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Which Caliber Would you Choose?

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Which Caliber Would You Choose?  The F4 Small Frame AR10 gives you a ton of choices!

Do you hunt? How about .243 Remington or 7mm-08.  Do you compete in the Precision Rifle Series?  Then look at .308 Winchester, 6.5 Creedmoor, or even the badass and little known .22 Creedmoor that is an absolute burner.  Offering multiple calibers in the AR10 platform is nothing new, offering a wide range of calibers in a Small Frame AR10 is.  The F4 SF-10 AR15 sized from the magwell back; utilizing quite a few Mil-Spec AR15 parts.  And we make the lightest AR10 platform in the industry.  It’s not a skeletonized “Tacti-cool” rifle with Titanium parts; it was done by significantly reducing the size of the Receivers, Barrel Extension, and Bolt Carrier Group (BCG).

In just a few weeks we’ll be releasing our SF-10 in the following calibers and configurations:


  • .308 WinchesterF4 Defense F4X Small Frame 308
  • 6mm Creedmoor
  • 6.5 Creedmoor
  • .243 Winchester
  • .260 Remington
  • .22 Creedmoor
  • 7mm-08


  • .308 Winchester
  • 8.6 Creedmoor
  • .45 Raptor

Military and Law Enforcement:

  • .308 Winchester

Hunters, we have every game animal covered in North America.  Size and weight matters, when humping it through the mountains, forest, or desert.  The .243 Winchester and 7mm-08 have been a staple for large game hunting for a very long time.  The 7mm-08 now comes in a semi-automatic lightweight rifle. The 7mm projectile is very versatile and suitable for all of North America’s game animals, good ballistic performance and power enough to deliver knock down velocities over distance.

This medium capacity cartridge is the .308 Winchester necked down to the popular 7mm caliber. The 7mm-08 cartridge has the same powder capacity as the .308 Winchester, but it fires more narrow, higher B.C. projectiles in any given weight category, thus it shoots faster and flatter, drifts less in the wind and retains more energy downrange.

Predators, particularly coyotes, don’t stand a chance with the .22 Creedmoor sending an 80 grain Berger bullet downrange at 3600fps.  Lights out!

PRS, 3-Gun, and the various Sniper competitions; we’ve got your back.  You have a wide range of calibers to choose from; 6.5 Creedmoor, 6mm Creedmoor, .22 Creedmoor, .308 Win, .260 Remington…..in a 7.5lb rifle.

And our LE/MIL brothers.  It just makes sense that a 16” .308 Win that weighs 6.49lbs holds a significant advantage in tight spaces and on the move.  The large caliber stopping power, size and weight of an AR15, and versatility of a semi-automatic rifle…..again, it just makes sense!









F4 Defense .224 Valkyrie Release and Small Frame .308 Update!

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Released:  The F4 Enhanced Battle Rifle in .224 Valkyrie


F4 Defense is proud to announce the release of the F4-15 Enhanced Battle Rifle (EBR) chambered in .224 Valkyrie.  Some very bold statements were made last year concerning the performance of the Valkyrie; a cartridge based on a .30 Rem/6.8 SPC case necked down to accommodate a .224 projectile.  We rarely jump on “new fad” calibers, but we had to test and evaluate whether this cartridge could live up to the hype surrounding it.  We can confidently say it’s a damn good cartridge.  The fact that shooters can buy off the shelf ammo is significant as most do not hand load.

After testing various twist rates and barrel lengths, optimized for the 90gr Sierra Match Kings and now with the long anticipated Hornady 88 Grain ELD Match ammunition; F4 Defense settled on a 20” 1×7 twist because it just plain works. The “need” for a tighter twist is simply not correct and we’ve proven it, it’s not surprising that you see manufacturers now jumping off the tight twist and going with a 7. A tighter twist than necessary lessens barrel life and can also restrict you from using a wide range of projectiles. Our F4 EBR consistently shot ½ MOA with pre-production Federal Gold Medal Match. So……that brings us to today and how different the production ammo is from Federal, compared to the fantastic pre-production lots.  To put it bluntly, it’s just not that good and wildly inconsistent.  We have 1/2 MOA rifles that turned very inconsistent with the new production ammo and starting shooting 2 and 3 MOA, which is completely unacceptable.  Shooting handloads brought the accuracy right back down to sub 1 MOA.  Federal needs to get this issue fixed and fixed fast.  The Hornady 88 Grain ELD-Match is fairing much better at this time, even if it’s just a bit underpowered.  We shoot suppressed most of the time and didnt notice it at first, but that is not a show stopper and can be dealt with.  Working with one of the top barrel manufacturers, it was discovered that the production Federal ammo had as much as .020″ difference from tip to ogive in some of the lots we measured.  That is very inconsistent and led us to believe it may also be an issue with the Sierra projectile or combination of the two.  Nevertheless, we’ve seen what Federal and Sierra are capable with the pre-production lots of ammunition and it was top notch all around.  Let’s hope they swallow their pride and tighten up their QA and produce the same level of quality in production runs going forward.  We believe in the caliber and the potential of the 90 Grain Federal Gold Medal Match, but until we see some change, we’ll be loading our magazines with Hornady.


SF-10:  Small Frame .308 / 6.5 Creedmoor Update

We had planned to have the Small Frame .308 and 6.5 Creedmoor ready this past spring but ran into some issues with manufacturing capacity and that forced us to shuffle the schedule, which of course takes time which triggers the inevitable delays in release.  After months of churn, we’re happy to report that production has stated and delivery will begin in full this October and we’ll start filling the long list of pre-orders and Law Enforcement contracts.  While it has taken longer than anticipated to bring this platform to market, it doesnt change the fact that it’s going to transform the AR10 market.  Having an equally performing and accurate AR10 platform in a package that dishes out less recoil and weighs considerably less overall, just makes sense.  What’s not to like about a soft shooting 6.4lb .308 that is every bit as accurate than its big brother, the AR-10.  Sign up on the website to get updates on new product releases and the release of the SF-10.  We are still taking pre-orders via email at info@f4defense.com.

The Process: Small-Frame AR-10/.308 Testing Day 1

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The Process:  Bringing the F4 Defense Small-Frame AR-10/.308 to Market – Day 2

F4-X Small-Frame .308

Testing Begins……Again

The magazine catch fix worked fine in the shop and held magazines firmly, so we headed to the range to do some testing.  Zero issues, running both lowers.  Magazines held as they should so we’re are past that issue.  With the mag catch in the rear view mirror it was time to put some rounds downrange.

I setup at 100 yards and just started feeding this thing ammo.  Everything from cheap Federal 149 grain to the better quality shelf ammo, Federal Gold at 175 grains.  To say we were pleased with performance on the first day out would be an understatement.  Because we were running reliably with a wide range of ammo we decided to throw a suppressor on there and shoot a few rounds through an Osprey from SilencerCo.  Running suppressed didn’t change our point of impact and it ran pretty damn well VIDEO.  We had a double feed and a few times the bolt failed to hold open on the last round.  The only issue I would label as a concern would be the cratering we saw on the primer.

Firing Pins

We use the DPMS Gen II Bolt Carrier Group along with some of the other parts that allow us to make a Gen II Compatible weapon system.  After a discussion with our engineer and a senior engineer with Remington/DPMS, it turns out that we had the older BCG design.  The older design had a larger firing pin diameter at the tip (0.075) and opening on the bolt face. The new design was reduced to (0.065) and I’m sure that will take care of the cratering on the primer.  We’ll test it in the next few days and see what happens.  Extraction was good, if a bit hard from having two (2) ejectors on the bolt.  This was the first experience I’ve had with dual ejectors, but no issues noted and the brass was ejecting consistently.

At F4 we pride ourselves on building sub-moa weapons and we aren’t going to accept anything less with fielding a new platform.  Here are the results from our limited accuracy testing.

  • Hornady Superformance .308 GMX, 150 grain: 5-shot group at 0.915 MOA
  • American Eagle 7.62x51mm, 149 grain: 5-shot group at 1.192 MOA
  • Federal Gold .308, 175 grain: 10-shot group at 0.783 MOA

The Federal Gold performed very well in our Black Hole Weaponry Barrel.  Here are the specs on our barrels.

  • Length: 18”
  • Gas System: Mid-Length
  • Twist Rate: 1 x 9.76
  • Rifling: 3 Land Polygonal
  • Profile: Standard/Light

BHW makes these barrels exclusively for F4 and they are DPMS Gen II compatible.

In closing, I just want to touch on a few observations.  The recoil was relatively light, especially considering this Small-Frame .308 is less than 8lbs.  It was comfortable to shoot.  Over the next few weeks we will start to tweak our gas settings and buffer system to improve the platform.  We also want to explore going with a rifle length gas system.  Once we work out a few kinks, we have 12 rifles going to testers across the country so we can do a proper T&E of these F4-X Small-Frame .308’s.

We are keeping a handful of rifles to continue our own testing and do a side x side comparison of two barrels.  Our Black Hole Weaponry barrels and the DPMS Gen II compatible barrels by Rainier Arms.  The guys over at Rainier wanted us to evaluate their barrel and possibly field them with our rifles.  I know quite a few of you would be interested in seeing how they perform so we’ll do some testing and post updates in this blog series.

As we get closer to release, we are going to start exploring the other calibers we plan to carry, which are:  6.5 Creedmoor, .260 Remington, .243 Rem and/or .264 LBC.

Standby for updates and please ask questions and post comments, I would love to hear from you guys as we go through this process.  Thanks for checking in!


Dave Fairfax, F4 COO

The Process: Bringing the F4 Defense Small-Frame AR-10/.308 to Market

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The F4X: Small-Frame .308

We have had several folks contact us with questions about the F4X (Small-Frame .308) and when it will be ready.  Being completely up front, the best I can do is give an estimate, but that is entirely based on Test & Evaluation.  This led to quite a few questions on the process of bringing a new product to market.  And of course, there are many ways to approach this, we will just document what we are doing and changes we make along the way to field a top-notch weapon system.

Design Goals

Obviously, size and weight were very important, right behind performance and reliability.  Being a small-frame system we wanted the weight to be in line with that type of design.  Weight seems to be a major factor in today’s market and there are quite a few differing opinions.  We determined during design that we wanted a sub 8 pound .308/7.62 (Dry).  This drove several design decisions.  The Adaptive Rail System – Lite (ARS-L) was originally developed for the Small Frame .308.  After the feedback we got from industry and shooters, it was decided to develop one for the F4-15 as well, at least in the 12 and 15-inch configurations.

Before I talk specific decisions on how and where to cut weight, I think it is crucial to talk about weight distribution and the importance of making weight reductions in the right places/components to keep the rifle well balanced.  The last thing we wanted to do is develop a rifle and then load it up with a bunch of lightweight aftermarket parts.  So naturally we started with the center; the receivers.  The great thing about strategic machining is that you can cut weight and make it great looking at the same time, they usually go hand in hand.  So, we got started on machining certain areas of the receivers to give it a lightweight balanced feel.  So far that has been very successful, especially removing material from behind and under the brass deflector which is just a massive section of Aluminum.  Additionally, all the recessed cuts throughout takes a little bit of weight off at a time.

The 15.5 “ARS-Lite comes in under 11.5 ounces with the barrel nut so that was a good fit.  The barrel, which is crucially important was another decision we went back and forth over for months.  Because our barrels for the F4-15 are manufactured for us by Black Hole Weaponry, it made sense to start there.  We chose a profile that is light/standard but with enough mass to balance and handle recoil from a .30 caliber weapon.  The barrel is 18 inches with a 1×9.73 twist rate and of course features their kick-ass polygonal rifling.

We are now testing and evaluating different buffer systems, to dial it in even further.  The F4X uses a mid-length gas system with an adjustable gas block for fine-tuning.  What we ended up with was a 7.53lb Small-Frame .308 that is still heavy and balanced enough to shoot comfortably.  With the introduction out of the way, let’s jump right into day 1 of testing.

Testing Day 1

The F4X felt good and shot accurately, but we had a short day because the magazine was dropping after each shot or when the Bolt Carrier was driven closed.  Oh, the joy of new weapons system.  We immediately looked at 2 potential problems.

First, the magazine catch position, depth, and movement.  The other area that may have potentially caused this issue is the broaching of the magwell.  The broaching process is straight forward and chances are, that was not the reason.  You can see a short video of magwell broaching here:  Broach Video-1  As it turns out, it was the magazine catch slot depth.  We were too shallow by .058 +/- .005.  We updated the models and prints and fortunately we are removing material, rather than adding.

Mag Catch Slot Depth

These types of hurdles are the exact reason we only fabricate a few receivers, before we run 10-15 T&E guns for full-scale operational testing.  Fortunately, this is an easy fix and we’ll be back in business almost immediately.  The areas we were able to evaluate did great.  Ejection and timing was solid, recoil impulse was manageable and comfortable, and accuracy was good.  No surprise there considering the barrels we use.  Of course, these were very limited sample sizes due to it being the first run and the issue with the magazine catch.  All-in-all it was a great start.  We will continue to update the blog as T&E continues.  If any of you guys have questions/comments please don’t hesitate to reach out, we would love to hear from you, as this blog is designed for you guys, not us.  The point of our blog posts is to inform the 2A community and to share the experiences we have.  When building F4 from the ground up there was very little inside information into the industry.  We are going to lift the curtain and give everyone a glimpse at what we are doing behind the scenes.  It also needs to be stated that there are several ways to accomplish what we are writing about, but we’re just going to share our process.

Thanks for reading, stay tuned for more updates.

Dave Fairfax, COO

Why We Leverage Established OEMs

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This blog post was a bit difficult to put on paper, not because I’m lacking for content, rather it is a case of sharing our experiences while not offending any one company.  For obvious reasons, we’re not going to name companies but just want to give you guys a glimpse at the experience we’ve had finding an OEM or multiple OEMs for different AR-15 and AR-10 product lines.  First, not being a machinist by trade, I never intended to open a machine shop.  Outsourcing in my opinion is the way to go in most situations, including ours, but certainly not all.  Outsourcing fit our business model and kept costs in check, not that its inexpensive to enter this market the right way, but the equipment, labor, building, etc. in opening a shop is exorbitant to say the least.  I think it would shock a lot of the community to see how many companies outsource because most of them do.  Some may establish minimal manufacturing capabilities in-house but the clear majority outsource most if not all their products.  At one point, it seemed that there was a stigma attached to companies not manufacturing in-house and brands were hesitant to say otherwise.  For those that look down on outsourcing, I would just say this:  As a company and brand why would you not want to utilize the expertise of established machine shops and fabricators.  There are so many elements to bringing new AR-15 products to market, so it makes sense to seek out that expert machining capability and take advantage of the vast experience these OEMs have.  Of course, there are many ways to attack this, but we’ll stick with outsourcing because that is the way that works for us.  Now having said that, there are certainly drawbacks as well.

Before we jump into this, it needs to be stated that there is a clear difference between outsourcing and offshoring.  We outsource to American companies only, never outside the US, and we never will.  I won’t waste any time with why, I think we all know why patriotic companies such as ours are adamant about keeping everything in America, supporting American companies and American jobs.  We live and breathe “AMERICA FIRST” and that’s never going to change.

I’m also not going to go into a textbook pros and cons of outsourcing, but I do want to touch on a few.  First, is obviously cost.  Starting a firearms manufacturing company is expensive, but pales in comparison to standing up a machine shop.  As mentioned above, utilizing experts across the firearms industry is advantageous as you can leverage that expertise in each sector, then apply your in-house experience and knowledge to bring it all together.  Let’s look at an AR15 Bolt Carrier as an example.  Partnering with companies that are setup for that type of fabrication are both affordable and efficient.

Check out this AR15 Carrier fabrication here:


                 We do not outsource ANY of our design work; it’s done 100% in-house by our engineering team. 


Now, some drawbacks to outsourcing in our experience.

TIME:  First and foremost is time, time, and time.  We are obviously not our OEMs only customer and the waiting can be extreme sometimes, especially when you’re making design changes.  In our case, the OEM is out of state and the shipping and time lost shipping products back and forth cannot be understated.  We cannot make immediate modifications and/or improvements in real time.

LOCATION:  Not only do you lose precious time sending products back and forth, we also lose the ability to sit in the same room and go over design changes, improvements, etc.  Doing it remotely has its challenges.  Photos and video help, but is not even close to being as effective of sitting in the same room.

COMMUNICATION:  Next is the lines of communication between us and our OEM.  This has been difficult for us and it’s a balance between wanting to be updated regularly but not constantly hassling our OEM for updates.  This does not apply across the board, as we have a fantastic line of communication with our Extruder.  So much time is lost when working remotely and not having regularly scheduled updates.

ECONOMIES OF SCALE:  Minimum volume is always an issue when starting out.  It’s a balance between ordering enough product to keep it economically feasible while not blowing through capital.  Our current OEMs have been very accommodating to us and patient as we work our way through an order.  And its mutually understood that both companies serve to gain when the kinks are worked out before full rate production.

These are but a few of the reasons we outsource and some of the drawbacks as well.  It took a good bit of trial and error to find the right OEMs and there are still issues to be worked out.  It’s a continuous process of improvement and attention to detail cannot be overlooked.  While we are probably a pain in the ass for some of our OEMs, I think they understand our drive toward perfection.  In the future, we would like to bring some capability in-house; particularly R&D and prototyping.

As any business partnership, there are highs and lows.  But overall, we are satisfied with those OEMs we are working with.

Dave Fairfax, COO



How to Start an Ar15 Rifle Company

How This AR15 Rifle Company Got To The Starting Line

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What’s up guys, Dave here from F4 Defense.

This is the first blog post of a series I’m going to write about our experiences as a new AR15 Rifle company in the gun manufacturing world, along with the challenges all businesses face and how we navigated our way around, over, or through and position ourselves to enter the market.

The F4 Defense blog will have one purpose: share our stories, knowledge, tips, tricks, pitfalls, successes and setbacks about what it’s like to start a company in the gun manufacturing world. We are in the same position as so many companies before us and feel blessed to be given the opportunity to enter a market that is so important to us personally. I hope you’ll enjoy, ask questions, make comments, and follow along as we write about what we’ve been up to and experienced in the past year, and follow along as we design, prototype, test, market, and release new products leading into SHOT 2018 and beyond.

Where to start?

When researching and exploring entry into this market we did all the textbook business plans, market and competitor analysis, etc. But what we really wanted and needed—was an inside look at the manufacturing of firearms. We researched online, got into SHOT show, started building crucial relationships, and asked a lot of questions. During our research we found that there was very little information on the inside operation in the industry; even something as simple as how they build their rifles. Jon Patton of The Gun Collective fame produced and released the first video that I’ve seen, which details the assembly line at Daniel Defense. We have been building, testing, and shooting the AR platform for years but were still very curious to see how successful companies operate.

We realized that in order to succeed we needed to take a look at how many other manufacturers fabricate firearms in-house. Surprisingly, there were a ton of successful companies that outsource the fabrication of parts. We looked at multiple machine shops that manufacture firearms and took bits and pieces from each one to figure out the best way for us to provide our customers the best rifles possible. From a design and test perspective we have an extremely talented team of engineers; however, we also needed to aggressively attack the machining side of the equation. Even though we are outsourcing to an American OEM, we still sought to learn every possible thing about the entire process.

This blog is designed and intended to bring some of the burning questions I wanted to be answered when starting a new company to the surface so that you can learn from my mistakes and successes. Whether you are contemplating a new business venture, or want a look behind the curtain that is the firearms industry or just curious about the industry in general, then follow along to see our growth and perspective in this industry as a new business.

We’ve put this list together on what we feel are some of the most important steps in the process, but it’s certainly not the only way to build a new company, its just a list of what all companies deal with entering the market.

  • Market analysis, product assessment, and entry barriers
  • The advantages and disadvantages of outsourcing
  • Finding and evaluating a machine shop
  • Finding and evaluating an extruder
  • Rifle building process, testing, and standards
  • Choosing companies to align with and what parts to use that we don’t currently design (i.e. barrels, stocks, grips, etc.)
  • 3D Printing in metal and plastics
  • Finding a mentor
  • Patents
  • Prototyping
  • Marketing budget and balancing money spent on traditional marketing versus social media
  • Research and Development
  • Lessons Learned
  • Customer Service
  • Transparency

As we get going…

As we get going, if there’s something we’ve experienced and can speak to—we certainly will. We would also love to hear your thoughts on the whole idea behind this blog, of sharing our experiences with all of you that either want to enter the market or are just curious of what goes into the startup of a small business manufacturing small arms.

None of this would be remotely possible without living in the greatest country to ever exist. America and its capitalistic backbone allow the little guy to take a shot at success and that’s something we’ve never taken for granted and never will.

In the next post, I’ll write about how we went about finding a machine shop and the obstacles we’ve overcome.

Thanks for checking out our Blog and please don’t hesitate to share your thoughts and opinions on any of these topics or any topics not listed.

Dave Fairfax, COO