Readers often ask “What’s the difference between a Weaver scope rail and a Picatinny Rail?” The answer is not as simple as it seems. The dimensions of a Picatinny Rail should be consistent (from one rail-maker to another), since there IS a government spec. Conversely, there is some variance in “Weaver-style” rails. The width of the groove is the most important difference between Picatinny Rails and Weaver-type rails. “Mil-spec” Picatinny rails will have a grove width of 0.206″ while Weaver rails typically have a narrower, 0.180″ groove width.
Does your rifle have a Weaver Rail or Picatinny Rail? Check the dimensions to be sure.
A while back, Brownells had a helpful GunTech™ Article that discussed the Picatinny Rail vs. Weaver Rail. That article explained:
What are the differences between the ‘Picatinny’ and the ‘Weaver’ systems? The profile of the two systems is virtually identical. Depending on the quality of the machining done by the manufacturer, the two systems should be indistinguishable from the profile. The key difference lies in the placement of the recoil grooves and with width of the grooves. MIL-STD-1913 (Picatinny) grooves are .206″ wide and have a center-to-center width of .394”. The placement of these grooves has to be consistent in order for it to be a true Picatinny MIL-STD system. Weaver systems have a .180” width of recoil groove and are not necessarily consistent in a center-to-center measurement from one groove to the next.
In many instances, a Weaver system has a specific application that it is machined for, so interchangeability is not necessarily an issue. A MIL-STD-1913 system must adhere to the specifications listed above in order for it to be considered MIL-STD, since the military desires uniformity in the recoil grooves to allow for different systems to be mounted on the weapon with no concern for compatibility.
Now, what does this mean? Boiled down, it means that accessories designed for a Weaver system will, in most cases, fit on a Picatinny system. The reverse, however, is probably not the case. Due to the larger recoil groove, Picatinny accessories will not fit a Weaver system. There are, of course, exceptions to every rule, but for a good rule-of-thumb, [full-width] Picatinny won’t fit Weaver, but Weaver accessories WILL fit Picatinny.
Sierra Bullets has published load data for the 6mm Creedmoor cartridge, a necked-down version of the popular 6.5 Creedmoor. Sierra has released very comprehensive 6mm Creedmoor load data, covering fifteen (15) different bullets from 55 to 110 grains. NOTE: Hornady-brand brass was used for Sierra’s 6mm Creedmoor load tests, not the newer, stronger Lapua 6.5 CM brass with small primer pockets. Hand-loaders using Lapua 6.5 Creedmoor brass necked to 6mm may have to adjust their loads.
Sierra writes: “As soon as the 6.5 Creedmoor was released in 2007, a 6mm version was being envisioned. After the 6mm Creedmoor demonstrated its worth at 1000 yards it began to catch the attention of Precision Rifle Series (PRS) competitors. The 6mm Creedmoor is a great fit for those looking for an AR platform-friendly cartridge. It delivers velocities very similar to the .243 Win and yet fits the AR10 magazine length[.] The 30-degree shoulder makes this a very efficient case and helps prolong case life as well. The 6mm Creedmoor works well with powders such as H4350, [RE-16], RE-17, and Ramshot Hunter for heavier long-range bullet weights. Slightly faster powders such as RE-15, Win 760, and Vihtavuori N540 work well with lighter weight bullets.”
Sierra Bullets Tested for 6mm Creedmoor Load Data
55gr BlitzKing (#1502)
60gr HP (#1500)
70gr HPBT (#1505)
70gr BlitzKing (#1507)
75gr HP (#1510)
In developing its 6mm Creedmoor load data, Sierra tested a very wide selection of propellants, two dozen overall. For the smaller bullets, fast-burning powders such as Benchmark, H4895, and CFE223 were tested. For the heavier 100+ grain bullets, Sierra tested a selection of medium-burn-rate powders including H4350, Reloder 16, Reloder 17, Varget, and Superformance. Sierra did a very thorough job. We know this information will be welcomed by 6mm Creedmoor shooters.
Don’t know what powder to try first? For the 107-110 grain bullets, if you want best accuracy and low ES/SD, our Forum members recommend Alliant Reloder 16 and Hodgdon H4350. If you are seeking max velocity with the 110-grainer, look at Hodgdon Superformance and Reloder 19.
Here are Sierra’s 6mm Creedmoor Load Data Charts for 90-95 grain bullets plus the 107gr MK and 110gr MK. There are five other tables for other bullet types.
BONUS: PRB 6mm Creedmoor and 6.5 Creedmoor Load Survey
The Precision Rifle Blog compiled Load Data from PRS Competitors, for both 6mm Creedmoor and 6.5 Creedmoor. This is a good place to start. PRB surveyed the match loads for “173 of the top-ranked precision rifle shooters in the country”. One cautionary note: These PRS guys may be loading fairly hot, so work up gradually, 0.3 grains at a time. CLICK HERE.
Is factory 6.5 Creedmoor ammunition good enough to win a PRS or NRL competition? The answer is a resounding “YES” if we’re talking about Berger ammunition. Produced with Berger match bullets and premium Lapua brass, this Berger 6.5 Creedmoor ammunition demonstrated excellent accuracy, impressive velocity, and very good ES/SD numbers. When tested at 1000 yards with an MPA-stocked PRS rig with Rem 700 action, this ammo showed just half-MOA of vertical, and produced a group that would have been a 50-1X in F-Class competition. That’s quite impressive for a PRS rig.
This ammo test was performed by our friend Erik Cortina from Texas. The reigning SW Nationals F-Open champion, Erik is a top F-Class competitor who also shoots tactical matches (for fun and glory). A couple seasons back, Erik built a new 6.5 Creedmoor with a Remington 700 action. Though this rifle sports a top-shelf MPA chassis and premium Kahles scope, Erik calls this his “budget build” because it has a plain Rem 700 factory action rather than the elite Borden actions he normally runs. Erik’s actions of choice are the Borden Mountaineer for PRS and Borden BRM-XD for F-Class.
Erik posted: “Shot my budget 6.5 Creedmoor … with Berger Bullets factory ammo. I shot five rounds over the chrono to get speed. I used BC info from the box and it all lined up properly. I adjusted my ECTuner to tune load and it took just 15 shots to get it shooting well. It’s simple with good components.”
This Berger factory ammo features Berger 130gr Hybrid OTM Tactical bullets. The Lapua 6.5 Creedmoor cases have a large rifle primer. You can see this ammo displays good velocity with Extreme Spread and Standard Deviation rivaling good hand-loads.
Cortina says the very accurate Brux barrel and razor-sharp 6-24x56mm Kahles scope help achieve this kind of outstanding performance at 1000 yards. Here are the key components for Erik’s latest PRS rig:
Barrel Tuner by Erik Cortina — Fits Behind Muzzle Brake
This rifle features a barrel tuner designed and crafted by Erik Cortina. You can the EC Barrel Tuner alone, or, as you can see, the EC Tuner can be fitted BEHIND a muzzle brake. Erik tells us: “The EC Tuner allowed me to tune the barrel to my ammo rather than tuning the ammo for barrel as is done when reloading. With the tuner, there is no need to try different brands of ammo as they can all be tuned to shoot as good as possible in my rifle.”
Want to improve your understanding of Ballistics, Bullet Design, Bullet Pointing, and other shooting-related tech topics? Well here’s a treasure trove of gun expertise. Applied Ballistics offers dozens of FREE tech articles on its website. Curious about Coriolis? — You’ll find answers. Want to understand the difference between G1 and G7 BC? — There’s an article about that.
“Doc” Beech, technical support specialist at Applied Ballistics says these articles can help shooters working with ballistics programs: “One of the biggest issues I have seen is the misunderstanding… about a bullet’s ballistic coefficient (BC) and what it really means. Several papers on ballistic coefficient are available for shooters to review on the website.”
Credit Shooting Sports USA Editor John Parker for finding this great resource. John writes: “Our friends at Applied Ballistics have a real gold mine of articles on the science of accurate shooting on their website. This is a fantastic source for precision shooting information[.] Topics presented are wide-ranging — from ballistic coefficients to bullet analysis.”
Here are six (6) of our favorite Applied Ballistics articles, available for FREE to read online. There are dozens more, all available on the Applied Ballistics Education Webpage. After Clicking link, select Plus (+) Symbol for “White Papers”, then find the article(s) you want in the list. For each selection, then click “Download” in the right column. This will send a PDF version to your device.
Want to show off some groups you’ve shot? Or keep a handy pack of mini-targets in your range kit? Then check out this unique product from stockmaker Bell & Carlson. Shoot’n Aces cards feature a 1-inch black square aiming box with a 1/2-inch inner square. These cards are normal poker-playing-card size, 3.5″ high x 2.5″ wide (89 × 64 mm). Shoot’n Aces cards come 56 to a pack. Carry a few extras in your wallet or a pack in your vehicle glove compartment and you’ll always have a precision target to shoot at the range. Cards can be stapled or taped to target stands.
Sniper Central says these cards work well as targets: “The bold square is easy to pick up with the inner white portion making a nice aiming point. The material of the cards is the same as normal playing cards and the bullets make a very nice hole when passing through.” The sharp edges of the bullet holes makes it easy to measure group sizes with precision.
Each pack of Shoot’n Aces contains 56 premium-quality target cards. If you want some, order Bell & Carlson item SA-2006. This is a set of four (4) card-packs with 56 cards per pack (224 cards total) priced at $20.00 (i.e. $5.00 per pack).
Leveraging the incredible success of the 6.5 Creedmoor cartridge, ammo-makers and rifle manufacturers have teamed up to produce a bigger Creedmoor cartridge — the 7.6 Creedmoor. The latest addition to the Creedmoor line gets its name from its 7.62mm bullet dimension. Yep, that makes it a .30-cal cartridge, but the creators stuck with the metric title for consistency. Makes sense. We like the way “7.6 Creedmoor” sounds and we bet consumers will too. The 6.5 Creedmoor has been a singular success — it is by far the most popular new cartridge introduced in the last decade. We think the 7.6 Creedmoor could become equally successful in short order.
In creating the new 7.6 Creedmoor, the product engineers were primarily concerned with accuracy, reliability, and compatibility. In a brilliant marketing stroke, the 7.6 Creedmoor’s designers crafted this cartridge to be 100% compatible with existing .308 Winchester and 7.62×51 rifles. So you can shoot the 7.6 Creedmoor safely in your existing .308 Win deer rifle or F-TR rig. As one ammo-maker’s marketing manager told us: “The 7.6 Creedmoor gives you everything you liked about the .308 Win, with a trendy name and the undeniable Creedmoor cachet. The 6.5 Creedmoor has become hugely popular. We expect the new 7.6 Creedmoor to do as well, or better!” We agree. Consider this — the 7.6 Creedmoor offers much better barrel life than the 6.5 Creedmoor, along with better bullet selection, particularly for hunters. With these advantages, how could the 7.6 Creedmoor not become a huge hit? The Creedmoor name alone should ensure success.
We discussed the new 7.6 Creedmoor with Dennis DeRille, one of the “founding fathers” of the 6.5 Creedmoor. Dennis said — “The Creedmoor name is synonymous with innovation and tactical success. This new 7.6 should live up to its name as it delivers .308 Win performance in a package for the 21st Century.”
Reassuring .308 Win Ballistics and Die Compatibility
Another great feature of the new 7.6 Creedmoor is that you can use existing .308 Win dies and reloading components. That excited one PRS shooter: “I had all this old .308 brass and .30-Cal bullets sitting around. When I heard about the 7.6 Creedmoor I said ‘Wow this is great, I can use this stuff in a Creedmoor now’. I know it will be accurate based on the name alone. That’s cool — tacticool!”
Because the new 7.6 Creedmoor shares case capacity and design details with the venerable .308 Win, it also shares the .308 Win’s impressive ballistics performance. “Whatever you can do with a .308 Win, you can do with the 7.6 Creedmoor… and then some!” says Hornady. Here is a chart showing projected velocities for the 7.6 Creedmoor with various barrel lengths and bullet weights.
NRA Approves 7.6 Creedmoor for F-TR Competition
Currently, NRA competition rules restrict F-TR rifles to the .308 Win (7.62×51) and .223 Rem (5.56×45) chamberings. But that’s going to change. Starting in June 2026, the NRA will allow 7.6 Creedmoor rifles in all F-TR matches. In addition, the 7.6 Creedmoor can be used in service rifles such as the popular M1A. It’s great to see this old battle rifle updated with Creedmoor accuracy and performance.
USA and Foreign Ammo Makers will Produce 7.6 Creedmoor Ammo
7.6 Creedmoor factory-loaded ammunition will be available from all major USA ammo-makers including Federal, Hornady, CCI, and Remington. As well, foreign ammo-makers Hirtenberger, Sellier & Bellot, and Prvi Partizan have pledged to produce 7.6 Creedmoor ammunition. That’s good news for shooters who want affordable Creedmoor ammo. One ammo-maker told us: “The whole industry is excited about the 7.6 Creedmoor. To be honest, .308 Win ammo sales have been declining for a number of years. Now we can repackage those same great components and market them to a new set of consumers reared on the 6.5 Creedmoor. This is a great deal for ammo-makers, who know how excitable Creedmoor fan-boys can be!”
This Armalite AR-50A1 .50 BMG rifle was modified by G.A. Precision.
If you’re a fan of big boomers, and love shooting steel, then definitely watch this Wide Open Magazine video. This covers a .50 BMG build by our friends at G.A. Precision (GAP). The rifle started as an Armalite AR-50A1 ($4750.00 MSRP). Then GAP fluted the barrel and swapped the factory muzzle brake with a more compact brake from American Precision Arms*. Then, as modified, the entire rig was given a rugged Cerakote finish.
The video has nice background music (pretty loud), great aerial drone footage, and of course some serious firepower. Using Hornady .50 BMG ammo, GA Precision’s George Gardner and his Wide Open friends shoot the big Fifty from the bench as well as prone. Enjoy!
About the .50 BMG Cartridge
The .50 Browning Machine Gun (.50 BMG, aka 12.7×99mm NATO or 50 Browning) is a cartridge developed for the Browning .50 caliber machine gun in the late 1910s, entering official service in 1921. Under STANAG 4383, it is a standard cartridge for NATO forces as well as many non-NATO countries.
John Browning had the idea for this round during World War I in response to a need for an anti-aircraft weapon, based on a scaled-up .30-06 Springfield design, used in a machine gun based on a scaled-up M1919/M1917 design that Browning had initially developed around 1900. According to the American Rifleman: “The Browning .50 originated in the Great War. American interest in an armor-piercing cartridge was influenced by the marginal French 11 mm design, prompting U.S. Army Ordnance officers to consult Browning. They wanted a heavy projectile at 2700 FPS, but the ammunition did not exist. Browning pondered the situation and, according to his son John, replied, ‘Well, the cartridge sounds pretty good to start. You make up some cartridges and we’ll do some shooting’.”
* In the video, George mistakenly says “American Patriot Arms”, but the brake is made by Georgia-based American Precision Arms.
Brian, a gunsmith at GA Precision, built this rimfire rig with GAP colleague Anthony Soukup.
On his Facebook page, Tactical competitor Bryan Sikes posted a photo of a rimfire rig we really liked. Brian works at GA Precision. He and fellow GAP gunsmith Anthony Soukup built this rifle. With a modified Rem 40X action, Manners stock, Bartlein barrel, and Mack Brothers suppressor, this rig has top-quality components stem to stern. And Bryan tells us this rifle performs as good as it looks: “This is the baddest little .22 LR trainer ever. I’m stoked about it. With the barrel length and can, it’s the exact length of my regular comp rigs.” With length, balance, and ergonomics near identical to Bryan’s centerfire competition rifles, this 40X is a superb training tool.
Many readers wanted to know about the bottom metal and the detachable box magazine. Bryan Sike reveals: “The magazine setup is designed specifically to replicate my actual competition rifles. The bottom metal is for use with AI magazines and uses a standard M5 type inlet just like any centerfire completion rifle. In this case with the .22LR, Mike Bush designed a high reliability rimfire magazine using the same outside dimensions as an AI magazine. This rifle was built no different from any other. The action was modified and trued, barreled, fully bedded, etc. using ALL components common to centerfire match rifles.” The Rem 40X action was modified by Modacam Custom Rifles to work as a repeater with box mags.
Bryan adds that a new rimfire action is in the works: “My preference is modified Remington 40X actions and the soon-to-be available, V-22 action from Mike Bush. Both of which are TRUE repeaters and don’t feed from a Savage magazine. This rifle feels nothing like a .22 LR and that was the whole point.”
Why You Need a .22 LR Tactical Cross-Trainer
Many guys who shoot long-range tactical matches practice with .22 LR rifles of similar configuration. Rimfire ammo is way more affordable than centerfire, you do not need a big range facility, and shooting rimfire saves wear and tear on your centerfire rifle. Further, for learning how to read the wind, there really is no better training tool than a .22 LR, even as close as 50 yards.
Our Friend “DesertFrog”, who shoots tactical matches in Southern California, explains: “I used to shoot an average of 200 rounds of .308 Match ammo a month for training (50 per weekend). These days I shoot maybe an average of 50 rounds of .308 Win per month and probably around 600 rounds of .22 LR. Using mainly the .22 LR for practice did NOT hurt my standings in actual competitions. I shot my .308 just as well in matches, but saved the cost of hundreds of rounds of .308. If I didn’t reload and was still buying boxes of Federal Gold Medal Match .308 Win [at $1.90/round], this would be a savings of [$350 per month on the centerfire ammo.]” Money saved is money earned.
Targets for Rimfire Cross-Training
SPECIAL BONUS–Rimfire Tactical Precision Targets
These FREE targets by DesertFrog are offered in Adobe Acrobat format for easy printing. CLICK HERE to download all six targets as a .ZIP archive.
Enjoy the Shooting Sports USA Archives
As we head into spring, many Americans will be spending more time at the range. And competitors will be shooting in rimfire and centerfire rifle matches throughout the country. Here’s an opportunity to learn competition skills, gun tuning methods, and reloading techniques from leading experts. A vast resource of gun-related content is available online for FREE. Check out the Shooting Sports USA Articles Archive. SSUSA maintains a vast digital library with hundreds of articles going back to June 2009.
It’s easy to find back issues of Shooting Sports USA. Here’s how: First, navigate to the latest SSUSA Online Issue. Then click on the “ARCHIVES” icon in the upper right area (indicated with red arrow). When you click on “ARCHIVES”, a window will open with a selection of Shooting Sports USA magazine covers/dates in a vertical column. The most recent issue (November 2025) will appear at the top. You can then scroll down — use the vertical scroll bar to go from November 2025 (the latest issue) all the way back to June 2009. Click any issue cover to read.
NOTE: It’s wise to use these archived digital magazine resources while you can. The NRA will continue the Shooting Sports USA website, but it has halted release of the monthly Shooting Sports USA digital magazines. Thankfully however, there will be new content posted regularly on the Shooting Sports USA website at SSUSA.org. Shown below is a review of the Tikka T3x Ace Target rifle from December 2025.
Click photo to read online Tikka T3x review.
How to Find and Save Articles
To search back issues, select “MORE OPTIONS” from the toolbar (top left). Then click the “SEARCH” button. When that opens, select either “Search Archives” for ALL back issues or “Search Only this Issue”. When you’ve made your choice, enter your search term(s). For example, you can search for “Camp Perry” or “Palma” or “F-Class Championship”. You can also save any archived issue as a PDF for viewing offline. Just click “SAVE” to download the article you’re currently viewing/reading.
Read Sample Articles
Here are a couple of our favorite SSUSA feature stories from recent years. There are hundreds of other informative articles worth reading.
Here’s a new option for hunters and tactical competitors who want to range targets and call windage/elevation corrections using their spotting scopes. Vortex is now offering Reticle Eyepieces for its Viper HD spotting scopes. Available in both MRAD and MOA versions, these fixed-power 33.5X eyepieces feature ranging reticles with handy hash marks. This allows target ranging, plus competitors can “make accurate shot calls… with subtension lines for holdover and windage corrections.”
Vortex states: “The all-new eyepiece makes measuring target range and calling shot corrections easy, with a diopter ring that allows shooters to get the reticle dialed to their eyes, and level with the horizon line, no matter how their scope is setup.”
Powering the new eyepiece is a fixed, 33.5X magnification ocular lens. This provided plenty of power most hunting and competition scenarios. The eyepiece glass is protected with ArmorTek and XR lens coatings. These easily-installed ranging eyepieces, both MRAD and MOA, are designed for a wide field of view so user won’t miss a single vapor trail or bullet splash.
Ranging MRAD — Hashmarked ranging reticle using MRAD-based subtension lines for ranging, holdover, and windage corrections. Secondary ranging references facilitate rapid range estimating.
Ranging MOA — Hashmarked ranging reticle using MOA-based subtension lines for ranging, holdover, and windage corrections. Secondary ranging references facilitate rapid range estimating.
These eyepieces have fixed, 33.5-power magnification. “Street Price” is about $200.00.
Cortina says the very accurate Brux barrel and razor-sharp 6-24x56mm Kahles scope help achieve this kind of outstanding performance at 1000 yards. Here are the key components for Erik’s latest PRS rig:
