March 12th, 2020

Fact vs. Fiction — .223 Rem vs. 5.56x45mm NATO Cartridges

.223 Rem Remington 5.56 SAAMI CIP 5.56x45 5.56x45mm NATO cartridge ammo pressure test luckygunner ultimatereloader Gavin Gear

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:

.223 Rem Remington 5.56 SAAMI CIP 5.56x45 5.56x45mm NATO cartridge ammo pressure test luckygunner ultimatereloader Gavin Gear

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:

.223 Rem Remington 5.56 SAAMI CIP 5.56x45 5.56x45mm NATO cartridge ammo pressure test luckygunner ultimatereloader Gavin Gear

READ FULL LuckyGunner .223 Rem vs. 5.56x45mm ARTICLE »

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 over 300,000 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. 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.

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March 12th, 2020

TECH Tip — When and How to Clean Your Reloading Dies

Hornady Die cleaning

After purchasing a new set of dies from Forster, Hornady, Redding, or Whidden Gunworks, you’ll want to disassemble the dies, inspect then, and then remove the internal grease and/or waxy coatings placed on the dies by the manufacturer. Here are two video that show how to de-grease and clean dies as they come “out of the box” from the manufacturer. In the first video, from Creedmoor Sports, Bill Gravatt (now President of Capstone Precision Group) shows various methods for cleaning dies both when new and after they have accumulated carbon and lube after use. This video is definitely worth watching. In the second video, a Hornady technician shows the method for degreasing dies before first use. A convenient aerosol spray cleaner is used in the video. You an also use a liquid solvent with soft nylon brush, and cotton patches. NOTE: After cleaning you may want to apply a light grease to the external threads of your dies.

Creedmoor Sports Die Cleaning Video with Bill Gravatt

Hornady Video Showing Aerosol Cleaner

Clean Your Sizing Dies and Body Dies Regularly
These same techniques work for cleaning dies after they have been used for reloading. Many otherwise smart hand-loaders forget to clean the inside of their dies, allowing old case lube, gunk, carbon residue, and other contaminants to build up inside the die. You should clean your dies fairly often, particularly if you do not tumble or ultrasound your cases between loadings. It is most important to keep full-length sizing and body dies clean. These dies accumulate lube and carbon residue quickly.

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March 12th, 2020

Minute of Angle (MOA) Explained by Informative Video

one minute of angle

This popular video, viewed nearly 1.9 million times on YouTube, provides a clear explanation of Minute of Angle (MOA) and how that angular measurement is used. Among novice shooters, there is much confusion over this term. In this NSSF Video, Ryan Cleckner, a former Sniper Instructor for the 1st Ranger Battalion, defines the term, “Minute of Angle” (MOA) and explains how you can adjust for windage and elevation using 1/4 or 1/8 MOA clicks on your scope. This allows you to sight-in precisely and compensate for bullet drop at various distances.

For starters, Ryan explains that, when talking about angular degrees, a “minute” is simply 1/60th. So a “Minute of Angle” is simply 1/60th of one degree of a central angle, measured either up and down (for elevation) or side to side (for windage). At 100 yards, 1 MOA equals 1.047″ on the target. This is often rounded to one inch for simplicity. Say, for example, you click up 1 MOA. That is roughly 1 inch at 100 yards, or roughly 4 inches at 400 yards, since the target area measured by 1 MOA increases in linear fashion with the distance.

Story sourced by Edlongrange.
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