Home Forums Hunting & Shooting Ask The Gunwriters Max load development

That book is a good read well worth the time. There are 2 that I highly recommend. First is “The Bullets Flight. From Powder to Target” by Dr. Mann. Excellent read..
Next would be “The Complete Guide to Handloading” by Phillip B. Sharpe.

That's funny, I just downloaded the kindle version of Twenty Two Caliber Varmint Rifles.

It is the old skills that are disappearing. The so
is common sense and practicle solutions .
Our heads are full of useless information not practicle, I would of like to meet Ed but had my Uncle Gabe

Trying for max loads is just silly. If you want more speed from a 30-06, trade it in for a .300 WM. If you want still more, get a .300 Weatherby.

The primer popping method is, IMHO, really stupid because it depends on the primer hardness. I used to shoot .223 in matches using Winchester cases only. I could get about 10 reloads with the old WSR plated primers but after 4 or 5 with Remington unplated primers, they would fall out. Maximum loads in neither case.

I want everyone to put on their thinking caps. This is about chronographs.

While doing some research about an Ontario gunsmith, I came across a letter written by Jack O'Connor about some cartridge tests using Vernon Speer's chronograph. I presume it was the company chrono. It was called the "Potter Counter Chronograph". This was probably made by the Potter Instrument Company.

Does anyone have any information about this chronograph and the company? It appears to be something that would have been used in the late 1940s into the 1950s. References to Potter Chronographs were made in various military documents of the time.

Can’t find that, but in his 1942 book Phil Sharpe had a chapter on chronographs. The most notable being the Le Boulenge’ drop rod and the Chronoscope used by Remington in 1940. But I have found some interesting reading dating to early 1840’s chronograph.

https://en.m.wikisource.org/wiki/1911_Encyclopædia_Britannica/Chronograph

In the Le Boulengé chronograph (“Chronograph le Boulengé,” par M. Bréger, Commission de Gâvre, Sept. 1880) two screens are used. The wire of the first forms part of the circuit of an electromagnet which, so long as it is energized, supports Le Boulengé.a vertical rod called the “chronometer.” Hence when the circuit is broken by the passage of a shot through the screen this rod drops. The wire of the second screen conveys a current through another electromagnet which supports a much shorter rod. This “registrar,” as it is called, when released by the shot severing the wire of the second screen, falls on a disk which sets free a spring, and causes a horizontal knife to fly forward and nick a zinc tube with which the chronometer rod is sheathed. Hence the long rod will be falling for a certain time, while the shot is travelling between the two screens, before the short rod is released; and the longer the shot takes to travel this distance, the farther the long rod falls, and the higher up on it will be the nick made by the knife. A simple calculation connects the distance through which the rod falls with the time occupied by the shot in travelling over the distance between the screens, and thus its velocity ascertained. The nick made by the knife, if released while the chronometer rod is still suspended, is the zero point. If both rods are released simultaneously, as is done by breaking both circuits at once by means of a “disjunctor,” a certain time is consumed by the short rod in reaching the disk, setting free the spring and cutting a nick in the zinc; and during this time the long rod is falling into a recess in the stand deep enough to receive its full length. The instrument is so adjusted that the nick thus made is 4.435 in. above the zero point, corresponding to 0.15 sec. This is the disjunctor reading, and requires to be frequently corrected during experiments. The instrument was modified and improved by Colonel H. C. Holden, F.R.S. For further information respecting formulae relating to it see Text Book of Gunnery (1857)

https://eugeneleeslover.com/USNAVY/CHAPTER-XV-PAGE-1.html

Aberdeen Proving Grounds 1937

1518. Boulengé chronograph. (See Fig. 1502.)-This instrument, invented many years ago by an officer of Belgian Artillery and developed abroad, is still in common use at proving grounds in all countries. It measures the time interval by recording the difference in time of fall of two rods, suspended by electromagnets. The longer (chronometer) rod, being released when the projectile breaks the first screen, is nicked in its fall by a knife released by the shorter (registrar) rod whose electromagnet is in series with the second screen.


Anyways between those 2 it seems they had some various ways to chronograph artillery and bullets back to 1840. Interesting reads.

I like to maximize the chamberings I have with my handloads. I use a chronograph at home for this purpose but the single greatest pressure indicator are my Wilson case gauges. If the case doesn't easily slip in and out seamlessly, I review it closely and if the head expanded at all it is discarded. I no longer neck size( or partial neck size)
A chrono is fun, but not essential to this shooter.
My way

I believe the Potter chronograph worked just like more recent models--measuring the time of flight between breaking two screens placed a precise distance apart--except it used vacuum tubes before transistors (solid state) were invented. It cost around $5,000 in the '50s, which meant that individual shooters simply could not afford one. Back then a lot of wildcatters had exaggerated opiniions of he velocities they were getting and even some manufacturers of factory ammo "lied" (to put it delicately) about the velocity of their products.

Modern chronographs use a crystal oscillator as the time base. The Potter probably used a circuit called an "astable flip flop," consisting of two vacuum tubes and some other components, which would have meant that it was not as accurate due to temperature changes. Needless to say, the Potter was very large and cumbersome.

The first electronic ballistic chronograph was invented by Kiryako ("Jerry") Arvanetakis in the 1950s. As consulting engineer under contract by NACA (later NASA), he was asked to find a way to accurately measure the velocity of various projectiles fired at hyper-velocities into a variety of engineered materials in anticipation of manned space flight. His first design was an open rectangular frame of square aluminum tubing with a screen of fine copper wire at both ends. Breaking the first wire started charging a capacitor, breaking the second wire stopped it. Measuring the accumulated voltage and knowing the rate of charge the elapsed time could be accurately calculated.

I never heard of that one. I would be surprised if it were more accurate than 2% or so because charging a capacitor is just not a very good method. The astable flip flop using vacuum tubes as a time base is much better and was available in the 1950s. All chronographs since 1960 used a crystal oscillator as the time base. Worked better and cost less.