COMMERCIAL vs. MILITARY BRASS WHAT’S THE DIFFERENCE?
Certain firearm platforms are able to accommodate commercial cartridge cases as well as military cartridge cases interchangeably. This is especially so for reloaders who are in a position to slightly alter or adjust certain elements or components in order to do so. Comparative examples may include the 5.56 x 45 mm (5.56 NATO) vs. the .223 Remington; or the 7.62 x 51 mm (7.62 NATO) vs. the .308 Winchester.
In most instances, the external dimensions are the same (or approximately the same) between compatible (commercial vs. military) cartridge cases. This is because one version is often the ‘parent’ case to the other. Either the commercial market offered a firearm that the military wanted to employ, or the military used a firearm that was commercially viable for the public marketplace.
In general, the primary difference between commercial and military cartridge cases is the thickness of the brass itself. Commercial brass is typically thinner and, therefore, possesses a greater volume within its powder chamber. It is also more susceptible to cracks, ruptures, or other material breakdowns. Military brass, on the other hand, is made thicker in order to hold up better under extreme conditions. Perhaps the most obvious of these conditions is the abuse a cartridge case endures running through an automatic weapon. For reloaders, adjustments need to be made in the powder load for the different capacities (volume) of the powder chambers. Always consult the Reloader’s Guides for the recommended powder loads.
Another difference between commercial and military brass is the primer crimp that exists on the military cartridge case. Again, this feature in design is related to the extreme rigor the casing is expected to endure. For reloaders, this crimp must be removed, creating an additional step. Top Brass reams the primer pocket for all of its reconditioned military cartridge cases.
The principle advantage for using military cartridge cases over commercial cartridge cases is the added thickness of the brass. When a firearm is discharged, the brass casing expands and contracts. In doing so, the brass is exposed to extreme (explosive) stress. Obviously, thicker walls on the cartridge will better manage material fatigue over the life of the cartridge. For active reloaders, the lifespan of a single cartridge may extend 10 to 15 fire rotations.
In summary, military brass is often preferred over commercial brass due to its material robustness and ability to last over a greater number of reloads.
- Battalion Commerce Collaborator
NEW BRASS vs. ‘ONCE-FIRED’ BRASS WHAT’S THE DIFFERENCE?
Top Brass specializes in the remanufacture and reconditioning of ‘Once-Fired’ brass cartridge cases. The differences between our cartridge case and a newly manufactured one are both small and large – small when considering the actual specifications associated with the final product, and large when compared to the price.
Overall, commercially remanufactured cartridge cases are produced under federally licensed and insured manufacturers. Following strict quality control processes that ensure all SAAMI (Sporting Arms and Ammunition Manufactures Institute) specifications are complied with, finished products include all material and dimensional standards established by SAAMI for safety and functional operation within the appropriate firearm.
Once-Fired: All seasoned reloaders know that the key to purchasing reconditioned brass is to get ‘Once- Fired.’ The simple reasoning is that quality brass cartridge cases have a reusability of 10 to 15 reloads (quasi-benchmark) before they are worn out. ‘Once-Fired’ brass ensures that the brass has not been ‘work-hardened’ or near stress failure over the course of multiple reloadings under unknown conditions. Who knows what level of neglect, misuse, and abuse a cartridge case has been through when picking up brass out at the range? ‘Once-Fired’ brass from a reputable manufacturer guarantees the cartridge case has been discharged through a firearm once in its product life.
Specifications: Bearing in mind that new ammunition is typically mass produced in large quantities – with the dictate to keep within SAAMI specifications – dimensional variations within these SAAMI tolerances will likely exist across each given case. In other words, each round is different (thousandths). Remanufactured / reconditioned cartridge cases, on the other hand, are typically produced in lower volumes. In turn, the quality of tighter tolerances is much more easily managed. Truth be told, reconditioned brass from reputable manufacturers likely have better specs. than those manufactured new.
Fire-Forming: All competitive shooters know, it is the ‘Fire-Forming’ of the cartridge case that creates accuracy. Fire-forming is the process whereby a cartridge case forms to the chamber of the firearm from which it has been previously fired from. The pressure exerted from the discharge expands the brass to fit the contours of the chamber, thus creating improved concentricity of the mouth of the case to the bore, as well as precise headspacing. Therefore, it follows that all precision shooting should use Fire-Formed cartridge cases. That said, what’s the advantage of using new brass?
Price: Reconditioned cartridge cases are substantially less expensive than newly manufactured ones. Discounts range from 30% to 60% off the retail price. In lieu of the above information, why pay the premium for new?
- Top Brass LLC Admin
.308 Winchester vs. 7.62 NATO WHAT’S THE DIFFERENCE?
From an external dimension standpoint, the .308 Winchester cartridge case and the 7.62 NATO (7.62 x 51 mm) are the same thing. In fact, the 7.62 was developed using the general design of the .308 as its ‘parent’ case. The difference between the two, beyond the outside dimensions, is basically two-fold:
- Internal dimensions – brass thickness;
- Barrel chamber length for the different cartridges.
In general, military brass is thicker than commercial brass. This design feature is to accommodate NATO specifications, which include varying chambers specs. across multiple platforms (the thicker brass is better able to stretch and accommodate these chamber variations). Additionally, the case cartridges must withstand the rigors associated with automatic weapons.
Brass Thickness: Because the 7.62 case cartridge has thicker walls, yet has the same external dimension of the .308 case cartridge, it follows that the powder capacity of the 7.62 is lower than the .308. In turn, reloaders should consult their Reloader’s Guide and adjust their powder loads according to the specific calibers of the rifles they will be fired from. All things being the same, the thicker case (smaller capacity) will generate a higher pressure. Too high of pressure may result in a primer leak and other pressure problems.
Chamber Design: Perhaps the real difference between the .308 Winchester cartridge case and the 7.62 NATO case is the chambers they are specifically designed for. Typically, military rifles are made with slightly longer chambers (longer headspace). This is to help insure fast, easy feeding and ejection through rapid-fire sequences (i.e. auto-fire). The published difference in this headspace between the two cartridge cases is approximately six-thousandths of an inch – small, yet, significant.
Bearing in mind that the .308 Winchester is specified for a ‘hotter’ powder load than that of the 7.62, firing it in a chamber with the added headspace will stretch the brass much more than the lower powder load 7.62. With a thinner brass wall design, the results may lead to an over-stretching (i.e. case ruptures, etc.).
In summary, the biggest difference between the .308 Winchester cartridge case and the 7.62 NATO cartridge case is with the chambers they are designed for. Manufactured .308 Winchester and 7.62 NATO rounds can safely and effectively be fired in rifles design for .308 calibers, but manufactured 7.62 rounds should be shot only within rifles designated for 7.62 calibers.
- Ryan Gebhardt
.223 Remington vs. 5.56 NATO WHAT’S THE DIFFERENCE?
Case cartridges for the 5.56 NATO (5.56 x 45 mm) and the .223 Remington are very similar. For all practical purposes, the external dimensions are identical, and one can effectively say that there exists no difference between the two. Both are designed to accommodate a .224 inch (5.56 mm) bullet between 40 to 85 grains, and both offer fairly equal performance in range and accuracy.
From an internal standpoint, however, there are some differences to be aware of – most notably, the case capacity. Simply put, the 5.56 case has thicker brass walls to handle higher pressures and, therefore, has less interior volume than the .223 case. This is especially important to reloaders because the powder loads are affected by these different case capacities. Always check your Reloader’s Guide when preparing these cases. There is a difference.
Beyond the interior case capacity, the significant difference between the 5.56 NATO and the .223 Remington case cartridges is found in the barrel chambers in which they are used. Although both rounds will fit into barrel chambers designed for either cartridge, the leade for each is very different.
The leade of a barrel is the area in front of the chamber, but before where the rifling begins. For the .223 Remington, the leade specification (SAAMI) is 0.085 inches. For the 5.56, the leade specification (SAAMI) is 0.162 inches, or, almost double. This difference is notable.
Because standard 5.56 NATO rounds are produced with higher pressure loads, if it’s fired in a rifle designed for a .223 Remington, the shorter leade in the .223 Remington chamber will further increase the pressure – potentially to an unsafe level. Additionally, manufactured 5.56 rounds are made for the longer leade and, therefore, may have the bullet seated differently. If the bullet from a 5.56 makes contact with the rifling in a chamber designed for a .223 Remington prior to being fired, this too can cause unwanted pressure increases.
Conversely -- firing a .223 Remington round through a 5.56 chamber -- is fine, however, the ballistics of the bullet may be affected through a lower velocity. In summary, the 5.56 NATO case cartridge and the .223 Remington case cartridge are interchangeable.
Nevertheless, reloaders need to be aware of the powder loads and bullet seating that will correctly accommodate the chamber of the rounds they’re being prepared for.
- Ryan Gebhardt
Welcome to the New TopBrass.com WebsiteWelcome to the brand new TopBrass online store!
- Ben Skigen