It can be difficult to determine if the loads you take to the range for testing are getting into the red zone as far as pressure.

ANSWER: take your shell holder along, and check for fit. If pressure is much over safe limits, the place you will see it is in the web; ie case head expansion. That is where the case fits in the shell holder. If it does not want to go, you have a problem brewing.

Got the tip from some of the 1000 yard shooters on Accurate Shooter.

quote:

Originally posted by Idaho Sharpshooter:
It can be difficult to determine if the loads you take to the range for testing are getting into the red zone as far as pressure.

ANSWER: take your shell holder along, and check for fit. If pressure is much over safe limits, the place you will see it is in the web; ie case head expansion. That is where the case fits in the shell holder. If it does not want to go, you have a problem brewing.

Got the tip from some of the 1000 yard shooters on Accurate Shooter.

uhmm --- if your RIM (regardless) expands, you have more of a problem than casehead expansion - which generally doesn't touch the shellholder...

where one measures casehead expansion (CHE) USUALLY goes INSIDE the die....

this is satire, right?

CAUTION

Even if your case does fit the shell holder, it may still have been exposed to excessive pressure / hot load.

Here is what I found with hot loads when developing loads for modern action rifles (Sako, Winchester, Remington) in 6.5X55 and 280 AI where good book data was not available 15+ years ago.

Primer flattened with hat brim on removed primer

Ejector port shaves off brass from case head - Sako, Remington or similar push feed rifles

Loose primer pocket - easy seating of primer but primer does not fall out

All above cases fed into shell holder but micrometer measurements showed excessive expansion

If you cannot actually measure the pressure, the only safe way to know about a safe high velocity load is to measure the case expansion - not just once but follow the correct procedure accurately.

I used to measure every load - 10 shots and total 4 or 5 charges for each load development. At least 50 measurements for each load.

My final loads gave me 10 or 11 reloads from new cases and safe, accurate loads.

No free lunch in this business.

Be safe and have fun.

"When the wind stops....start rowing. When the wind starts, get the sail up quick."

With all due respect, this is a bad idea.

Let's see when I was pushing my cartridges I would measure for .0005 just in front of the extractor rim on non-belted cases. If the head expanded enough that it wouldn't slip into a shell holder I would bet serious you are in the serious pressure range.

I don't like the shell holder idea.

Rich

Surely you own a 1" micrometer

jeffe,et al,

No offense meant; but the crew at Brian Litz's shop have won more 1000+ yard matches this year than you all have likely ever shot in your life.
And, they loaded all of their ammunition for the Ko2M competition, where, iirc, they finished 1,2,3,4, on a Dillon 650 press.

This was a courtesy post. Take it in the manner it was intended.

If a case does not fit into a shell holder after being fired, then it had a lot more pressure than I would consider safe.

With all due respect Rich that is a complete fallacy. Just look at a case in a shell holder, the only part of the case touching the 'jaws' of the shell holder is the bottom of the extractor groove. The very rear of the case base where the extractor groove taper meets is approximately 0.5mm above the top flat of the shell holder and the web of the case, that part of the case wall above the solid base which is usually measured for expansion and where incipient case head separation is first seen, is approximately 5mm above the shell holder flat.

The only way a case can be a no go in a shell holder due to pressure would be if the extractor groove expanded which by this stage there would have long gone been a full head separation. The extractor groove is not supported in the chamber and is unaffected by pressure unless there has been a blowup.

I haven't won 1000 matches this year, guess I better start taking my shell holder. Maybe a whole set and have go no go gauges? Certainly if you are going to reload at the range, take your shellholder. Press is useless without it.

My pressure signs:

Primer flattening
Ease of extraction
Comparing actual velocity to predicted/expected velocity

and later ease of FL sizing, but:

Some primers are more easy to flatten than others.

Some brass is more difficult to extract than other. Prime example:

In my 500 S&W revolver, even Magtech/CBC factory loads are "not easy" to extract. Even lightest reloads are "not easy" to extract too. It can make you scare that something is wrong. Only wrong is a junk brass.

On other hand, full loads in Starline brass are easy to extract as .38 Special target loads.

But "the thing" with shell holder? It has to be insane pressure and all mentioned above must be happening for a while.

Jiri

Don't see how winning 1000yd matches has anything to do with a suggested method to measure pressure.

Unless I'm, reading my SAAMI drawing incorrect using a normal 06 case. Case head is .473-.01 the extractor groove allows .02. A shell holder has to fit the full range. Most would say you have pressure limit when you hit. .0005 on the head in front of the extractor groove.

I will agree if after fireing a case doesn't fit you have a PRESSURE PROBLEM. But you had it way before that.

Jees, I had to use a 2x4 to beat the bolt open! It might have been a hot load. I know, I'll use a shell holder to check!

What a crock.

And who cares what press they used?

In addition to being a complete fallacy, it's complete bullshit.

Not sure what article Rich is quoting but found this article on AccurateShooter. It references using the shell holder but as we are saying says when the case won't fit you are at "extreme" or "way over" pressure.

"""RELOADING TIP–Use Shell-Holder to Monitor Case Expansion

During load development, it’s important to check cases for signs of over-pressure. While you need to pay attention of a variety of factors, such as primer flattening and stiffer bolt lift, one sure sign of over-pressure is excessive case swelling at the web. A quick and easy way to monitor this is to bring a shell-holder (for your rim size) with you to the range. If a fired case won’t slide into the shell-holder easily, the diameter of the extractor groove has grown excessively and you know your load is much too hot… you’re way over-pressure.

Take note — if you get to the point that your case is hard to slide into a case-holder, your load is way hotter than it should be. So consider this an “extreme” measuring method. You should watch for other signs of pressure as well. As a rough rule of thumb, if we had a case that would not fit easily into the shell-holder, we would reduce the charge by at least 3/4 grain in a small case and 1.5 grains in a magnum case (and you may need to back-off the load further)."""

quote:

Originally posted by Idaho Sharpshooter:
It can be difficult to determine if the loads you take to the range for testing are getting into the red zone as far as pressure.

ANSWER: take your shell holder along, and check for fit. If pressure is much over safe limits, the place you will see it is in the web; ie case head expansion. That is where the case fits in the shell holder. If it does not want to go, you have a problem brewing.

Got the tip from some of the 1000 yard shooters on Accurate Shooter.

Idaho,

I'm not sure why you're pushing your PSIs and velocities so high...?

For long range accuracy, you need consistent muzzle velocities and SDs 10 or below. I've found this occurs with PSIs in the 55-60,000 range associated with moderate muzzle velocities. High PSIs tend to produce more variable muzzle velocities and are prone to PSI excursions causing stuck cases and/or blown primers.

IMO, with accurate range finders super-high muzzle velocities add very little to your long-range effectiveness. Litz has shown this with WEZ analysis.

AIU

Thanks Saeed and Ramrod340.

Tell you all a little story.

Many years ago there was a gentleman who was a partner in a barrel company in Texas. He had what he told me was a "warm load" for a 308 Winchester he hunted deer with. He was telling a friend at Winchester how flat it shot, and the friend asked him to send a few rounds to their shop.

The friend called him a week or so later and told him to STOP!!! shooting any of that ammunition. Their pressure testing equipment recorded pressures in the low 80,000 PSI range. Brass is close to a plasticus state at that kind of pressure level.

As far as testing new ammunition, yes, I often do load work at the range. I have a 100% safe method I learned from another 1000 yard shooter. But some of you would not understand it, and a few of you would disparage it because I was the one who shared it.

Ray,

everywhere I shoot Rockchucks and the occasional coyote the yardages vary, and are unmarked. And, unlike a registered match, they move around. So, I generally have to estimate the distance, and hold over or click up. Quickly. And yes, I do own a pair of Geovid 10x42 laser range finder binoculars.

AI,

point well taken.

However, Brian's work does not revolve around first shot hitting a furry little target 6" wide and 12" tall at a range of 200 to as far away as I can find him in my spotting scope. Especially one that moves around.

His laser range finder cost more than you or I make in a year, and I do not have a three or four man spotting/support group. When engaging an enemy soldier, you can 99% of the time, count on him to remain stationary for a few seconds at some point. That's when you kill him.

I was a shooter in my Ranger Company in RVN my second tour. In that scenario, I might have had several VC/NVA in sight. If I just hit one, the rest were immobilized for some time. My scenario here is different.

As an example, imagine a rifle match with a time clock.

All of the targets are painted white, 12" round plates. There are 20 of them at random (unmarked) distances, from 300 to 1200 yards. You have sixty seconds to engage as many as you can. Farther ones have a higher value for score.

Going to score well if you use your range finder and click up and down according to your ballistics program on each target?

In the early 1990's there was a gentleman, Dick Thomas, who owned Premier Reticle in VA. I sent him a drawing of a custom reticle, along with a boost request for a 6.5-20X Leupold.

It had windage lines 5 moa left and right of the vertical cross hairs, and 1/8moa dots 3 and 6 moa above the crosshair junction, and 3, 6, and 9moa low. He also boosted it to 18-42X and converted it to first focal plane reticle.

Knowing Rockchucks were 5-6" wide and 10-12" tall, the dot spacing let me employ it as a range finder of sorts. Target would be four dots tall at 100, down to one dot tall at 400. Farther, and I could split the dot spacing.

With my scope, you might have gotten half of them, maybe a few more in 60 seconds.

It's a different game...

quote:

The friend called him a week or so later and told him to STOP!!! shooting any of that ammunition. Their pressure testing equipment recorded pressures in the low 80,000 PSI range. Brass is close to a plasticus state at that kind of pressure level.

Where is plasticus state, is it near Idaho?

quote:

Originally posted by carpetman1:

quote:

The friend called him a week or so later and told him to STOP!!! shooting any of that ammunition. Their pressure testing equipment recorded pressures in the low 80,000 PSI range. Brass is close to a plasticus state at that kind of pressure level.

Where is plasticus state, is it near Idaho?

I was thinking that you had to be liquored up really bad to be in a plasticus state.....much more over that and you hit rubberous

Has anyone tried measuring extracted primers to get a feel for the loads?

I did this for a few rifles and found it very interesting.

Firstly I use only Fed 210 primers.

Secondly I partial FL size and so the head space is on the shoulder and so the primer does not back out & slam back like a factory round would. Yes, I know that ALL primers will back out & go back in - to varying degrees .....

I found that any formation of a distinct "hat brim" on the primer resulted in a perceptible change in re-seating primers. They just go in a bit easier. That indicated that the pressure was too high irrespective of soft or hard brass.

I even took a series of measurements for round primers of light starting loads, average loads, top loads & hat brim loads. I also took photos but cannot find them. Chronograph was always used in conjunction with tests.

I got a real good understanding from doing that exercise. Strangely I have never read about that in any other source.

I never load close to the limit, although I do understand why it is sometimes necessary.

If I did, I'd use a digital micrometer.

Reading primers and monitoring velocities has always worked for me. And 9 times out of 10 there will be a discernible correlation. But I especially watch velocities for a given load and use pressure data in manuals and factory published velocities as a basic benchmark reference. Sometimes manuals arent always right, or applicable. But the laws of physics dont lie. If you are getting 2700 fs from a 35 Remington, you are lucky to still be alive..

I too have relied on reading primers and taking notice of any discernible increase in resistance to the bolt handle lift, the equivalent to the latter for a double would be resistance in opening the gun. An imprint or signs of a bolt face ejector on the case head is also a sure indication of too higher pressure. A chronograph will provide velocity data only, as some rifles will give high velocities with no signs of pressure with a particular load while other rifles with the same load will give high pressure signs as outlined above.

Reading primers has to take into account the primer brand, so if using the same primers as a load is worked up to the point of other pressure signs becoming apparent e.g. ejector marks, stiff bolt lift, incipient case head separation, then a good comparative record will be obtained of primer flattening.

The photo below shows a 7x61S&H cartridge case from a Norma factory load fired in a Schultz and Larsen rifle. Unfortunately the glare in the photo does not allow the small NP imprint to be seen on the primer but it is a once fired factory case with a Norma primer. The S&L rifles with their massive rear locking lugs have been tested to 120,000psi with no discernible issues from such high pressure. The bolt in the rifle in which the cartridge was fired would not close on a no go gauge. The bolt lift was slick and the case went on to be reloaded many times when sized to seat on the shoulder as belted cases should be if reloading them.

So the moral of the story is that primers do provide a viable/reliable method of tracking pressures but other information needs to be known i.e. had I given that case to most reloaders and not told them it was from a once fired factory round, 100% would have said pressure was way too high or the rifle had too much head-space. I loaded 160gr bullets to a chronographed 3000fps, just short of the factory MV of 3040fps in the same rifle using CCI 250M primers that showed some flattening but not as severe as the Norma primers.

Eagle 27.
I also use primer condition along with the understanding that primer cup hardness and thickness must be considered.I use a lot of CCI 34 primers which are suppose to be anti slam fire. My high pressure jugements, along with primer appearance, also include bolt handle lift.
roger

I have an 06 that gives up about 150 fs more than any other 06 I have ever had with no pressure signs. So I roll with it, but carefully and cautiously.

One aspect of "reading" primers is the flattened primer and its firing pin indentation.

A sloppy chamber will always give really flat primers. This is because the primer comes out at recoil and gets slammed back against bolt face. Greater the slack, flatter the primer. But the firing pin indentation will be normal.

A hot load with a neck sized case will give a flat primer but firing pin indentation will be cratered - with the primer metal forming a raised ring around the punch mark as the metal flows into the firing pin hole on the bolt face.

In other words a hat brimmed primer with a cratered indentation is a sure sign of high pressure.

BTW I have also found rounded primers with cratered indentation. This IMHO is due to longer firing pin under low pressure.

People are talking about HIGH PRESSURE.

What is too much pressure...

60,000
65,000
70,000
75,000
what

I'm curious how reloaders define excessive pressure.

quote:

People are talking about HIGH PRESSURE.What is too much pressure...60,00065,00070,00075,000what

Depends

Look at SAAMI specs

222 Rem has a max of 50,000 PSI
243 Win is 60,000 PSI
270 Win & 270 WSM are 65,000 PSI
375 H&H is 62,000 PSI

My efforts to go above the max loads in the 222 Rem resulted in blown primers. I learned that lesson in the first 6 months of reloading.

Understanding the complex variable that determine pressure in a rifle chamber is critical.

It is exponential and the variables are NOT linear. For example an increase of 2% powder charge can result in 5% or more increase in pressure but velocity may only go up by 1%.

Increasing bullet seating by 0.005 inch closer to the lands may increase pressure by 10%, if you are already close to the lands to start with.

Be safe. No free lunch in this business.