pr-fit stainless steel barrelsHigh-volume shooters require sources for precision barrel work. As a precision-minded gunsmith, firearms business owner, and competitive shooter, I know why precision pre-fit barrels and precision-made actions are a great value to the marksmen who choose to do business with us.

There are three main factors for choosing actions to pre-fit barrels too. The hardness of the steel, action head spacing, and timed threads. Let me discuss these factors in more detail and talk about actions we have chosen to pre-fit barrels too.

Pre-fit barrels from our shop work as well as any barrel we do with the action in hand. You might ask why is this? It is because we do the research on the actions that hold tolerances and have the metallurgy “hardness” to handle repeated barrel replacements. These actions I will be talking about are made by true craftsmen that are also precision minded and test the quality of their products.

prefit barrels Go Gauges and Measuring Tools

Headspace on a rimless cartridge is the measurement from the face of the bolt to the datum measurement on the shoulder were the cartridge had its datum measurement designed. This is always referenced and built exactly into a “go” gauge by quality tool makers for gunsmiths and barrel makers to reference their work to specific cartridge design. Therefore, it is super important to use action companies that maintain their action face to bolt face measurements to very tight tolerances. We set our pre-fit barrels headspace off these measurements provided by the action makers and measurements are also verified in house. We also work tightly with premium action makers to maintain the quality of our pre-fit barrels to their actions.

Proper head spacing and maintaining it from barrel to barrel also helps the reloader greatly. When the user of these pre-fits does not need to adjust their resizing die to bump the shoulder back it’s because the pre-fit barrel was made to the exact same specifications as the last one. This is not done by just anyone. This is only done by good documentation, operator consistency, and CNC machining the threads and chamber to repeatable depths. We can adjust headspace in our machine by .0001” increments. That can only be done with the proper machine and set-up.

We document and verify all specifications and measurements of our pre-fit actions we offer and pre-fit barrels we machine. This helps the user by not needing to send his action in for barrel fitting or worry about changing out brass from barrel to barrel if it still has more firing left on it. This saves the user a great deal of frustration and money.

Why timed threads on the action are a must when it comes to pre-fitting barrels?  There are two main reasons here:

  •  ATF requires all barrels to be engraved with the caliber and cartridge information for safety reasons. This would be impossible to guess were to engrave this unless the threads are started in the same orientation every time from the action maker. This also allows us to engrave the caliber right above the stock line.
  •  some barrels need to be timed to the bore curvature at the muzzle end. This curvature needs to sit in the 12 o’clock position in relation to the top of the action and the highest point of runout on the muzzle. Therefore, we use very high-quality cut rifled barrels from Hawk Hill Customs because they have true craftsmanship and quality in mind. Our stainless-steel barrel supplier makes very accurate and straight barrels, so it saves us time on our end which saves you money on machining time and finding that special load. A lot of other pre-fit barrel suppliers don’t do both steps while machining a barrel. This is why we don’t believe our pre-fit barrels are of any less quality then having your action sent to us to install your barrel.

prefit barrels IMpact precision barreled actionThere are other facts of machining that can very headspace and fitment on pre-fit barrels also. Thread pitch diameters need to be measured during the threading process. This ensures repeatable proper fitment of the barrel’s threads versus the threads of the action. You don’t want threads that are too tight, and you don’t want them too loose either. You will notice that the action should have a nice solid fitment against the thread tenons shoulder. Which you will see and hear a solid shoulder to face engagement of this when the pitch diameter of threads is properly sized. And you will also notice when the action is torqued on it will only move slightly in rotation before torque setting is reached. This indicates properly sized threads with face to face engagement.


Alright, let’s talk about the action companies we use to make this all possible. We truly believe in these companies and their amazing dedication to quality and craftsmanship. All of these companies are listed in no particular order just showing the benefits we have seen.


prefit barrels Impact Precision 737R Action

Impact Precision owned and operated by Tate Streater who makes one of the most consistent actions on the market today. Its quality and precision are unparalleled. They are made from one solid piece of 416 steel. They have an M16 style extractor, Remington style footprint, and Remington style bolt nose with push style feeding. With their threads always orientated in the same position this ensures proper fitment every time. The headspace from action to action is +-.0005” which is amazing to see that they honestly are slightly tighter than this spec from our measuring history. Also, Tate and his crew of perfectionists take this to a whole other extreme by measuring all the key aspects of their actions and documenting it per serial number. That’s some serious time spent on their product. They also offer additional bolts so you can change calibers from magnum, standard .308, PPC, and 223 bolt faces they cost 450.00 but include the firing pin and all components to function right out of the box. This covers all your caliber needs. No wonder it’s the leading action in the precision rifle sports. Every time we barrel an Impact action it’s an absolute pleasure. Plus it runs in some really dirty conditions and also requires minimum maintenance.

prefit barrels for Big Horn Action

Big Horn Arms/Zermatt Arms makes several models of actions that we offer shouldered pre-fit barrels. All their actions utilize a floating head style bolt which you can replace to change from small to larger calibers utilizing the same bolt body and handle. They have control round feeding and mechanical ejection. The TL3 and SR3 are the highest-end actions they make with pre-hardened 416 steel. The less expensive Origin actions are made from Chrome Moly steel and don’t have an integral recoil lug. This makes it harder to time too than the other actions in this article. The TL3 and SR3 have a headspace tolerance of +-.0005” and recoil lug machined into the action. The Origin uses a separate recoil lug that has a tolerance of +-.0007 because of this removable lug. All models are a Remington style footprint and use Rem triggers. The extra bolt heads for these actions cost 125$ for standard .308 cartridges and down and 175$ for the magnum bolt head. All models use the same bolt heads. These are also widely used actions for pre-fitting barrels too.

prefit barrels for Defiance Machine Ruckus Action

Defiance Machine has jumped in on quality made actions for pre-fitting barrels too. They offer several actions that we can pre-fit barrels for. The Ruckus is the new heavy-duty tactical action built from one solid piece of steel with an integrated picatinny rail and recoil lug. The anTi is one of the newest added actions, also made to the same specs as the Ruckus but made for hunting at a very reduced weight for packability and is made with 416 steel and compares in weight to titanium actions. The Tenacity is Defiance’s more budget-minded action that also shares these specs and can receive pre-fit barrels. All these models are Remington style footprint actions with M16 style extractors and push feeding. They guarantee +/-.001 headspace which is looser than the other companies but we feel it’s adequate for proper headspacing with their steel qualities always being top-notch and having great wear factors and hardness.  

prefit barrels for Lone Peak Arms Fuzion Action

Lone Peak Arms also builds a nice competition action that we offer barrels for. We only offer barrels for their Fuzion Short action 416R stainless steel action. The older models and titanium actions do not have timed threads and vary more on headspacing so please be aware that serial number FZ1085 and above all have the timed threads for pre-fit barrels and headspace tolerances will be on. They have stepped up to the challenge with their actions having very tight tolerances on headspace. They also hold a +/-.001 headspace and with a Rockwell hardening of 40, they will last a very long time. Their features include M16 style extractor, plunger style ejector, Remington 700 footprint, and push feeding. They run great in dirty conditions and require little to no maintenance.  They also offer additional bolts in .223, PPC, .308, and Magnum bolt faces so you can switch calibers with different barrels. They cost 350$ but only include the bolt and handle for this price. So, you have a little time switching the firing pin and other essentials over.


prefit barrel installation

In conclusion, any of the actions you see listed on Blue Mountain Precision online store for pre-fit options means we have tested and checked them for quality and consistency so we can couple them with great, super-accurate barrels and with just a barrel vise and torque wrench you can change out your own barrels at home. Don’t hesitate to email or call us on any additional information you might need to get your next project underway.



Watch videos below for better understanding of pre-fit barrels.


Shoot Straight.


Customer’s feedback: 5 shots group at a 100 yards


By Eric Andersen


Blue Mountain Precision