False Positive Pressure Signs

[orkan]

There seems to be a plague of bad bolt faces slipping out to the world lately. I've had no fewer than 5 conversations about this in the past 2 weeks alone. So I figured a public service announcement was necessary. Some of you may remember an article I wrote many years ago describing how to read pressure signs. I make mention of this issue in that article. Here it is for those that haven't read it:

Understanding Pressure :: Primal Rights, Inc

Reading pressure is a required skill that all shooters must have. Whether you are shooting factory ammunition or your own handloads, you absolutely must be able to detect and interpret pressure signs on your fired brass.

www.primalrights.com

I just received a new rifle that had the false positive issue, so I wanted to document it here. Folks, this is why it's so important to use a smith that will catch issues like this before they get out to you. These days, Taylor Stratton at Stratton Custom Rifles in Delta Colorado does my work... and one of the main reasons I chose him is that he will properly evaluate and fix each action he builds on as a matter of course. Many smiths rely on the action manufacturers to catch issues, and they simply do not.

The issue at hand is this:

My brand new rifle, was demolishing my cases... making it appear as I was running a massively over-pressure load. The action I'm using is a brand new Lone Peak Fuzion. The action did not have the ignition properly timed, nor did any of the other burrs or issues get fixed. (was not built at SCR) I have vast experience with 22 creedmoor, so I knew that 40gr of H4350 behind a 70gr berger was not a hot load, and was not over pressure. This is further evidenced by the fact that the primer is not cratered, not flat, and there are no other defining signs of pressure beyond the massive ejector wipe.

I've run into this issue several times before, and while it is sad that a top level action such as a Lone Peak Fuzion exhibit this problem... it's very obvious what is going on. When the hole for the ejector was drilled, the bolt face was not cleaned up afterward, leaving a massive burr around the ejector hole. The proper fix is to fully indicate the bolt in true, and then run a cleanup cut on the bolt face. However, this needs to be done before the barrel is installed, as it will alter headspace. So, in order to fix it... I use a special cylindrical stone, and twist it across the surface by hand.

The stone I use to fix the issue.

Here you'll notice the burr is removed, as evidenced by the shiny ring around the ejector pin hole. Not an easy area to work in manually.

I've seen this on many actions in my career... and it's a shame, because all would be needed is for the final bolt face cut to be performed AFTER the hole is drilled for the ejector... then a quick twist in the ejector pin hole with a deburr tool or 45° abrasive point to handle the ID burr. The most unpleasant part about this is the fact that a great many shooters do not have the experience to tell false positive pressure, from actual pressure. So they end up chasing their tail in frustration for a long while before reaching out to me for help. Then once this problem is discovered, it's not trivial for someone without much experience to fix this on their own.

Hopefully this will help any of you that might encounter this in the future.

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[TennJed]

Thank you!

 

[billcaldwell]

Thank you for posting this. I would have been chasing my tail! I'm always amazed at the knowledge on this forum!

 

[8andbait]

Funny you mention this, I recently got a new build from a well known smith that had the exact issue, (wasn't a lone peak).
The rifle was "test fired" before delivery so I don't know how no one caught it.
I fired the first shot and noticed the swipe from a mild load.
I was able to correct it with a small exacto knife blade after removing the ejector.
No harm done but for what people are charging I expect a little more.

 

[BillLarson]

Thank you VERY much for a very well written and photographed article....
How many of us,having a sticky bolt lift first inspect primers after firing..???...
This article brings attention to the fact that in our age of CNC equipment is not always perfect,small little overlooked,hard to see manufacturing errors and oversite get through the inspection dept.....
Question:after you deburred boldface did you have to pull barrel a reaching to close up headspace...???

 

[orkan]

after you deburred boldface did you have to pull barrel a reaching to close up headspace...???

I generally instruct my smiths to run my chambers a little long anyway. I'm an advocate of proper fire forming for the first firing, but in this instance, no, because apparently the smith shot this chamber directly to reamer print, and because the burr was in such a small area, it's likely the headspace I was seeing after firing stayed constant because the burr was pounded into the brass, not really changing anything. So, 5x fired case was only .003 longer than virgin Alpha OCD.

So to directly answer you question, no issue with headspace was created from removing the burr. This is especially true considering the 22 creed has no SAAMI spec anyway.

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[JTB]

Another case in point. I also have a premium action that was demonstrating false pressures with heavy bolt lift. After chasing my tail for some time I discovered that the bolt face had not been cut exactly perpendicular to the bolt itself. I chucked it into my lathe and squared the bolt face and it opened as smooth as glass after that. It was distorting the cases when fired against the un-squared bolt face resulting a perceived heavy bolt as it rotated open against the fired-formed and, now, un-square case head. Required a slight chambering adjustment but until then I had never thought to check this. The cases that had been distorted were never the same, even after a second firing against the squared bolt face; ended up tossing them. Lesson learned

 

[orkan]

The cases that had been distorted were never the same, even after a second firing against the squared bolt face; ended up tossing them. Lesson learned

This is why the video I made about beating up your brass is so important to understand. Once you experience plastic deformation of a portion of the case that isn't designed to have elastic deformation... it will never go back. The very definition of plastic deformation. If you experience heavy bolt lift... that case will NEVER be what it once was.

These bolt face issues are the cause of so much frustration among shooters. Thus the need for this PSA.

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[FrogFire7]

Thanks Orkan. I came across your first article probably 7 or so years ago when I was fairly new to reloading, and to this day I find it to be probably the most helpful single piece of information about reloading that I've come across, maybe other than my initial reading of the reloading manual. I use that information every single time I start a new load, and reference it every so often just to make sure I'm not missing anything.

The new post you just made is definitely interesting... I only have one custom action (Bighorn TL-3), and haven't had issues with that, but have seen some ejector swipe on several factory actions that had me puzzled at the time. This is definitely good info! I appreciate your time and input here

 

[Scott E Ames]

There seems to be a plague of bad bolt faces slipping out to the world lately. I've had no fewer than 5 conversations about this in the past 2 weeks alone. So I figured a public service announcement was necessary. Some of you may remember an article I wrote many years ago describing how to read pressure signs. I make mention of this issue in that article. Here it is for those that haven't read it:

Understanding Pressure :: Primal Rights, Inc

Reading pressure is a required skill that all shooters must have. Whether you are shooting factory ammunition or your own handloads, you absolutely must be able to detect and interpret pressure signs on your fired brass.

www.primalrights.com

I just received a new rifle that had the false positive issue, so I wanted to document it here. Folks, this is why it's so important to use a smith that will catch issues like this before they get out to you. These days, Taylor Stratton at Stratton Custom Rifles in Delta Colorado does my work... and one of the main reasons I chose him is that he will properly evaluate and fix each action he builds on as a matter of course. Many smiths rely on the action manufacturers to catch issues, and they simply do not.

The issue at hand is this:

My brand new rifle, was demolishing my cases... making it appear as I was running a massively over-pressure load. The action I'm using is a brand new Lone Peak Fuzion. The action did not have the ignition properly timed, nor did any of the other burrs or issues get fixed. (was not built at SCR) I have vast experience with 22 creedmoor, so I knew that 40gr of H4350 behind a 70gr berger was not a hot load, and was not over pressure. This is further evidenced by the fact that the primer is not cratered, not flat, and there are no other defining signs of pressure beyond the massive ejector wipe.

I've run into this issue several times before, and while it is sad that a top level action such as a Lone Peak Fuzion exhibit this problem... it's very obvious what is going on. When the hole for the ejector was drilled, the bolt face was not cleaned up afterward, leaving a massive burr around the ejector hole. The proper fix is to fully indicate the bolt in true, and then run a cleanup cut on the bolt face. However, this needs to be done before the barrel is installed, as it will alter headspace. So, in order to fix it... I use a special cylindrical stone, and twist it across the surface by hand.

The stone I use to fix the issue.

Here you'll notice the burr is removed, as evidenced by the shiny ring around the ejector pin hole. Not an easy area to work in manually.

I've seen this on many actions in my career... and it's a shame, because all would be needed is for the final bolt face cut to be performed AFTER the hole is drilled for the ejector... then a quick twist in the ejector pin hole with a deburr tool or 45° abrasive point to handle the ID burr. The most unpleasant part about this is the fact that a great many shooters do not have the experience to tell false positive pressure, from actual pressure. So they end up chasing their tail in frustration for a long while before reaching out to me for help. Then once this problem is discovered, it's not trivial for someone without much experience to fix this on their own.

Hopefully this will help any of you that might encounter this in the future.

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Is it just the lighting or is your firing pin hole out of round?

 

[orkan]

Is it just the lighting or is your firing pin hole out of round?

Lighting.

 

[RidgeTop]

There seems to be a plague of bad bolt faces slipping out to the world lately. I've had no fewer than 5 conversations about this in the past 2 weeks alone. So I figured a public service announcement was necessary. Some of you may remember an article I wrote many years ago describing how to read pressure signs. I make mention of this issue in that article. Here it is for those that haven't read it:

Understanding Pressure :: Primal Rights, Inc

Reading pressure is a required skill that all shooters must have. Whether you are shooting factory ammunition or your own handloads, you absolutely must be able to detect and interpret pressure signs on your fired brass.

www.primalrights.com

I just received a new rifle that had the false positive issue, so I wanted to document it here. Folks, this is why it's so important to use a smith that will catch issues like this before they get out to you. These days, Taylor Stratton at Stratton Custom Rifles in Delta Colorado does my work... and one of the main reasons I chose him is that he will properly evaluate and fix each action he builds on as a matter of course. Many smiths rely on the action manufacturers to catch issues, and they simply do not.

The issue at hand is this:

My brand new rifle, was demolishing my cases... making it appear as I was running a massively over-pressure load. The action I'm using is a brand new Lone Peak Fuzion. The action did not have the ignition properly timed, nor did any of the other burrs or issues get fixed. (was not built at SCR) I have vast experience with 22 creedmoor, so I knew that 40gr of H4350 behind a 70gr berger was not a hot load, and was not over pressure. This is further evidenced by the fact that the primer is not cratered, not flat, and there are no other defining signs of pressure beyond the massive ejector wipe.

I've run into this issue several times before, and while it is sad that a top level action such as a Lone Peak Fuzion exhibit this problem... it's very obvious what is going on. When the hole for the ejector was drilled, the bolt face was not cleaned up afterward, leaving a massive burr around the ejector hole. The proper fix is to fully indicate the bolt in true, and then run a cleanup cut on the bolt face. However, this needs to be done before the barrel is installed, as it will alter headspace. So, in order to fix it... I use a special cylindrical stone, and twist it across the surface by hand.

The stone I use to fix the issue.

Here you'll notice the burr is removed, as evidenced by the shiny ring around the ejector pin hole. Not an easy area to work in manually.

I've seen this on many actions in my career... and it's a shame, because all would be needed is for the final bolt face cut to be performed AFTER the hole is drilled for the ejector... then a quick twist in the ejector pin hole with a deburr tool or 45° abrasive point to handle the ID burr. The most unpleasant part about this is the fact that a great many shooters do not have the experience to tell false positive pressure, from actual pressure. So they end up chasing their tail in frustration for a long while before reaching out to me for help. Then once this problem is discovered, it's not trivial for someone without much experience to fix this on their own.

Hopefully this will help any of you that might encounter this in the future.

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My advice is stay away from Casino's, you have terrible luck. In over 60yrs of shooting over 150 rifles+ (many new) I have never found that defect. jim

 

[Chaddrx]

I just bought a new defiant anti x. I don't have as much of a swip like you show, but have a little ejector mark at very low charge weights. Could this be the same issue just presenting differently?

 

[orkan]

I just bought a new defiant anti x. I don't have as much of a swip like you show, but have a little ejector mark at very low charge weights. Could this be the same issue just presenting differently?

Absolutely. Ejector ring, as you show... is a much more frequent demonstration of the problem. The massive destruction shown in my picture is only the worst instances. Mild ring like you show is much more common, and is likely a very small, but very sharp burr.

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