December 27th, 2018

Chronos by The Numbers — Tips on ES, SD, and Sample Sizes

USAMU Marksmanship Unit Velocity Chronograph Testing Sample Sizes

The U.S. Army Marksmanship Unit (USAMU) regulary publishes “how-to” articles on the USAMU Facebook page. One informative “Handloading Hump Day” article covers chronograph testing and statistical samples. We highly recommend you read this article, which offers some important tips that can benefit any hand-loader. Visit the USAMU Facebook page next Wednesday for the next installment.

Chronograph Testing — Set-Up, Sample Sizes, and Velocity Factors

Initial Chronograph Setup
A chronograph is an instrument designed to measure bullet velocity. Typically, the bullet casts a shadow as it passes over two electronic sensors placed a given distance apart. The first screen is the “start” screen, and it triggers an internal, high-speed counter. As the bullet passes the second, or “stop” screen, the counter is stopped. Then, appropriate math of time vs. distance traveled reveals the bullet’s velocity. Most home chronographs use either 2- or 4-foot spacing between sensors. Longer spacing can add some accuracy to the system, but with high-quality chronographs, 4-foot spacing is certainly adequate.

Laboratory chronographs usually have six feet or more between sensors. Depending upon the make and model of ones chronograph, it should come with instructions on how far the “start” screen should be placed from one’s muzzle. Other details include adequate light (indoors or outdoors), light diffusers over the sensors as needed, and protecting the start screen from blast and debris such as shotgun wads, etc. When assembling a sky-screen system, the spacing between sensors must be extremely accurate to allow correct velocity readings.

Statistics: Group Sizes, Distances and Sample Sizes
How many groups should we fire, and how many shots per group? These questions are matters of judgment, to a degree. First, to best assess how ones ammunition will perform in competition, it should be test-fired at the actual distance for which it will be used. [That means] 600-yard or 1000-yard ammo should be tested at 600 and 1000 yards, respectively, if possible. It is possible to work up very accurate ammunition at 100 or 200 yards that does not perform well as ranges increase. Sometimes, a change in powder type can correct this and produce a load that really shines at longer range.

The number of shots fired per group should be realistic for the course of fire. That is, if one will be firing 10-shot strings in competition then final accuracy testing, at least, should involve 10-shot strings. These will reflect the rifles’ true capability. Knowing this will help the shooter better decide in competition whether a shot requires a sight adjustment, or if it merely struck within the normal accuracy radius of his rifle.

How many groups are needed for a valid test? Here, much depends on the precision with which one can gather the accuracy data. If shooting from a machine rest in good weather conditions, two or three 10-shot groups at full distance may be very adequate. If it’s windy, the rifle or ammunition are marginal, or the shooter is not confident in his ability to consistently fire every shot accurately, then a few more groups may give a better picture of the rifle’s true average.

(more…)

Permalink - Articles, Bullets, Brass, Ammo, Tech Tip No Comments »
August 26th, 2011

Shooters Buy Less Imported Ammo, But More Imported Guns

The National Shooting Sports Foundation (NSSF) reports that the USD value of U.S. quarterly imports of all sporting arms and ammunition declined 19% in the second quarter compared to the same period in 2010. From April to June, imports were $273 million, down from $337.1 million as reported in the same quarter last year. However, the decline was mostly due to a huge 42% drop in ammo imports. Imported long-gun sales (in USD value) have actually risen substantially. Sales of imported rifles rose 26.3%, from $27.1 million to $34.2 million.The shotgun category increased 23.4%, from $38.3 million to $47.2 million. The muzzleloader category posted a 7% increase, from $6 million to $6.5 million. Bucking the trend, handgun imports declined 13.1%, from $109.5 million to $95.1 million.

Imported Ammunition Sales Decline Dramatically
Over the past year, ammunition imports declined a whopping 42.2%, from $151.2 million (in Q2, 2010) to $87.4 million (in Q2, 2011). Moreover, the sales of imported shotgun shells fell 48.7%, from $5 million to $2.5 million. Apparently, now that there is a good supply of domestically-produced ammo, shooters are buying American again. Why has this occured? Currency fluctuations may be one reason. The declining value of the U.S. dollar, combined with rising shipping costs, have caused the price of imported ammo (and reloading components) to increase substantially in the past year. That has made domestic ammo more competitive price-wise. That is good news for U.S. ammo-makers. For additional research information and historical import data, visit nssf.org/research.

Permalink Bullets, Brass, Ammo, News 2 Comments »
July 19th, 2011

ATF Reports Rifle Production Down, Handgun Production Up

Americans are apparently buying more pistols but fewer rifles — that’s the trend suggested by the latest Firearms production statistics from the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). According to the ATF’s 2010 Interim Annual Firearm Manufacturing and Export Report, U.S. firearm manufacturers produced more than 5.4 million firearms in 2010. This represented a small (2.7%) reduction in total U.S. firearm production compared to 2009. However, the really notable statistic was a dramatic 18.8% reduction in rifle production. Rifle production decreased 18.8%, while handgun production increased 14.9%. That’s a big swing. Shotgun production remained relatively steady, only dropping 1.2 percent.

Firearms Production ATF

Editor’s Comment: Since these are production numbers, not sales figures, it may be premature to say that American shooters are spending a lot less money on rifles, but we know that sales of AR-type “black rifles” are down significantly. There was a rush of AR “panic buying” after the last presidential election that was not sustained. We are also concerned that fewer young Americans are learning to shoot rifles, while the average age of target rifle shooters continues to climb. We need to expand efforts to get young people involved in rifle shooting and hunting.

Permalink News No Comments »
February 22nd, 2011

U.S. Gun Production Rises to 5.4 Million Firearms in 2009

According to the latest Firearm Manufacturing and Export Report from the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF), U.S. firearm manufacturers produced more than 5.4 million firearms in 2009. That’s a big increase compared to the start of the decade in 2001, when less than 3,000,000 firearms were manufactured by U.S. companies. In recent years, production of both handguns and long guns has grown significantly, as show in the graph below, prepared by the National Shooting Sports Foundation (NSSF) based on ATF records from 1984-2009.

Firearms production chart

The ATF data (from 1984-2009) reveals some interesting trends:

  • Total firearms produced in 2009 topped 5.4 million, exceeding the previous high total in 1994.
  • Over 3,000,000 long guns were produced in 2009, the highest quantity in the past 25 years.
  • The total number of firearms sold in 2009 works out to one gun for every 57 citizens, based on the 2009 U.S. population of 305,529,237.
  • After a decade-long decline, handgun production rose dramatically from 2004-2009. If trends continue, in a few more years, pistol sales could out-number long gun sales.

NSSF research has updated its 14-page Industry Intelligence Report, titled Firearms Production in the United States, with the most recent data on U.S. production of pistols, revolvers, rifles and shotguns. Additional updated data found in this report include: Annual Survey of Manufacturers figures and U.S. International Trade Commission firearm import and export figures. The report is available for free to NSSF members by logging into the members section of the NSSF website, clicking “NSSF Industry Research” and then clicking “Industry Intelligence Reports.” For more information, log on to www.nssf.org.

Permalink News No Comments »
December 22nd, 2009

Firearm Sales Charted by Region — Southeastern and Mountain States Lead Rifle Purchases

NSGA firearms reportThe National Sporting Goods Association (NSGA) has issued an interesting report charting gun sales by region. Southerners like handguns, and those in the Great Lakes states purchase the most shotguns by far. In 2008, southern Atlantic states led per capita in handgun purchases and also accounted for 31.4 % of all handguns bought in the United States. East north central states led per capita in shotgun purchases and accounted for 33.4 % of shotguns sold.

The Mountain states led per capita in rifle purchases and accounted for 10.7 percent of rifles sold. But the South Atlantic states’ residents buy the most rifles overall — 22% of the nationwide total. It is interesting that the Pacific states (California, Oregon, Washington) encompass 14.7% of the U.S. population, but that region accounts for only 10% of rifles and shotguns sold. On the other hand, Pacific states’ residents buy 14.2% of all handguns, the second highest figure among regions. Maybe all those crazy gun control laws in California haven’t made things any safer, and people feel the need to arm themselves.

Download Full Report on Firearm Sales by Region (PDF File)

Permalink News 1 Comment »