Are pressure rings close to the ejector ring normal? At what point does it indicate too much pressure.
pressure rings...is it normal?
- Thread starter turbohardtop
- Start date
Re: pressure rings...is it normal?
What are you shooting? Rifle or pistol? Is it an actual ring you can feel with your fingernail or it just looks shiny?
What are you shooting? Rifle or pistol? Is it an actual ring you can feel with your fingernail or it just looks shiny?
Re: pressure rings...is it normal?
Please elaborate further as im not sure what your talking about.
Please elaborate further as im not sure what your talking about.
Re: pressure rings...is it normal?
sorry for lack of details. I am developing a load for a 308 rifle. Going from a 42.0 - 45.0 grains of varget I can see a ring close to the bottom of the case. If I look closely at the base close to the ejector ring, I can see that this ring going from just visible to almost bumpy with feel as I go up on powder. This is with 168grain SMK.
sorry for lack of details. I am developing a load for a 308 rifle. Going from a 42.0 - 45.0 grains of varget I can see a ring close to the bottom of the case. If I look closely at the base close to the ejector ring, I can see that this ring going from just visible to almost bumpy with feel as I go up on powder. This is with 168grain SMK.
Re: pressure rings...is it normal?
About 1/8" above the bevel?
I would hazard a guess that the ring is where the sizing die stops sizing.
Normal.
Cheers,
Doc
About 1/8" above the bevel?
I would hazard a guess that the ring is where the sizing die stops sizing.
Normal.
Cheers,
Doc
Re: pressure rings...is it normal?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbohardtop</div><div class="ubbcode-body">sorry for lack of details. I am developing a load for a 308 rifle. Going from a 42.0 - 45.0 grains of varget I can see a ring close to the bottom of the case. If I look closely at the base close to the ejector ring, I can see that this ring going from just visible to almost bumpy with feel as I go up on powder. </div></div>
When comparing a brand new case with a case that has been fired, you will find an outdentation a couple of mm above the cut for the extractor. This outdentation is completely normal. When the pressure builds upon ignition, the case is forced out to the chamber dimensions. The case base has enough material to hold its shape, but the thinner wall just above the base does not. This is what you see with the outdentation.
On the other hand, if you see a ring of bright metal about 4mm above the cut that is indicative of oversizing and impending case failure. This ring does not protray an outdentation, just a change in grain structure. You can check for this with the famous paperclip trick. Take a paper clip and file/sand the tip rather sharp. Then bend it at 90 degrees but only about 1-2mm long. Stick the bent feeler into a case and feel down near the bright ring. If the wall has any change in thickness, the cae is basically toast and will rupture shortly.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbohardtop</div><div class="ubbcode-body">sorry for lack of details. I am developing a load for a 308 rifle. Going from a 42.0 - 45.0 grains of varget I can see a ring close to the bottom of the case. If I look closely at the base close to the ejector ring, I can see that this ring going from just visible to almost bumpy with feel as I go up on powder. </div></div>
When comparing a brand new case with a case that has been fired, you will find an outdentation a couple of mm above the cut for the extractor. This outdentation is completely normal. When the pressure builds upon ignition, the case is forced out to the chamber dimensions. The case base has enough material to hold its shape, but the thinner wall just above the base does not. This is what you see with the outdentation.
On the other hand, if you see a ring of bright metal about 4mm above the cut that is indicative of oversizing and impending case failure. This ring does not protray an outdentation, just a change in grain structure. You can check for this with the famous paperclip trick. Take a paper clip and file/sand the tip rather sharp. Then bend it at 90 degrees but only about 1-2mm long. Stick the bent feeler into a case and feel down near the bright ring. If the wall has any change in thickness, the cae is basically toast and will rupture shortly.
Re: pressure rings...is it normal?
In other words, yeah, it's normal. You will also see it on factory ammo. A small base sizer die restores cases to factory diameter but normal FL dies don't, not do they need to.
And it's an 'extractor' groove, not 'ejector'; think that may have been part of the confusion.
In other words, yeah, it's normal. You will also see it on factory ammo. A small base sizer die restores cases to factory diameter but normal FL dies don't, not do they need to.
And it's an 'extractor' groove, not 'ejector'; think that may have been part of the confusion.
