HIGH PRESSURE LOADS by John Linebaugh

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JimT
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HIGH PRESSURE LOADS by John Linebaugh

Post by JimT »

(This was written by John Linebaugh more than 20 years ago. It is more applicable now than ever.)

HIGH PRESSURE LOADS
by John Linebaugh

Time-proven technology along with metallurgical and propellant advancements have given the modern shooter the greatest boost in performance ever witnessed in history. Every serious sixgunner knows the .357 was the first "high pressure" loading in the great country. It stood as KING for 20 years until it was replaced with the .44 Magnum. Both of these rounds were loaded to approximately 40,000 CUP levels.

Dick Casull started the very first experimentation with real super guns in the late 1950's and after 20-plus years of work and experimentation finally realized his dreams come true when Freedom Arms began producing his fine .454 Casull revolver. Others followed the "high performance" game and we now have the greatest assortment of sixguns and 5-guns to be found in the world available to us.

Many shooters stayed with their standard .44 and .41 Magnum revolvers but over the years have "crept up" on heavier loads, many through their own experimentation or the urging of other's printed results. The trend now is for heavier bullets and higher velocity. This is all fine and well if the overall picture and results are kept in perspective. But one one must remember: Nothing come for free - and, Walk! Don't run! in the search for increased performance. Perhaps this sounds a bit dogmatic coming from the maker of some of the biggest-bore revolvers in the world. But in 10 years of sixgun building and experimentation we have seen a few results most shooters will never see.

Hardly a day goes by here in the shop that we don't receive a phone call that the subject doesn't finally turn to heavy bullets in .41 and. 44 Magnum revolvers. Many seriously ask "Why can't I just 'heat up' my .44 and keep using it?"

The answer is, you definitely can. But keep in mind the gun and caliber limitations. Just adding more powder isn't the answer. Just getting more pressure isn't the answer. And often times even if you do gain more velocity through your efforts, it still may not be the answer to increased performance. About 8 years ago I had just finished a .45 Colt on an old Abilene frame. Barrel length was 7 1/2 inches and the 6-shot cylinder was oversize in diameter and full frame length. Our load was 30 grains of Hercules 2400 and 225 gr. Speer JHP. Our goal was 2000 fps, just like Dick Casull called for in the .454. Velocity was in the range of 1700 fps so more powder was needed. We ended up shooting 36 grains of 2400 and our top velocity was 1960 fps. We never did reach the magic 2000 fps goal, but did knock several nickel-sized corks out of a 5/16' steel plate.

From what I know today after studying pages of pressure-tested load data and comparing powder performance and pressure curves, I believe we were shooting loads well into the high 50,000 CUP level that night. This kind of pressure in this barrel length should have given us 2000 fps +. But it didn't. The gun was tight and built right. It did its part. It was a few years later before I fully understood what was taking place. In this application the lightweight slug wasn't offering enough resistance to make the powder work to its full potential. It has been our findings that it is much easier to get more velocity easier with heavier slugs than with light ones.

More pressure is generated of course, but the powder works better and more consistent results are the norm. But the serious condition exists when we add more powder and the pressures go up, but we don't get more velocity in return. Impossible you say? Modern powders are great propellants but have their limitations. Each powder is designed to operate within a certain pressure level. If you apply said powder below its "happy" pressure level it will give disappointing results. Hangfires and even misfires can result. Load the same powder in an application that is not harmonious with its personality and it will develop pressure well off the scale compared to the velocity you get in return.

This application or condition can be created by caliber; by too heavy a bullet; or (a REAL culprit) too heavy a bullet that is seated too deeply into the case. All three of these conditions add up to one major overlooked condition and that is "capacity". CASE CAPACITY. All powders need enough "room" to work properly for their application. By using a lot of slow-burning powder under extremely heavy bullets, results can vary from excellent to questionable.

The trend among handgun shooters today is heavier and heavier slugs. All cartridges have limitations and balance points. I've said it before that the 300 to 320 gr. absolutely the maximum weights I will use in the .44 caliber. The 350 gr. weights are the maximum in the .45 Colt. With weights beyond this in guns of a "NORMAL" cylinder length (which limits the overall loaded cartridge length) length begins to crowd the case capacity and seriously affect the volume the powder has to work in.

Some may argue that their charge of 296 will act the same no matter how it is compressed. And it is true that this powder and its brother H-110 work best under mild compression. But when we push our powder charge well into the bottom of the case and cork it with a slug too long and heavy for that caliber we are changing several things.

We change the "dwell time" - the time the sits in the chamber (after the powder is lit) before it starts to move. The more time taken here the sharper the pressure curve becomes. The reduced capacity limits the working area of the powder which means it has to try and do its normal amount of work in a less than normal space.

We also change the burning rate. With retarded bullet movement due to excess bullet weight the burning rate of the powder increases (it burns faster) generating more gases and vicious circle is created.

And we change (or "shift") the problem area to the gun. The quick pressure curve that now lasts longer than normal due to increased dwell time, and the faster burning rate which generates more gas and more pressure than normal, hits the gun in the cylinder right at the base of the bullet. I have seen many cracked and blown cylinders to prove the blowup starts in the bolt notch. The great part of the pressure is put on a small part of the cylinder, usually near the bolt notch. With a normal-type load of proper bullet weight, not seated too deeply in the case, the pressure curve should flow through the cylinder well into the barrel throat and frame.

For a moment think of your cylinder and barrel frame area as a stack of washers with chambers and bores through them. If pressure was exerted through the whole stack, say for nearly 2", wouldn't that be stronger and safer than trying to apply the same amount of pressure on only the first few washers?

Thousands of rounds of testing here has proven to us that gun life is better with safe heavy loads using slow powders than it is with light loads using fast powders. Case life agrees. The fast powders "hit" the gun very quickly and the slow powders "take up the slack" so to speak, slower and with less hammering effect.

I have measured one of my early .500's on a Ruger frame recently that I know for certain has had over 1000 Proof-Class loads and a few hundred maximum loads. I cannot measure or detect any movement or wear in the gun. All loads used H-110 or WW-296 powders.

When we talk of "Proof Loads" here our pressures are in the mid to high 40,000 CUP level. Still well within the bounds of H-110 or WW-296 to operate properly and in a normal manner. Some .44 Magnum loads I see recommended, the pressures, due to bullet weight and case capacity, are clear off the scale for this caliber. I have seen pressure data from special pressure guns that proved to me the loads were not operating properly. By overloading any gun we prove nothing and gain little. Overload slow powders too much and soon your gun shows the same signs it will show with fast powders. However, instead of working with mild pressures we are generating excessive pressures.

The visible signs may not be the only damage done to the gun either. Metal fatigue goes unnoticed until something serious happens. The blast and sharp recoil patterns I find with overloads are the worst part of the shooting game, to me. The first few head of big game I shot with a handgun were with full power loads. The few I have taken were with about 1/2 power loads. They were taken just as quickly and humanely as before. Once we completely penetrate a target we cannot do any more. Heavier slugs and more speed help a great deal to accomplish this goal, but everything has its limitations.

In this time when hunters are looked over very seriously and often times unfairly we need to put out best image forward. Safe hunters, safe gunhandlers, and safe HANDLOADERS are needed to teach our young shooters of tomorrow.
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Scott Tschirhart
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Re: HIGH PRESSURE LOADS by John Linebaugh

Post by Scott Tschirhart »

Interesting reading Jim. The only guns I push real hard these days are .357 Magnum and .327 Federal revolvers. They generally perform well when stepped on pretty hard.

But for my hunting purposes I have settled on pedestrian loads in larger bore revolvers. In the .45 Colt 8 gr of Unique behind a 270 SAA bullet clocks about 930fps and the Skeeter load of 7.5 gr of Unique behind a 250-250 grain bullet clocks about the same in my .44 Specials.

I don’t need more penetration as these loads will shoot right through a full sized cow.
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Re: HIGH PRESSURE LOADS by John Linebaugh

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Scott Tschirhart wrote: Wed Feb 22, 2023 3:37 pm I don’t need more penetration as these loads will shoot right through a full sized cow.
Yessir! I was talking with John Linebaugh a couple weeks ago. At the Seminar he puts on in Cody they do a 1000 yard Buffalo shoot with handguns. His standard load for that is around 1100 to 1200 fps.

The Lord willing I will be in Cody for it this year!
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Re: HIGH PRESSURE LOADS by John Linebaugh

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Excellent write-up! 👍🏻
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Re: HIGH PRESSURE LOADS by John Linebaugh

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John Linebaugh writes with more fundamental common sense and understanding of the physics of bullet propulsion in handguns than any other gun writer. I have come back to his piece on "The ".45 Colt -- Dissolving the Myth" again and again.
https://www.johnlinebaughcustomsixguns.com/writings
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Re: HIGH PRESSURE LOADS by John Linebaugh

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Scott Tschirhart wrote: Wed Feb 22, 2023 3:37 pmIn the .45 Colt 8 gr of Unique behind a 270 SAA bullet clocks about 930fps and the Skeeter load of 7.5 gr of Unique behind a 250-250 grain bullet clocks about the same in my .44 Specials.

I don’t need more penetration as these loads will shoot right through a full sized cow.
So true. A Hard-Cast bullet in a 44 or 45 caliber going about 1,000 fps pretty much keeps on going, and makes a nice big hole (or more often, TWO nice big holes) to deflate the lungs, bleed out quickly from, and (though the first two thinigs mean it is rarely needed), leave a blood trail for tracking.
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Re: HIGH PRESSURE LOADS by John Linebaugh

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Bill in Oregon wrote: Wed Feb 22, 2023 5:45 pm John Linebaugh writes with more fundamental common sense and understanding of the physics of bullet propulsion in handguns than any other gun writer. I have come back to his piece on "The ".45 Colt -- Dissolving the Myth" again and again.
https://www.johnlinebaughcustomsixguns.com/writings
From that article I started re-thinking things:

“I have personally taken about 10 antelope and one Mile Deer with a .45 Colt. My boys have taken around 6 antelope and 5 mule deer with their .45 Colts. They use a 4 3/4” Colt SA and the handload is a 260 Keith at 900 fps. This load will shoot lengthwise of antelope and mule deer at 100 yards….”
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Re: HIGH PRESSURE LOADS by John Linebaugh

Post by Grizz »

Thanks very much for the discussion and the links. RE-read JL's article tonight and found this>
Screenshot 2023-02-22 182320-45 Linbaugh loads.png
I had a friend who was casting 320Gr plain base bullets, and I bought a bunch of them. Looking at my notes I see that I experimented with 296 between 21.0 to 21.8 grains, and settled on 21Gr because it was easy on the gun, easy on the hands, and a hammer on the deers. I did the testing blindly because no chrono, but payed attention to the forensics, penetration, and pen tests to arrive close to the 'balance point.'

According to Mr Linebaugh's article my fav, 405Gr, may be unnecessary, or past the balance point, I don't know.
But that load feels right in the RedHawk, so far, at 940fps. Which is wrong because of the defective cylinder and maybe throat too... I might have to buy a ballistic program to try to get more insight on Marshall's load.

gratifying to learn that my load was right in the range I wanted, on accident I suppose.

grizz
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Re: HIGH PRESSURE LOADS by John Linebaugh

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Thanks for posting this Jim. I read a bunch of JL’s writing about this and his penetration tests. What an amazing man.
I did a bunch of experiments with Lil’gun and heavy bullets in the 360 DW and this article really helped show why that powder performs the way it does. I learned it likes about a 90% case fill, a heavy bullet and a good crimp in the 360, 357, and 32-20.
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Re: HIGH PRESSURE LOADS by John Linebaugh

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We did penetration tests at the Dietz gun range one year when John had a seminar in New Braunfels Texas. Other than a particular elephant gun, the penetration winner was Big Nose Kate with a 520 gr Government bullet over 70 grains of GOEX Catridge. About 1100 fps but it penetrated 68 inches of wet newspaper, a pine 2x6 and bounced off another 2x6 that we nailed up at a 45 degree angle behind the first one.

The hole was so straight you could have run a rod through it.

We concluded that the bullet just wasn’t stressed that much on impact at that velocity so it maintained its integrity.

I think the same thing happens with bigger revolver cast bullets if they aren’t driven to maximum velocities

BUT I will be the first to admit that a .45 caliber bullet driven at 800 fps is not the equivalent of that bullet at 1400 fps.
Last edited by Scott Tschirhart on Thu Feb 23, 2023 8:27 am, edited 1 time in total.
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Re: HIGH PRESSURE LOADS by John Linebaugh

Post by JimT »

I was there Scott. I remember that ...and that elephant gun!
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Re: HIGH PRESSURE LOADS by John Linebaugh

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JimT wrote: Thu Feb 23, 2023 8:27 am I was there Scott. I remember that ...and that elephant gun!
Yes you were Jim! I had forgotten all about that. The most impressive thing to me was that video of those pistol bullets being fired across that big green field. Some went straight as an arrow and some went wild as they slowed down.
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Re: HIGH PRESSURE LOADS by John Linebaugh

Post by Bill in Oregon »

Scott, were the bullets that went wild of WFN design? I have heard they lose accuracy beyond 100 yards or so compared to the LFNs but no first-hand experience.
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Re: HIGH PRESSURE LOADS by John Linebaugh

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My tests with the WFN's in the 454 showed me that they have to be run really fast to retain accuracy out to 300 yards. If I ran them at the velocities of the LFN lighter loads they would not stay in a 30 foot circle at 300 yards. That was running 1100 fps or slower.

I don't remember too much about the video John showed but I think .. and I may be wrong ... but I think some of the bullets going crazy at the terminal end of their flight were swc's.
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Re: HIGH PRESSURE LOADS by John Linebaugh

Post by Bill in Oregon »

Useful information Jim. Thank you.
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Re: HIGH PRESSURE LOADS by John Linebaugh

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They were shooting a number of different bullets and I don’t remember details other than the old Lyman Keith bullets sailed true.

Some of the bullets went in crazy directions a few hundred yards out and you could watch the bullet bases reflecting the sun as they flew.
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Re: HIGH PRESSURE LOADS by John Linebaugh

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Each powder is designed to operate within a certain pressure level. If you apply said powder below its "happy" pressure level it will give disappointing results. Hangfires and even misfires can result. Load the same powder in an application that is not harmonious with its personality and it will develop pressure well off the scale compared to the velocity you get in return.
This was my "take-away" from this article, and I may have seen this play out with Blue Dot in my very large 43 Mauser case. I was trying to reduce the velocity with my black powder 485 grain pure lead bullet with Blue Dot to less than 1150 fps. When I did so, I started to get erratic velocities through my chronograph. It was clear to me that Blue Dot needed more pressure to work right.

Thanks Jim, for a very good article and reminder.

-Tutt
Last edited by CowboyTutt on Fri Feb 24, 2023 4:44 am, edited 1 time in total.
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Re: HIGH PRESSURE LOADS by John Linebaugh

Post by piller »

The science might seem to change, but it really doesn't. What changes is the variables. Lots of fun to read things like this.
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Re: HIGH PRESSURE LOADS by John Linebaugh

Post by 450 Fuller »

First rate.
JLs knowledge and writing has caused me to re-think my 45 Colt loadings in
both my Ruger SA and two New Service Colt revolvers. The
NS Colts have their own pressure limitations but are supremely accurate.
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Re: HIGH PRESSURE LOADS by John Linebaugh

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John built me a .500 Linebaugh back in 2000. I beat my hands up badly trying to learn to control that gun.

These days my tastes are much more pedestrian.
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Re: HIGH PRESSURE LOADS by John Linebaugh

Post by Walt »

I would rather shoot my FA .454 Casull with full power loads than my 4" model 29 with full power loads. Double action revolvers hurt to shoot these days.
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