wondering what to look for, for over pressure signs.
Specificaly in a 6.8spc AR but any pics would be helpful!
C
Specificaly in a 6.8spc AR but any pics would be helpful!
C
- Thread starter fastford
- Start date
Re: anybody have pressure signs pictures?
This was shot in my AR15 with a high pressure load: 18 gr Blue Dot 33 gr Vmax, 4200 fps 26" barrel.
You can see raised areas where the bolt face did not push back. These are extractor mark and the ejector.
There is also a raised crater on the primer.
There is also a stretch mark in front of the web.
This was shot in my AR15 with a high pressure load: 18 gr Blue Dot 33 gr Vmax, 4200 fps 26" barrel.
You can see raised areas where the bolt face did not push back. These are extractor mark and the ejector.
There is also a raised crater on the primer.
There is also a stretch mark in front of the web.
Re: anybody have pressure signs pictures?
Funny thing is i get craters like that on my cases even when i fire factory loads... Im guessing this is because i have a remington 700
Also, Clark in that picture, that "belt" around the base of the case is also a sign of too high pressure... looks like case-head seperation was around the corner for that case... or is that some sort of belted case?
Funny thing is i get craters like that on my cases even when i fire factory loads... Im guessing this is because i have a remington 700
Also, Clark in that picture, that "belt" around the base of the case is also a sign of too high pressure... looks like case-head seperation was around the corner for that case... or is that some sort of belted case?
Re: anybody have pressure signs pictures?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">..
Also, Clark in that picture, that "belt" around the base of the case is also a sign of too high pressure... looks like case-head seperation was around the corner for that case... or is that some sort of belted case? </div></div>
I call it stretch marks.
A friend of mine got gas and brass in the eye from his Rem700 223 with a low pressure reload, because the case failed in front of the web. One theory is that the brass had been fired in a machine gun that stretched it.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">..
Also, Clark in that picture, that "belt" around the base of the case is also a sign of too high pressure... looks like case-head seperation was around the corner for that case... or is that some sort of belted case? </div></div>
I call it stretch marks.
A friend of mine got gas and brass in the eye from his Rem700 223 with a low pressure reload, because the case failed in front of the web. One theory is that the brass had been fired in a machine gun that stretched it.
Re: anybody have pressure signs pictures?
Ahhh damn that sux! Can your friend see out of that eye?
Ahhh damn that sux! Can your friend see out of that eye?
Re: anybody have pressure signs pictures?
My friend was one eyed for a few days, now he has a complete recovery, and is shooting the same rifle again, but only with Winchester brass he buys new himself and scrutinizes.
My friend was one eyed for a few days, now he has a complete recovery, and is shooting the same rifle again, but only with Winchester brass he buys new himself and scrutinizes.
Re: anybody have pressure signs pictures?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">Funny thing is i get craters like that on my cases even when i fire factory loads... Im guessing this is because i have a remington 700</div></div>
Ditto. Ive always thought that was funny. Every one of my reloads too, from the low end of the loading tables on up. No other signs though so i keep on shootin! LOL.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">Funny thing is i get craters like that on my cases even when i fire factory loads... Im guessing this is because i have a remington 700</div></div>
Ditto. Ive always thought that was funny. Every one of my reloads too, from the low end of the loading tables on up. No other signs though so i keep on shootin! LOL.
Re: anybody have pressure signs pictures?
High pressure loads cause plastic deformation as we see in the above pics. I would guess the above loads saw 70 to 80,000 PSI.
Case heads on 30.06 are gone at 115,000 and you don't want to be holding it when it happens.
Hope the guy that had the failure is now wearing shooting glasses.
Such head failures can also occur with normal loads if the case has been in a fire and gets stress relieved thus making the head soft. Be careful of cases picked up in the fields as if the field has been burned etc it can be bad day.
On the older 5.56 cases before firing new ammo one should also check to make sure the neck/shoulder is blue AND NOT THE HEAD. If head is blue the case head will fail, blow mag out of rifle and bow upper receiver out and the operator will sheeeeet! ! ! !
What happened was the cases would go throught the stress relieve line upside down. On the new stuff loaded on SCAMP lines they are induction stress relieved.
High pressure loads cause plastic deformation as we see in the above pics. I would guess the above loads saw 70 to 80,000 PSI.
Case heads on 30.06 are gone at 115,000 and you don't want to be holding it when it happens.
Hope the guy that had the failure is now wearing shooting glasses.
Such head failures can also occur with normal loads if the case has been in a fire and gets stress relieved thus making the head soft. Be careful of cases picked up in the fields as if the field has been burned etc it can be bad day.
On the older 5.56 cases before firing new ammo one should also check to make sure the neck/shoulder is blue AND NOT THE HEAD. If head is blue the case head will fail, blow mag out of rifle and bow upper receiver out and the operator will sheeeeet! ! ! !
What happened was the cases would go throught the stress relieve line upside down. On the new stuff loaded on SCAMP lines they are induction stress relieved.
Re: anybody have pressure signs pictures?
I have split the cylinders on 4 revolvers, and 2 broke the top strap in the rear and bent it upwards. I have never broken off the top strap in the front and the rear as shown in the above link.
I have blown case heads in semi auto pistols that blows the extractor in half and exits at bullet speed. It also blows the mag follower, ammo, mag spring and mag bottom plate out the bottom. The real problem for the shooter is the brass and gas that comes out the back of the slide on the ejector slot. When that hit the shooter and he bleeds, it is called "major face", for guys who tried to make major with 9mm.
I have slit the chamber on a couple CZ52 pistols. The extractor can exit stage right at lethal velocities.
When the case head fails in a modern strong rifle, the extractor or extractor pieces can come to where the shooter's face would be. I did this, but I was beneath the rifle [anticipating this might happen], so I was not hit.
I have split the cylinders on 4 revolvers, and 2 broke the top strap in the rear and bent it upwards. I have never broken off the top strap in the front and the rear as shown in the above link.
I have blown case heads in semi auto pistols that blows the extractor in half and exits at bullet speed. It also blows the mag follower, ammo, mag spring and mag bottom plate out the bottom. The real problem for the shooter is the brass and gas that comes out the back of the slide on the ejector slot. When that hit the shooter and he bleeds, it is called "major face", for guys who tried to make major with 9mm.
I have slit the chamber on a couple CZ52 pistols. The extractor can exit stage right at lethal velocities.
When the case head fails in a modern strong rifle, the extractor or extractor pieces can come to where the shooter's face would be. I did this, but I was beneath the rifle [anticipating this might happen], so I was not hit.
Re: anybody have pressure signs pictures?
In most cases, by the time you can see it you are already way over. All the cases shown were well over.
Load for accuracy, forget speed. If you MUST load for speed then use every tool you can get including a chronograph. You then get the additional "tool" of looking for you ratio of FPS to weight drop then peak. You load back from this point. Of course, you don't assume every gun will show the same thing and keep pushing.
That's the only time I find a Chonograph to be a lot of use.
In most cases, by the time you can see it you are already way over. All the cases shown were well over.
Load for accuracy, forget speed. If you MUST load for speed then use every tool you can get including a chronograph. You then get the additional "tool" of looking for you ratio of FPS to weight drop then peak. You load back from this point. Of course, you don't assume every gun will show the same thing and keep pushing.
That's the only time I find a Chonograph to be a lot of use.
Re: anybody have pressure signs pictures?
It would be nice to have a sticky in here where people can post examples of different types of pressure signs. Its a pretty common question. It would be nice to be able to easily reference a single post when the question is asked.
It would be nice to have a sticky in here where people can post examples of different types of pressure signs. Its a pretty common question. It would be nice to be able to easily reference a single post when the question is asked.
