This illustration shows headspace measurement for the popular .308 Winchester cartridge, which headspaces on the shoulder. Image copyright 2015 Ultimate Reloader.
In this Brownells Tech Tip Video, Brownells gun tech Steve Ostrem explains what headspace is and why it’s one of the most critical measurements for nearly all firearms. Even if you’re an experienced rifle shooter, it’s worth watching this video to refresh your understanding of headspace measurements, and the correct use of “GO” and “NO-GO” gauges.
Headspace Definition
In firearms, headspace is the distance measured from the part of the chamber that stops forward motion of the cartridge (the datum reference) to the face of the bolt. Different cartridges have their datum lines in different positions in relation to the cartridge. For example, 5.56x45mm NATO ammunition headspaces off the shoulder of the cartridge, whereas .303 British headspaces off the forward rim of the cartridge. If the headspace is too short, ammunition that is in specification may not chamber correctly. If headspace is too large, the ammunition may not fit as intended or designed and the cartridge case may rupture, possibly damaging the firearm and injuring the shooter. (Source: Wikipedia)
Problems Caused by Too Much Headspace
Excessive headspace issues can include: light primer strikes, failure to fire, bulged/blown cases, case separations, split shoulders, or unseated primers after firing. Case ruptures caused by excessive headspace can lead to catastrophic failures causing serious injury. That is why headspace is such an important measurement.
Problems Cause by Too Little Headspace
Insufficent (or excessively tight) headspace can prevent the firearm from going into battery, resulting in failure to fire or deformation of the cartridge case. Various feeding and functioning problems can be caused by cases with too little headspace, even if a round can be chambered (with effort).
Headspace Gauges
Headspace is measured with a set of two headspace gauges: a “Go” gauge, and a “No-Go” gauge. Headspace gauges resemble the cartridges for the chambers they are designed to headspace, and are typically made of heat-treated tool steel. Both a “Go” and a “No-Go” gauge are required for a gunsmith to headspace a firearm properly. A third gauge, the “Field” gauge, is used (as the name implies) in the field to indicate the absolute maximum safe headspace. This gauge is used because, over time, the bolt and receiver will wear, the bolt and lugs compress, and the receiver may stretch, all causing the headspace to gradually increase from the “factory specs” measured by the “Go” and “No-Go” gauges. A bolt that closes on “No-Go” but not on “Field” is close to being unsafe to fire, and may malfunction on cartridges that are slightly out of spec. (Source: Wikipedia)
You need to understand Headspace Gauges and how to use them. There are “Go”, “No-Go”, and “Field” gauges. The “Field” is actually the longest. Brownells explains: “The GO gauge corresponds to the SAAMI minimum chamber length, while the FIELD gauge usually matches the maximum chamber depth, or slightly less. NO-GO gauges are an intermediate length between minimum and maximum, that, technically, is a voluntary dimension. A firearm that closes on a NO-GO gauge and does not close on a FIELD gauge may not give good accuracy and may have very short cartridge case life [.]”
Probably the most popular centerfire rifle round in the Western Hemisphere is the .223 Remington and its metric match, the 5.56x45mm. Though many folks use “.223 Rem” and “5.56×45″ interchangeably, there are some meaningful differences in specifications for the original .223 Rem and the 5.56x45mm cartridge, as adopted by the U.S. military and NATO armies. The default chamber throats are slightly different and the .223 Rem is rated at 55,000 PSI vs. 62,366 PSI for the 5.56x45mm.*
.223 Rem vs 5.56x45mm — Key Differences
There is a truly outstanding, very thorough article on the subject, published by LuckyGunner.com.** This involved extensive testing, with pressure monitors, of 5.56x45mm ammo in .223 Rem chambers. Those tests revealed the peak pressures. Here is one of the ammo test charts:
NOTE: “The observed chamber pressure for Federal XM855 5.56mm ammunition in a .223 Rem chamber exceeded .223 maximum pressures, but not by a massive amount. The ninth shot (the red line) was an underpowered cartridge which exhibited significantly lower velocity and pressure than the other rounds, so it was excluded from the average velocity and pressure numbers for this chamber.”
And if you’re curious, LuckyGunner also fired .223 Rem ammo in a 5.56x45mm NATO-chambered AR15 rifle. As you would expect, the peak pressures were significantly lower, but the .223 Rem ammo still cycled the semi-auto AR-platform rifle perfectly well:
UltimateReloader.com Explains .223 Rem vs. 5.56x45mm
To explain the key differences between the .223 Rem and 5.56x45mm cartridges our friend Gavin Gear of UltimateReloader.com has created a very thorough 12-minute video. This covers the cartridge specifications and explains key considerations for hand-loaders. Gavin also addresses the oft-asked question “Can I shoot 5.56x45mm ammo in my .223 Rem chamber?” Gavin’s video is definitely worth watching. In fact, this is one of the most popular videos Gavin has ever created — it has been watched nearly 4.5 million times on YouTube.
What Exactly Is the 5.56x45mm NATO Cartridge?
The 5.56×45mm NATO is a rimless bottle-necked intermediate cartridge family standardized by NATO with development work by FN Herstal. It consists of the SS109, SS110, and SS111 cartridges. Under STANAG 4172, it is a standard cartridge for NATO forces as well as many non-NATO countries.
Bullet diameter: 5.70 mm (0.224 in)
Maximum pressure (EPVAT): 430.00 MPa (62,366 psi)
Maximum pressure (SCATP 5.56): 380.00 MPa (55,114 psi)
Case length: 44.70 mm (1.760 in)
Rifling twist: 178 mm or 229 mm (1 in 7 in)
Parent case: .223 Remington (M193)
Ammo-Maker Federal Premium Compares .223 Rem and 5.56x45mm
Here is a video from ammo-maker Federal Premium explaining the difference between .223 Remington and 5.56x45mm NATO. Federal states that you may experience excessive pressures when firing a 5.56x45mm in a standard .223 Remington chamber:
One leading gunwriter has addressed the question of shooting 5.56x45mm ammo in .223 Rem chambers. He advocates caution (for more info, SEE pressure tests by LuckyGunner.com):
“I have received a slew of questions — many from first time AR-type rifle buyers — about the .223 Rem and the 5.56×45 mm NATO cartridges. Can I shoot 5.56×45 mm NATO in my .223 and vice-versa? Are these the same cartridge?
Externally, the two cartridge cases are identical. The main differences are that 5.56×45 mm NATO operates at a higher chamber pressure (about 60,000 PSI versus 55,000 PSI on the .223 Rem.) and the 5.56’s chamber is slightly larger than that of the .223 Rem. Also, the throat or leade is longer in the 5.56×45 mm chamber. What does this mean? You should not shoot 5.56×45 mm NATO out of a rifle that is chambered in .223 Rem [with a standard short throat]. And be aware that some .223 Rem ammunition will not reliably cycle through some AR-style .223 Rem rifles, but it usually does. As a matter of fact, I have not encountered any difficulty with current .223 Rem. loads cycling through a 5.56 mm AR-style rifle.” — Mark Keefe, Editor, American Rifleman
* According to the official NATO proofing guidelines, the 5.56×45mm NATO case can handle up to 430.0 MPa (62,366 psi) piezo service pressure. The U.S. SAAMI lists Maximum Average Pressure (MAP) for the .223 Remington cartridge as 55,000 psi (379.2 MPa) piezo pressure with deviation of up to 58,000 psi (399.9 MPa). The chamber for military 5.56×45mm NATO has a longer throat prior to the bullet contacting the rifling which results in lower pressures when firing 5.56×45mm NATO ammunition. If 5.56×45mm NATO is used in rifles chambered for .223 Remington the bullet will be engraving the rifling when chambered. which can increase pressures past SAAMI Max levels. NOTE: The C.I.P. standards for the C.I.P. civilian .223 Remington chamber are much closer to the military 5.56×45mm NATO chamber.
** The full-length LuckyGunner article is well worth reading. It even provides specifications for a number of .223 Rem reamer types, and compares the original .223 Rem, the 5.56x45mm NATO, and the modern .223 Wylde chamberings.
This illustration shows headspace measurement for the popular .308 Winchester cartridge, which headspaces on the shoulder. Image copyright 2015 Ultimate Reloader.
In this Brownells Tech Tip Video, Brownells gun tech Steve Ostrem explains what headspace is and why it’s one of the most critical measurements for nearly all firearms. Even if you’re an experienced rifle shooter, it’s worth watching this video to refresh your understanding of headspace measurements, and the correct use of “GO” and “NO-GO” gauges.
Headspace Definition
In firearms, headspace is the distance measured from the part of the chamber that stops forward motion of the cartridge (the datum reference) to the face of the bolt. Different cartridges have their datum lines in different positions in relation to the cartridge. For example, 5.56x45mm NATO ammunition headspaces off the shoulder of the cartridge, whereas .303 British headspaces off the forward rim of the cartridge. If the headspace is too short, ammunition that is in specification may not chamber correctly. If headspace is too large, the ammunition may not fit as intended or designed and the cartridge case may rupture, possibly damaging the firearm and injuring the shooter. (Source: Wikipedia)
Problems Caused by Too Much Headspace
Excessive headspace issues can include: light primer strikes, failure to fire, bulged/blown cases, case separations, split shoulders, or unseated primers after firing. Case ruptures caused by excessive headspace can lead to catastrophic failures causing serious injury. That is why headspace is such an important measurement.
Problems Cause by Too Little Headspace
Insufficent (or excessively tight) headspace can prevent the firearm from going into battery, resulting in failure to fire or deformation of the cartridge case. Various feeding and functioning problems can be caused by cases with too little headspace, even if a round can be chambered (with effort).
Headspace Gauges
Headspace is measured with a set of two headspace gauges: a “Go” gauge, and a “No-Go” gauge. Headspace gauges resemble the cartridges for the chambers they are designed to headspace, and are typically made of heat-treated tool steel. Both a “Go” and a “No-Go” gauge are required for a gunsmith to headspace a firearm properly. A third gauge, the “Field” gauge, is used (as the name implies) in the field to indicate the absolute maximum safe headspace. This gauge is used because, over time, the bolt and receiver will wear, the bolt and lugs compress, and the receiver may stretch, all causing the headspace to gradually increase from the “factory specs” measured by the “Go” and “No-Go” gauges. A bolt that closes on “No-Go” but not on “Field” is close to being unsafe to fire, and may malfunction on cartridges that are slightly out of spec. (Source: Wikipedia)
You need to understand Headspace Gauges and how to use them. There are “Go”, “No-Go”, and “Field” gauges. The “Field” is actually the longest. Brownells explains: “The GO gauge corresponds to the SAAMI minimum chamber length, while the FIELD gauge usually matches the maximum chamber depth, or slightly less. NO-GO gauges are an intermediate length between minimum and maximum, that, technically, is a voluntary dimension. A firearm that closes on a NO-GO gauge and does not close on a FIELD gauge may not give good accuracy and may have very short cartridge case life [.]”
If you asked a group of shooters to explain the difference between CUP and PSI, the majority would probably not be able to give a precise answer. But, for safety reasons, it’s very important that all hand-loaders understand these important terms and how they express cartridge pressures.
The ANSI / SAAMI group, short for “American National Standard Institute” and “Sporting Arms and Ammunition Manufacturers’ Institute”, have made available some time back the voluntary industry performance standards for pressure and velocity of centerfire rifle sporting ammunition for the use of commercial manufacturers. [These standards for] individual cartridges [include] the velocity on the basis of the nominal mean velocity from each, the maximum average pressure (MAP) for each, and cartridge and chamber drawings with dimensions included. The cartridge drawings can be seen by searching the internet and using the phrase ‘308 SAAMI’ will get you the .308 Winchester in PDF form. What I really wanted to discuss today was the differences between the two accepted methods of obtaining pressure listings. The Pounds per Square Inch (PSI) and the older Copper Units of Pressure (CUP) version can both be found in the PDF pamphlet.
CUP Pressure Measurement
The CUP system uses a copper crush cylinder which is compressed by a piston fitted to a piston hole into the chamber of the test barrel. Pressure generated by the burning propellant causes the piston to move and compress the copper cylinder. This will give it a specific measurable size that can be compared to a set standard. At right is a photo of a case that was used in this method and you can see the ring left by the piston hole.
PSI Pressure Measurement
What the book lists as the preferred method is the PSI (pounds per square inch or, more accurately, pound-force per square inch) version using a piezoelectric transducer system with the transducer flush mounted in the chamber of the test barrel. Pressure developed by the burning propellant pushes on the transducer through the case wall causing it to deflect and make a measurable electric charge.
Q: Is there a standardized correlation or mathematical conversion ratio between CUP and PSI values?
Mahin: As far as I can tell (and anyone else can tell me) … there is no [standard conversion ratio or] correlation between them. An example of this is the .223 Remington cartridge that lists a MAP of 52,000 CUP / 55,000 PSI but a .308 Winchester lists a 52,000 CUP / 62,000 PSI and a 30-30 lists a 38,000 CUP / 42,000 PSI. It leaves me scratching my head also but it is what it is. The two different methods will show up in listed powder data[.]
So the question on most of your minds is what does my favorite pet load give for pressure? The truth is the only way to know for sure is to get the specialized equipment and test your own components but this is going to be way out of reach for the average shooter, myself included. The reality is that as long as you are using printed data and working up from a safe start load within it, you should be under the listed MAP and have no reason for concern. Being specific in your components and going to the load data representing the bullet from a specific cartridge will help get you safe accuracy. [With a .308 Winchester] if you are to use the 1% rule and work up [from a starting load] in 0.4 grain increments, you should be able to find an accuracy load that will suit your needs without seeing pressure signs doing it. This is a key to component longevity and is the same thing we advise [via our customer service lines] every day. Till next time, be safe and enjoy your shooting.
Probably the most popular centerfire rifle round in the Western Hemisphere is the .223 Remington and its metric match, the 5.56x45mm. Though many folks use “.223 Rem” and “5.56×45″ interchangeably, there are some meaningful differences in specifications for the original .223 Rem and the 5.56x45mm cartridge, as adopted by the U.S. military and NATO armies. The default chamber throats are slightly different and the .223 Rem is rated at 55,000 PSI vs. 62,366 PSI for the 5.56x45mm.*
.223 Rem vs 5.56x45mm — Key Differences
There is a truly outstanding, very thorough article on the subject, published by LuckyGunner.com.** This involved extensive testing, with pressure monitors, of 5.56x45mm ammo in .223 Rem chambers. Those tests revealed the peak pressures. Here is one of the ammo test charts:
NOTE: “The observed chamber pressure for Federal XM855 5.56mm ammunition in a .223 Rem chamber exceeded .223 maximum pressures, but not by a massive amount. The ninth shot (the red line) was an underpowered cartridge which exhibited significantly lower velocity and pressure than the other rounds, so it was excluded from the average velocity and pressure numbers for this chamber.”
And if you’re curious, LuckyGunner also fired .223 Rem ammo in a 5.56x45mm NATO-chambered AR15 rifle. As you would expect, the peak pressures were significantly lower, but the .223 Rem ammo still cycled the semi-auto AR-platform rifle perfectly well:
UltimateReloader.com Explains .223 Rem vs. 5.56x45mm
To explain the key differences between the .223 Rem and 5.56x45mm cartridges our friend Gavin Gear of UltimateReloader.com has created a very thorough 12-minute video. This covers the cartridge specifications and explains key considerations for hand-loaders. Gavin also addresses the oft-asked question “Can I shoot 5.56x45mm ammo in my .223 Rem chamber?” Gavin’s video is definitely worth watching. In fact, this is one of the most popular videos Gavin has ever created — it has been watched nearly 4.5 million times on YouTube.
What Exactly Is the 5.56x45mm NATO Cartridge?
The 5.56×45mm NATO is a rimless bottle-necked intermediate cartridge family standardized by NATO with development work by FN Herstal. It consists of the SS109, SS110, and SS111 cartridges. Under STANAG 4172, it is a standard cartridge for NATO forces as well as many non-NATO countries.
Bullet diameter: 5.70 mm (0.224 in)
Maximum pressure (EPVAT): 430.00 MPa (62,366 psi)
Maximum pressure (SCATP 5.56): 380.00 MPa (55,114 psi)
Case length: 44.70 mm (1.760 in)
Rifling twist: 178 mm or 229 mm (1 in 7 in)
Parent case: .223 Remington (M193)
Ammo-Maker Federal Premium Compares .223 Rem and 5.56x45mm
Here is a video from ammo-maker Federal Premium explaining the difference between .223 Remington and 5.56x45mm NATO. Federal states that you may experience excessive pressures when firing a 5.56x45mm in a standard .223 Remington chamber:
One leading gunwriter has addressed the question of shooting 5.56x45mm ammo in .223 Rem chambers. He advocates caution (for more info, SEE pressure tests by LuckyGunner.com):
“I have received a slew of questions — many from first time AR-type rifle buyers — about the .223 Rem and the 5.56×45 mm NATO cartridges. Can I shoot 5.56×45 mm NATO in my .223 and vice-versa? Are these the same cartridge?
Externally, the two cartridge cases are identical. The main differences are that 5.56×45 mm NATO operates at a higher chamber pressure (about 60,000 PSI versus 55,000 PSI on the .223 Rem.) and the 5.56’s chamber is slightly larger than that of the .223 Rem. Also, the throat or leade is longer in the 5.56×45 mm chamber. What does this mean? You should not shoot 5.56×45 mm NATO out of a rifle that is chambered in .223 Rem [with a standard short throat]. And be aware that some .223 Rem ammunition will not reliably cycle through some AR-style .223 Rem rifles, but it usually does. As a matter of fact, I have not encountered any difficulty with current .223 Rem. loads cycling through a 5.56 mm AR-style rifle.” — Mark Keefe, Editor, American Rifleman
* According to the official NATO proofing guidelines, the 5.56×45mm NATO case can handle up to 430.0 MPa (62,366 psi) piezo service pressure. The U.S. SAAMI lists Maximum Average Pressure (MAP) for the .223 Remington cartridge as 55,000 psi (379.2 MPa) piezo pressure with deviation of up to 58,000 psi (399.9 MPa). The chamber for military 5.56×45mm NATO has a longer throat prior to the bullet contacting the rifling which results in lower pressures when firing 5.56×45mm NATO ammunition. If 5.56×45mm NATO is used in rifles chambered for .223 Remington the bullet will be engraving the rifling when chambered. which can increase pressures past SAAMI Max levels. NOTE: The C.I.P. standards for the C.I.P. civilian .223 Remington chamber are much closer to the military 5.56×45mm NATO chamber.
** The full-length LuckyGunner article is well worth reading. It even provides specifications for a number of .223 Rem reamer types, and compares the original .223 Rem, the 5.56x45mm NATO, and the modern .223 Wylde chamberings.
The Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI), has released two new online reference tables. These resources clarify the interchangeability of certain ammunition in a specified firearm chamber, and identify the names of equivalent and historical cartridges.
SAMMI states: “These documents are important for firearm safety because they … identify what ammunition can be safely shot in firearms, whether it is an alternate cartridge in a specified firearm chamber or a known equivalent historical name for a cartridge.”
“These important documents … provide guidance to both industry professionals and the firearm-owning community. They emphasize important safety and technical information regarding the proper matching of ammunition and firearms, and what precautions must be taken”, stated Joe Bartozzi, SAAMI President/CEO.
New Resource Content (Click Charts to view PDF Files)
Generally Accepted Firearms and Ammunition Interchangeability — This document lists generally accepted alternate firearm/ammunition combinations which will generally allow for the safe firing of an alternate cartridge in a specified firearm chamber. There is also information on shotshell interchangeability and commercial vs. military standards.
NOTE: Beyond historical cartridge names that are in common use, there are a very few firearm/ammunition combinations which will generally allow for the safe firing of an alternate cartridge in a specified firearm chamber. CLICK HERE for SAAMI’s listing of those cartridges/chambers.
This illustration shows headspace measurement for the popular .308 Winchester cartridge, which headspaces on the shoulder. Image copyright 2015 Ultimate Reloader.
In this Brownells Tech Tip Video, Brownells gun tech Steve Ostrem explains what headspace is and why it’s one of the most critical measurements for nearly all firearms. Even if you’re an experienced rifle shooter, it’s worth watching this video to refresh your understanding of headspace measurements, and the correct use of “GO” and “NO-GO” gauges.
Headspace Definition
In firearms, headspace is the distance measured from the part of the chamber that stops forward motion of the cartridge (the datum reference) to the face of the bolt. Different cartridges have their datum lines in different positions in relation to the cartridge. For example, 5.56x45mm NATO ammunition headspaces off the shoulder of the cartridge, whereas .303 British headspaces off the forward rim of the cartridge. If the headspace is too short, ammunition that is in specification may not chamber correctly. If headspace is too large, the ammunition may not fit as intended or designed and the cartridge case may rupture, possibly damaging the firearm and injuring the shooter. (Source: Wikipedia)
Problems Caused by Too Much Headspace
Excessive headspace issues can include: light primer strikes, failure to fire, bulged/blown cases, case separations, split shoulders, or unseated primers after firing. Case ruptures caused by excessive headspace can lead to catastrophic failures causing serious injury. That is why headspace is such an important measurement.
Problems Cause by Too Little Headspace
Insufficent (or excessively tight) headspace can prevent the firearm from going into battery, resulting in failure to fire or deformation of the cartridge case. Various feeding and functioning problems can be caused by cases with too little headspace, even if a round can be chambered (with effort).
Headspace Gauges
Headspace is measured with a set of two headspace gauges: a “Go” gauge, and a “No-Go” gauge. Headspace gauges resemble the cartridges for the chambers they are designed to headspace, and are typically made of heat-treated tool steel. Both a “Go” and a “No-Go” gauge are required for a gunsmith to headspace a firearm properly. A third gauge, the “Field” gauge, is used (as the name implies) in the field to indicate the absolute maximum safe headspace. This gauge is used because, over time, the bolt and receiver will wear, the bolt and lugs compress, and the receiver may stretch, all causing the headspace to gradually increase from the “factory specs” measured by the “Go” and “No-Go” gauges. A bolt that closes on “No-Go” but not on “Field” is close to being unsafe to fire, and may malfunction on cartridges that are slightly out of spec. (Source: Wikipedia)
To learn more, read Brownell’s article Headspace Gauges and How to Use Them. Among other things, this explains the relative lengths of “Go”, “No-Go”, and “Field” gauges. The “Field” is actually the longest: “The GO gauge corresponds to the SAAMI minimum chamber length, while the FIELD gauge usually matches the maximum chamber depth, or slightly less. NO-GO gauges are an intermediate length between minimum and maximum, that, technically, is a voluntary dimension. A firearm that closes on a NO-GO gauge and does not close on a FIELD gauge may not give good accuracy and may have very short cartridge case life from the ammunition re-loader’s standpoint.”
The Sporting Arms and Ammunition Manufacturers’ Institute, Inc., (SAAMI), has announced the acceptance of three (3) new cartridges for SAAMI standardization: 1) 277 SIG FURY; 2) 6.5 Weatherby Rebated Precision Magnum (WBY RPM); 3) 6.8 Western. While the 277 SIG FURY was developed originally for the U.S. Military, it should serve well for hunters, as will the new 6.5 Weatherby RPM and 6.8 Western. SAAMI has standardized the dimensions, max pressures, and load specs for all these three new cartridges.
277 SIG FURY from SIG Sauer
Developed by SIG SAUER for the U.S. Military, the 277 SIG FURY boasts a SAAMI maximum average pressure of 80,000 psi, driving a 135-grain bullet to 3,000+ fps. That 80K PSI pressure is WAY higher than almost all other cartridge types. To achieve these high pressures, the 277 FURY uses a hybrid case with a brass body and harder alloy metal case head. This design allows the cartridge to run very high pressures. Dan Horner of SIG Sauer told us: “When the handloaders get hold of this brass, it will be a game-changer for sure”. We envision this cartridge could be necked down to 6.5 mm and it would dramatically out-perform the 6.5 Creedmoor. And yes the official name of the cartridge is all caps “277 SIG FURY”.
Developed by Weatherby, the 6.5 Weatherby Rebated Precision Magnum (WBY RPM) was introduced with a maximum average pressure of 65,000 psi, with a 140-grain bullet traveling at a velocity of 3,075 fps. The 6.5 WBY RPM offers signficantly higher velocities that most other 6.5mm cartridges, including the 6.5-284 and .265 Win Mag. SEE 6.5 Cartridge Comparison Table
Developed by Olin Winchester, the 6.8 Western was introduced with a maximum average pressure of 65,000 psi, with a .277-caliber 175-grain bullet traveling at a velocity of 2,840 fps. A shorter variant of the Winchester Short Magnum (WSM) family, the new cartridge appears to be about .090″ shorter than the .270 WSM. It has the same 35-degree shoulder angle as the .270 WSM.
NOAA photo of flooding after Hurricane Floyd in 1999. The Colt Python Revolver once belonged to Elvis Presley (Rock Island Auction).
This past week, Tropical Storm Isaias has hammered the East Coast of the USA. The BBC reported: “From North Carolina up to New York, Isaias left more than 3.4 million residents without power. It spawned tornadoes, uprooted trees, damaged homes and caused floods and fires.” This article explains what to do if you have experienced flooding.
Firearms owners who have seen their guns and stored ammunition submerged by flood waters in storm-wracked areas are probably wondering if their firearms and ammunition can be salvaged and safely used. To answer these questions, the NSSF and the Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI®) created two documents outlining the proper response to submersion of guns and ammo. If you’ve got wet guns and/or ammo, download these two PDF files and read them carefully.
The SAAMI document “Guidance on Firearms That Have Been Submerged or Exposed to Extensive Amounts of Water” points out two major concerns about firearms that have been exposed to water: parts susceptible to moisture and rust damage such as metal parts, wood stocks and grips, and optics; and, secondly, infiltration of the action, barrel and safety systems by grit, silt and other foreign debris.
#1 Always unload firearms before beginning any treatment process.
It’s important to limit moisture and corrosion damage to the component parts of the firearm. This can be accomplished by disassembling the component parts and using up to two coats of a moisture-displacing lubricant such as Hoppes #9 MDL or WD-40 to clean and stabilize the parts while, importantly, following the product’s directions so as not to damage, for instance, plastic or synthetic parts. Another tip is to allow wood stocks and grips to air-dry and not be force dried by exposure to heat.
The document emphasizes that once the firearm has been thoroughly dried, consideration must be given to having the firearm inspected and serviced by the manufacturer, an authorized service center, or a qualified gunsmith before putting the firearm back in service.
Dealing with Ammunition That Was Submerged
Bottom Line, if your ammo has been submerged — DON’T USE IT. SAAMI explains why…
To help firearms owners determine what to do with ammunition that has been affected by water and moisture, SAAMI offers another helpful document, “Guidance on Ammunition That Has Been Submerged in Water.” This document covers differences in moisture resistance between centerfire, rimfire and shotshell ammunition, and potential hazards associated with “drying out” cartridges, including possible deterioration and damage to cartridges due to drying methods.
Another serious hazard that could result from using compromised ammunition is the potential for a bore obstruction due to partial ignition of either the priming compound or the propellant powder charge, or both. Firing a subsequent round through an obstructed barrel can result in bodily injury, death and property damage.
SAAMI provides the following cautionary conclusion: “It would be impossible to ascertain for certain the extent of the deteriorating affect, if any, the water may have had on each individual cartridge. Therefore, the safe answer is that no attempt be made to salvage or use submerged ammunition. The ammunition should be disposed of in a safe and responsible manner. Contact your local law enforcement agency for disposal instructions in your area.”
Peterson Cartridge Company (“Peterson”) has released a lengthy, authoritative guide to the 22 Creedmoor cartridge, a popular wildcat based on the 6.5 Creedmoor or 6mm Creedmoor necked down to .224 caliber. We think the 22 Creedmoor would be a great long-range varmint cartridge, similar to the .22-250 Rem, but with a more moder, efficient cartridge design. In addition, some PRS/NRL competitors may turn to the 22 Creedmoor because it has less recoil and is flatter-shooting than the 6mm Creedmoor. In addition, .224-caliber match bullets are typically less expensive than heavier 6mm and 6.5mm projectiles. Less recoil, and less cost — what’s not to like?*
Along with load data, this article has specific sections dedicated to: Primers, Rifling Twist Rates, and Reloading Supplies. If you are considering building a .22 Creedmoor, we recommend you download the full Peterson .22 Creedmoor article, which is available in PDF format.
Peterson states, “Since its inception in 2007… the 6.5 Creedmoor has seen some pretty meteoric growth in popularity. That growth continues as of this writing, as the cartridge has now gone mainstream with hunters and shooters alike. As the popularity of the 6.5 Creedmoor has increased, so has the number of wildcat cartridges based off of it. Some of those popular wildcat cartridges are the 6mm Creedmoor, the .25 Creedmoor, and now the .22 Creedmoor. This data sheet will cover the .22 Creedmoor.
To help our customers, and anyone else who shoots .22 Creedmoor, we decided to create this Data Sheet and distribute it. [In this LOAD DATA Document] you will find four (4) common bullets, and four (4) common rifle powders used when handloading the .22 Creedmoor cartridge. We then took the different bullet and powder combinations and loaded them up to the SAAMI Maximum Average Pressure (MAP) for the 6.5 Creedmoor and 6mm Creedmoor cartridges, which is 62,000 PSI. [O]ur goal was to provide a wide spectrum of bullet weights and the powders used with them.
All of the following data was gathered by our ballistician in our indoor ballistics lab located in our factory in Pennsylvania. Although we were able to gather pressure and velocity data in our lab, we have NOT tested these loads for accuracy. Again, these loads are just designed to give shooters information regarding what velocity, a given bullet and powder charge combination, will produce the SAAMI Maximum Average Pressure (MAP) of 62,000 psi.”
Sample .22 Creedmoor LOAD DATA
IMPORTANT — Pressures can vary significantly with different Cartridge Overall Lengths (COAL). In addition, ANY change to ANY load components — primers, bullets, brass, powder — can affect pressure. Always load conservatively. In addition, because of variances in bore dimensions, some barrels may show higher pressures than others. Again, always start with conservative loads, well below MAX pressures.
*Actually there IS a potential downside — reduced barrel life. We expect that a .22 Creedmoor running hot varmint loads would experience shorter useful barrel life compared to a 6.5 Creedmoor. This is based on what we’ve observed with .22-250 and .22-250 Ackley barrels compared to our 6.5 CM barrels.
Headspace Gauges
CUP Pressure Measurement
Headspace Gauges
