of reloading, the ring works its way completely around the case. On the forth reloading I found one to be split in this location.
Any ideas as to what could be going on?




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#5
Happens with Lapua, Winchester, and Federal brand cases. It's 223 Rem brass necked up to 6x45. Primers start showing pressure signs at least 2 grains below listed max loads. Anything much higher than starting charge weights begin to flatten primers. It's even pierced a few primers at 1.5 gr less than Hodgdon max data.
I haven't shot them over a chronograph yet but I will when I shoot with my brother this week.
The rifle is a Rem 700 SA, .300" recoil lug, Bartlein 6mm 8 twist Rem varmint contour barrel, chambered in 6x45. My dies are Forster BR die set.
The above rounds were part of a 23.0 gr Benchmark powder, Berger 87 vld-h, CCI 400, Win case. COAL 2.495"




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#7
Once fired brass looks like this with 3 brands of brass, 3 types of powder, and 95 TMKs, 87 Berger VLD-Hs, and 95 VLD-Hs. Again, it does this with recommended starting load volumes and primers show pressure in short order.



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#9
Are you putting bullets into the lands? Many things can cause overpressure, but jamming the bullet into the lands when you close the bolt because either the chamber was cut too tight on headspace or the throat is too short.
When you size the brass, how far are you bumping the shoulder back?
Tell us a little about the 6x45 setup. Who did the chamber and was it cut with your bolt? Running suppressed?
 
#10
Case head looks good, no ejector marks, etc. Always at least 0.015" off lands. 0.015-0.80" off lands. 0.002" bump on the shoulder. Not suppressed. Reamer was 0.050 free bore



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#12
Any issues with extraction? Do they look like this before you put them in the box? I'd like to see a case or two cut in half. Until we know if it's thin brass or just plastic box edges polishing the case it's all just speculation.

I don't like hearing you're going over pressure early. Something isn't adding up when I look at the resize specs. Any chance you have a tight bore? How are you measuring your headspace setback?
 
#13
Sticky extraction on occasion but not always. Don't look like this before loading mag. Come out of the chamber like this after first firing. I think the bore may be tight. Unsized virgin brass without a bullet chambers with resistance, bolt close feels tight. The early pressure signs with the primers bothers me. Accuracy is really disappointing too. Struggles to average 1/2 MOA. This whole project has been a shit sandwich. Coming up on 300 rounds down this barrel. This action was once threaded to a 223 Rem in varmint factory contour barrel. It was a hammer, 10 shot 1/4 MOA groups. With this 6x45 I'm in deep as far as $ goes but I'm about ready to cut my losses. Frustrated.
24f212b834866dd69b5257596899cd6b.jpg

It's wearing a different optic now.


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Last edited:
#14
I use a machined brass sleeve slid over a fired case shoulder. Measure that length, then measure a sized case with the same sleeve. It measures .002" shorter after FL sizing.




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#16
dryfire said:
No. I shoot at home on my farm. I walk 30 yards to my bench.




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Click to expand...

then unless you have some super weird shit going on, you have pressure to the point of almost separating or a flaw in your chamber. cut a couple of the cases length wise and see if the brass is thin. if it is, I would immediately find a second way to check your headspace and back that load down significantly.
 
#17
FatBoy said:
then unless you have some super weird shit going on, you have pressure to the point of almost separating or a flaw in your chamber. cut a couple of the cases length wise and see if the brass is thin. if it is, I would immediately find a second way to check your headspace and back that load down significantly.
Click to expand...

Ok, thanks. I'll try to cut a case open to see if the inside has any deformities too. I'm already at the starting charge weight per Hodgdon load data. (23.0 gr). The pressure issue has me worried the most.


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#18
you have an odd issue. tight chambering on new brass doesn't indicate excess headspace and if you are at starting loads you shouldn't be seeing pressure. very light loads can cause pressure in the case but if you're at a starting load you should be ok.
 
#19
FatBoy said:
then unless you have some super weird shit going on, you have pressure to the point of almost separating or a flaw in your chamber. cut a couple of the cases length wise and see if the brass is thin. if it is, I would immediately find a second way to check your headspace and back that load down significantly.
Click to expand...

Agreed.

I'm just guessing here but 99% sure there's either a headspace measurement error or a shoulder setback measurement error.

There should be no way that a well cut chamber, with proper headspace, and shoulder setback of .002 is going to leave brass looking that way. I would assume nothing and measure everything again and make damned sure that the measurements are being taken correctly and any associated math doesn't have mistakes in it.

 
#22
308pirate said:
Agreed.

I'm just guessing here but 99% sure there's either a headspace measurement error or a shoulder setback measurement error.

There should be no way that a well cut chamber, with proper headspace, and shoulder setback of .002 is going to leave brass looking that way. I would assume nothing and measure everything again and make damned sure that the measurements are being taken correctly and any associated math doesn't have mistakes in it.
Click to expand...

Oversizing brass and causing excess headspace also causes pressure problems. I think we are looking at one compounding problem that all has to do with the reason they are separating. How hard is it to measure the shoulder on a 6x45, I know there is hardly any shoulder left on a 7mmTC.

I would have never touched that 1/4 moa {LOL} factory rifle.
 
#23
My guess, the resizing die is set up a tad too short, causing the case to stretch lengthwise as everything expands under pressure as it's fired.

The shiny ring is where the case wall is thinnest, just above the case web, and results as the case wall rubs the inside of the chamber as it stretches. Several resizings and firings later, the case wall fails due to fatigue, resulting in a case head separation.

Adjust the die longer (upward) in small increments. The ring, and the problem, should be reduced and eliminated as the resizing process gets slightly reduced.

The die is adjusted properly when the resized case causes minor bolt drag on closure, demonstrating that there is no excess case length clearance between the case and chamber shoulder.

This is a classic issue.

Greg.
 
#25
Greg's process sounds like mine. I would get a measurement between a virgin piece of brass and a fired piece to see where you're starting. I take a final HS measurement AFTER I set me die up. my process:

clear the rifle
clean the chamber and throat
pull the firing pin assemble
chamber a couple pieces of fired brass and get a feel for them
set the FL die WAY long
lube one case
size said case
chamber it
screw die down 1/16 turn
resize
repeat until the bolt every so slightly drags at just the bottom of pushing the handle down
adjust down 1/32 more and tighten lock ring slightly
unscrew die and then run it down to the locking ring to seat it
lube and size 2 or 3 more cases, the handle may drag a tiny bit due to the ejector and extractor, but you'll be able to feel the difference between brass crush and spring. if you can't, pull the ejector out.

Then, take a measurement against a freshly sized piece of brass and a fired case and record it. generally, I find this gives me about .002" setback with no ejector or .003" with ejector in.

If you don't want to go through this, get a Lee Collet die for $20 and neck size only a dozen or so. if they shoot and you don't have a ring, it's HS.
 
#26
FatBoy said:
Greg's process sounds like mine. I would get a measurement between a virgin piece of brass and a fired piece to see where you're starting. I take a final HS measurement AFTER I set me die up. my process:

clear the rifle
clean the chamber and throat
pull the firing pin assemble
chamber a couple pieces of fired brass and get a feel for them
set the FL die WAY long
lube one case
size said case
chamber it
screw die down 1/16 turn
resize
repeat until the bolt every so slightly drags at just the bottom of pushing the handle down
adjust down 1/32 more and tighten lock ring slightly
unscrew die and then run it down to the locking ring to seat it
lube and size 2 or 3 more cases, the handle may drag a tiny bit due to the ejector and extractor, but you'll be able to feel the difference between brass crush and spring. if you can't, pull the ejector out.

Then, take a measurement against a freshly sized piece of brass and a fired case and record it. generally, I find this gives me about .002" setback with no ejector or .003" with ejector in.

If you don't want to go through this, get a Lee Collet die for $20 and neck size only a dozen or so. if they shoot and you don't have a ring, it's HS.
Click to expand...

Thank you. I appreciate your detailed process.



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#27
wasn't trying to be a smartass. I had an issues with some 47L brass and a Hornadays HS gauge so I just use the bolt now.
 
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