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, 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. Used as a verb, headspace refers to the interference created between this part of the chamber and the feature of the cartridge that achieves the correct positioning. 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)
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 longer 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 (Sporting Arms & Ammunition Manufacturer’s Institute) 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.”
Here are fifteen (15) of the best individual bargains we found for the Black Friday/Cyber Monday Cycle. We shopped dozens of sites and looked for popular, quality items listed at significant savings — over 70% off in some cases. But don’t hesitate, some of these deals expire tonight. Others are good for four days, through Cyber-Monday at 11:59 pm.
Brownells has partnered with Special Operations Wounded Warriors (SOWW), a 501(c)(3) charitable organization, to provide service dogs for Purple Heart recipients of the U.S. Special Operations community during the Cash for K9s event.
Cash for K9s started on Veterans Day (November 11th) and runs through November 17. Brownells shoppers may make donations to support Cash for K9s, with Brownells matching the total of all donations up to $50,000. Brownells will donate a minimum of $25,000 to SOWW and will match up to $50,000.
Customers can donate on the Brownells SOWW page by clicking on the brown buttons below the Cash for K9s image. there are seven (7) buttons, for $1 up to $100 donations. All donations are sent directly to SOWW to help cover all costs associated with training the dogs and pairing them with their new, deserving best friends.
CLICK buttons to go to DONATION Page. Matching Program ends 11/17/2019.
“We are forever thankful for the great support offered to America’s Veterans and members of the Special Operations communities by our partners in charity at Brownells,” said SOWW Board Vice President Joel Pellicci. “Their efforts today to raise funds for our K9 program will help provide these incredible service animals to Warriors in need[.] Brownells’ continued and consistent ability to serve those that serve us is truly helping save lives.”
Brownells just made it easier to get product questions answered, and to find the items you want on the Brownells website at Brownells.com. Customers can now consult live with a Brownells Gun Guru Product Expert. In addition to giving product advice, the Gun Gurus can help customers with account issues, give information about previous orders, and handle most customer concerns.
Starting Monday, September 9, customers can click on the CHAT icon at the top of the website to be connected with a Gun Guru Product Expert.
Pop-Up Gun Guru Chat Window
There is also a floating chat button on the right side of the page (see photo at right). And, after 30 seconds or so a Gun Guru invitation window will pop up. NOTE: We found that if you click on the CHAT icon at the top of the page you must fill in your name and address. However, if you respond to the floating pop-up Chat Window you do NOT have to enter name and email. We think it’s easier to just use the pop-up window.
Gun Guru Product Expert Chat is available on Brownells.com Monday through Friday, 7:30 am until midnight (CT), and on weekends 8:00 am until 5:00 pm (CT).
When you start a chat, a chat window opens with a small photo of the Gun Guru. This person will be either a Brownells Gun Tech (an actual trained gunsmith) or a vetted firearms enthusiast who can offer advice on product categories for which they are most familiar.
“The mission of the Gun Guru Product Experts will be to help educate customers on products and give recommendations, so customers can make informed decisions,” said Ted Somers, Brownells Director of Customer Experience.
Telephone Customer Service is Still Available at 1-800-741-0015
While Brownells Gun Techs will participate in Gun Guru Product Expert chat online, customers with more technical questions can still call 1-800-741-0015 and ask to speak with a Brownells Gun Tech during regular business hours.
Many of the Labor Day Sales have terminated — but don’t fret. We’ve found some Brownells Discount codes that can still save you 10% on your purchases, PLUS entitle you to FREE Shipping. You will want to check out Brownells current Discount Codes. These Codes will qualify you for significant savings plus FREE Shipping on guns, ammo, parts, and reloading components. Use these Codes during check-out and the savings will reduce your net cost. Get up to $20 off on a $200 purchase — that’s a 10% savings. Plus the free shipping/handling could save you another $10-$20 easy. NOTE: Some of these discount codes may expire at any time, so don’t hesitate. If one Code doesn’t work, try another.
Our take on Bore-Store Gun sleeves is simple: They work great, so buy them and use them — for ALL your valuable firearms.
These thick, synthetic-fleece sacks cushion your guns, preventing nicks and scratches. The breathable fabric wicks away moisture, and the fibers are coating with corrosion inhibitors. I personally use Bore-Stores for in-safe storage with all my guns, and I have never had one of my guns rust inside a Bore-Store, even when I lived a stone’s throw from the ocean.
Bore-Stores are offered in a wide range of sizes, so you can find something to fit everything from a Snub-nosed revolver to a 32″-barrelled 50 BMG. Rifle-size Bore Stores can be purchased for $12.00 – $21.00 from Brownells. For long F-Class or tactical rifles, we recommend the 10″x52″ Scoped Shotgun Bag, Brownells item 132-000-003. You can also order direct from the Bore-Store manufacturer, Big Spring Enterprises, www.BoreStores.com. Big Spring will also craft custom sizes on request.
Get Your Guns Out of Foam-lined Cases — They Are Rust Magnets
Just about the worst thing you can do for long-term storage (short of leaving your rifle outside in the rain) is to store firearms in tight, foam-padded cases. The foam in these cases actually collects and retains moisture from the air, acting as the perfect breeding ground for rust. Even in warm summer months, humid air can leave moisture in the foam.
Remember, those plastic-shelled cases with foam interiors are for transport, not for long-term storage. Don’t repeat the mistake of a wealthy gun collector I know. He stored four valuable Colt Single Action Army (SAA) revolvers in individual foam-padded cases, and locked these away in his gun safe. A year later, every one of his precious SAAs had rusted, some badly.
Consider Military-Style, Triple-Layer Bags for Long-Term Storage
While we prefer Bore-Stores for regularly-used guns, if you have heirloom firearms that will be kept in storage for very long periods without seeing any use, you may want to grease them up and place them in the thin, but rugged three-layer storage bags sold by Brownells. The bags are made from a three-layer laminate of polyester, aluminum, and polyethylene film, with a shiny silver exterior. Though the laminate is thin, the Brownells storage bags are puncture-resistant, and have a 0% moisture transmission rating so moisture can’t get inside. These bags are also resistant to petroleum-based chemicals and they won’t break down even in contact with soil or moisture.
Here’s one VITAL bit of advice for using these bags. Be absolutely sure, before you seal up the bags, that your guns are DRY and that all metal surfaces have been coated with an effective anti-corrosive, such as BoeShield T9 or Eezox. Brownells’ storage bags are inexpensive. A three-pak of 12″x 60″ rifle sacks (item 083-055-003WB) costs just $22.99 — under eight bucks a gun. That’s cheap insurance for rifles and shotguns that may cost thousands of dollars.
Better jump on this money-saving promo boys and girls, because the deals expire tonight, at 11:59 pm CDT on July 12, 2019. And write down those Brownells Coupon Codes, because this special deal can save you some serious bucks: $10 off $100, $20 off $175, and a whopping $30 off $250. Plus, with each of these discount deals you get FREE Shipping as well. That could easily save you $10-$15 on a typical order (HazMat fees extra).
These Coupon Codes apply to both regularly-priced and SALE merchandise — pretty much everything currently in inventory (but no back-orders). Here are some of the current items ON SALE at Brownells.
Did you overlook your Memorial Day weekend shopping? There were some great bargains to be had at many of the USA’s best online vendors. But don’t fret. Many sales are still running, so you can take advantage of great sale prices. Here are SIX SALES that run through May 28th at 11:59 pm (or even later). But don’t hesitate too long.
1. Brownells — 10% Off $99+ and FREE Shipping
Brownells is effectively extending its Memorial Day Sale by 24 hours. Through 11:59 PM CDT on May 28th, you can get 10% Off Orders $99+ with Free Shipping. this applies to ALL products — Use Code PTD.
2. SWFA — 10% Off EVERYTHING — Optics, Rifles, Ammo & More
SWFA carries most of the top optics brands including Vortex, Schmidt & Bender, Kahles, Swarovski, Zeiss, U.S. Optics, Leupold, Leica, Nikon, Burris, IOR Valdada and more. SWFA also has a wide selection of rifles and pistols Everything in the store is 10% off through 11:59 PM CST 5/28/19. Plus FREE Shipping for $99.99+ purchases with code SHIP99.
3. Palmetto State Armory — 10% Off Guns and Ammo
Save on AR components, accessories, and ammo with Palmetto State Armory’s Memorial Day Sale running through 11:59 pm on May 28th (Tuesday). Get a stripped lower for just $39.99, or a complete lower with MagPul stock for just $149.99. There are dozens of other great deals.
4. Precision Reloading — $10 Off $100 or $30 Off $300
Through the end of the day today 5/28/19, at PrecisionReloading.com you can save $10 with Promo Code MD191 (for $100+ purchase) or $30 with Promo Code MD193 (for $300+ purchase).
The Memorial Day Sale at Creedmoor Sports is still underway. You get Free Ground Shipping and 10% Off Creedmoor-brand items. In addition, many other items are on sale.
6. Cabela’s — $10% Off Tuesday for Entire Order
This is a regular Cabela’s Promotion. Club members get 10% OFF the entire order with Code 19CLUB528. NOTE: You must be a Club Member.
Need primers? Here’s a great way to save on primers this summer. Now through August 15, 2019, There is a 25% factory rebate on Winchester primers. Here’s how it works. If you purchase at least $80 worth of Winchester-brand primers, you qualify for a $20 manufacturer’s rebate. That works out to a 25% savings ($20 is one-quarter of $80). Money saved is money earned!
And if you buy a larger quantity of primers you save even more. For example, if you buy $100 worth of Winchester primers, you get a $25.00 rebate. If you buy $200 worth of Winchester primers you get the maximum $50 back under this promotion.
This Winchester Rebate is good on purchases made on or before August 15, 2019, so you have plenty of time to shop. The rebate offer applies to virtually ALL Winchester brand primers – pistol, rifle, and shotshell. While we use Federal and CCI primers for most of our rifle hand-loads, we’ve favored Winchester pistol primers for many of our pistols. We’ve found Winchester pistol primers to be very reliable with all types of pistols and revolvers, and they work great with progressive reloading presses.
Shopping for gun parts, ammo, or reloading supplies? You will want to check out Brownells current Discount Codes. These Codes will qualify you for significant savings plus FREE Shipping. Use these Codes during check-out and the savings will reduce your net cost. Get up to $20 off on a $200 purchase — that’s a 10% savings. Plus the free shipping/handling could save you another $10-$20 easy. NOTE: Some of these discount codes may expire at any time, so don’t hesitate.
Headspace Gauges
Remember, those plastic-shelled cases with foam interiors are for transport, not for long-term storage. Don’t repeat the mistake of a wealthy gun collector I know. He stored four valuable Colt Single Action Army (SAA) revolvers in individual foam-padded cases, and locked these away in his gun safe. A year later, every one of his precious SAAs had rusted, some badly.
Here’s one VITAL bit of advice for using these bags. Be absolutely sure, before you seal up the bags, that your guns are DRY and that all metal surfaces have been coated with an effective anti-corrosive, such as BoeShield T9 or Eezox. Brownells’ storage bags are inexpensive. A 
