What is “The Bellm Protocol”?

In short, it is a few basic remedial steps of enhancing the T/C single-shot system, steps that are proven to be necessary to make these guns functional and accurate. Steps we have spent the last 40 plus years perfecting with our technical articles, instructions, and cost-effective product line.

lease understand that while my website will go into much greater detail and is full of free instructions anyone can follow, this article will outline the steps YOU can take to get the most out of your T/C no matter how new or old the gun is. No advanced gunsmithing required, I will only mention the steps YOU can take in this article. But in the event you feel like this is still beyond your skillset, Bellm TC’s does offer installation services. Point is, you don’t have to suffer sub-par results from your T/C if you apply these simple steps.

The exposed breech, interchangeable barrel, break open guns are in fact very different from other guns, and they must be treated differently from bolt action, semi-auto, or fixed barrel guns. 

Every shooting system is a system of dynamics that must all work together to produce a consistent repeatable result each and every time you pull the trigger, aka accuracy. Way too often, otherwise proficient, shooters will fail to respect the inherent benefits of an exposed breech interchangeable barrel system way before realizing its full potential. In a world where the word TACTICAL put in front of or in the description of just about any product drives sales, we understand a single shot is not for everyone. But it is for you and me, so let's talk about HOW to make the system work its best for YOU.

Every shooting system requires its own set of basic remedial procedures to make it work to it’s fullest potential. The goal of accurizing any system is to address all known flaws and narrow down it’s potential to a final variable being the loaded round you are shooting AND the person behind the gun pulling the trigger. I can’t take you by the hand and turn you into a crack shot overnight, that would take time and a lot of practical experience behind the trigger. Even the best training and fundamental shooting practices degrade with time. Only you can do a check-up from the neck up to your own shooting proficiency.

I can take you by the hand and show you the simple steps YOU CAN DO to make your T/C shoot to it’s fullest potential. That said, the Contender and Encore is no different from other guns in the respect that they come in a box and are far from perfect, to begin with. Buried beneath the surface, is a fantastic trigger and excellent accuracy potential. Couple that with the ability to easily address flaws, accurize the system, the more economical T/C shooting system is an excellent foundation to make better through a very simple and economical set of procedures, and BELLM TCs is the company to help you.


You would not accept a bolt action that has a barrel that shakes and moves on the receiver, so why on earth would you expect a loose-fitting barrel to shoot its best on a break-open gun?

Using a hinge pin that is an interference fit at the barrel lug and on each side of the frame is the only solution we have. While others have attempted to perfect the fit of the pin to the frame and the barrel, the other “accuracy pins” on the market are in fact a complete waste of time. 

One simply pinches the “ears” or sides of the pin tighter against the frame, the other expands one end of the pin tightening its fit on one side of the frame which actually causes damage to frames by loosening the fit on the side of the frame. Neither do anything to address the tolerance over the entire length of the pin providing a tolerant fit at the lug AND at both sides of the frame. 

A "one size fits and corrects all" is not a practical answer to the problem so we have designed our hinge pins to cover the broadest range of hole diameters AND we use a manufacturing process that produces a smooth bearing type surface across the entire length of the pin

Included with every pin and throughout our website are simple to install instructions that anyone can do to see immediate benefits on paper and without having to drill, ream, or modify the frame, barrel lug, or forend to use. Our quality hinge pins are available in 2 sizes for the Contender/G2 and 4 sizes for the Encore/Prohunter.

The fact is, the barrel of a single shot is never going to be as tight of a fit to the receiver as a bolt action or semi-auto where the barrel is threaded to the receiver. But there is a lot more to the concern than just the design of the gun. The Contender’s locking bolts of the barrel must lockup to the point the interlock is turning to the side allowing the hammer block safety to fall freely, Encore and G2 require the barrel's locking bolts to push the interlock back enough to allow the sear to engage to the hammer. 

There are functional, and certainly safety, concerns of how the barrels locking bolts engage to the table of the frame, the rounds headspace or lack of can cause even more concern (more on that later).

A tight barrel lockup is paramount to an accurate system. We have designed our HD LOCKING BOLT springs to allow a noticeable difference in barrel lock up that you can actually hear when closing the barrel. They force the locking bolts under the table of the frame and are designed to be shorter allowing the bolts to easily collapse when opening without munching the spring under compression.

A simple self install anyone can do with common tools, the BELLM TCs HD locking bolt spring will make a noticeable difference to the function and accuracy of the system, you can actually hear the difference!


I will never forget the hours spent during basic training under the hot Georgia sun dry firing the M16 with the dime on the end of the barrel, the goal of the lesson was to learn the muscle memory of pulling the trigger without letting the dime fall off. I remember thinking to myself if I only had the CRISP custom-tuned trigger of my Contender this would be a piece of cake to master but soon realized that no matter how much time was spent establishing the muscle memory that would soon be forgotten especially under pressure. 

Being able to accurately shoot a heavy, gritty trigger is a skill-set few will master and is better addressed by lightening the weight of pull and reducing the felt friction of the pull, ie creep. Even though I went on to make my own “snap caps” and practice until I felt more at home with heavy triggers, I’ve also spent hundreds of dollars on drop-in triggers knowing that there are battles I just can’t win when it matters most.

Luckily the T/C single shots are very easy to work on and can have some of the smoothest triggers of any firearm made once the required smoothing up is done and a quality performance spring kit is installed. We manufacture and sell springs for all generations.

Contenders which actually had a fairly adjustable trigger, to begin with, and with our new springs and instructions are very simple to install to make better. Requires common tools to install but does have a specific set of instructions which we have for free on the website, install instructions can also be found under every springs product listing.

The Encore and G2 are a little different story, there is no adjustment "per se" of the trigger to striker engagement like on the Contender. One size fits all again doesn’t apply here, some prefer a heavy pull for hunting, and others prefer a lighter pull for controlled shooting environments.

That is why we designed our springs differently and we make 7 different sear springs pull weights for the sake of fine-tuning, #1 through #7. The numbers go in reverse order of pull weight, the #1 is the least amount of reduction from a factory pull weight and the #7 is the most amount of reduction and should be reserved for fine-tuning only. 

Encore and G2’s trigger job is a simple BELLM TCs spring kit install and can be done with common tools for most pull weights above 2lbs, with few exceptions. Our custom sear spring assembly pliers really help to get the sear spring into position and applying enough compression to get the assembly pin through. And if going below 2lbs of pull or just prefer the best possible results we do have a custom sear hone and polishing stones that can be used to smooth up the sear and raise the sear notch angle for increased engagement to the hammer.

With that said, our #3 spring kit for Encore or G2 is our most popular and is almost always a simple drop-in kit.


Lock time and reliable ignition are critical to accuracy and even having a round fire at all. The OEM hammer springs are minimally up to the job of lighting primers, especially hard primers. If you have excess headspace, shorten the hammer spring, 

and to make it rebound reliably to half cock in conjunction with a lighter trigger/sear spring, add weight to the hammer with a hammer extension which the factory condemns the use of for said reason, or are shooting hard to light primers, you must use a heavier hammer spring.

 And a heavier hammer spring speeds up lock time and ensures a hard impact of the firing pin to primer. Included in every G2 or Encore spring kit is a BELLM TCs heavy hammer spring. 

Available in two different strengths, our #44 hammer spring will be in all spring kits above 2.5 lbs and is generally our recommended spring unless going below 2lbs of the trigger pull or using a hard military primer or shooting rimfire. 

 The Contender hammer spring as mentioned in a previous article is under constant strain and simply should be replaced periodically. Speaking of hammer extensions,

 in spite of what the factory says, they are essential for getting a positive, safe “purchase” on the hammer cocking it. However, the Encore’s hammer is of a rather frail design.  The waist of the hammer in front of the spur is very thin and will often break off, especially if a heavy steel hammer extension is used and/or the gun is dry-fired much. 

The impact of the hammer hitting the back of the frame tends to bend the spur up and forward until it breaks off.  Over-tightening the set screw trying to keep the extension from sliding forward can also result in bending the hammer spur up when it is installed on the right side of the hammer, 

and we have seen spurs bent downward also when installed on the left side.  

 The bottom line regarding hammer extensions: Go light. 

Use aluminum, not steel. Use a design that stops the extension from sliding forward by some other means than just set screw pressure on the side of the hammer, as the vast majority of those on the market do.


These guns are different from bolt actions, notice how the head of the case is NOT held tight against the bolt face and is only collapsed into the chamber by the bolt face. 

 It’s not until the firing pin impacts the primer will the round find it’s true headspace. Then upon ignition, the case will expand into whatever GAP it has to fill, ie fire forming. What works with sterling success in bolt guns can be poison to success with the break open guns.  

 Cases too short, ie, excess headspace, ruin accuracy mostly due to the erratic ignition created by having to drive the case forward in the chamber before it comes to a stop and the firing pin does its work. Likewise, cases that stick out too far will interfere with;

 A) complete lockup of the barrel in the frame and 

B) put an inconsistent preload on the frame on a vertical plane that often rears its ugly head in the form of vertical stringing of shots. Need I tell this audience that ammo that fits right tends to work right? But, what works in bolt guns whose breech faces are in line with the axis of the bore and whose great camming power is a real plus with positive pressure on the bolt face does not apply in the break open guns.

 With these break open guns, light loads and neck sizing or partial full-length sizing will work for some folks some of the time, but more often than not produces problems.  Thus, 

if someone says they are not able to cock the hammer or are getting vertical stringing of shots, my tendency is to treat them like a red-headed stepson and first ask, “OK. What is your barrel-to-frame gap?” If they cannot answer that question, then they have no clue what their headspace is, either plus or minus. I recommend the headspace be kept as close to zero as possible without the breech face applying any force to the case while closing the barrel. Said another way, shoot for .001” actual headspace, .003" maximum. 

There are several ways to go about this, the best of which is to simply add or subtract how much the case head sits below or above the end of the barrel to the actual gap measurement, 

as determined with a common feeler gauge set. Where the case head stops relative to the end of the barrel is measured with the barrel OFF the frame, once the barrel-to-frame gap is established. 

 Everyone shooting break open guns will sooner or later find that solutions to unavoidable problems come from understanding and managing headspace, and thus FULL-LENGTH size die adjustment, to produce the correct shoulder to head dimension and thus the correct distance from the head to the breech face Measurements must be taken, and the most precise/easiest way to take those measurements is with the Bellm Headspace Indicator, instructions for which are on our online store.

A depth micrometer can also be used for this purpose but after 26 years of juggling depth micrometers on case heads,

 my depth micrometer now has a nearly permanent home in the drawer and seldom sees the light of day. My Headspace Indicator is all I use for determining headspace and cutting chambers to the correct depth to get that headspace. It also makes error-inducing comparators and bullet seating depth gadgets just that, gadgets, expensive and cumbersome gadgets at that. 

The barrel itself is “the gauge.” You take your measurements directly from it with the indicator. Short course on determining bullet-to-rifling contact point and distance to breech face: Size your cases to produce .001” headspace. 

Seat a bullet long so the case sticks out of the chamber more than what produces .001” headspace, then tweak the bullet deeper into the case until the case head returns to its empty case only amount of protrusion from the end of the barrel. 

You will now have EXACTLY produced the throat contact to breech face dimension IN YOUR BARREL. No variances due to bullet shape or shape on the ends of the rifling compared to a “comparator.” 

 "Correct headspace is essential to accuracy, reliable functioning, and a good case life!" Make sure you check out our article on Headspace | How To Get It Right to learn how to measure, make corrections, and also measure throat length!


I’ll never understand why guys are hell-bent on obtaining muzzle velocity better suited for other rounds and guns. As previously mentioned this is a different weapon, it’s strengths and weaknesses are different.

 The fact of the matter is that this weapon will NOT usually respond in a positive manner to hot loads and if it does you can bet case life will suffer AND when loading for the vintage Contender where some replacement parts are no longer available is asking to make your beloved Contender into a paperweight. Hotter is not better and often times it can be a recipe for disaster if you don’t appreciate the strong differences of this weapon. 

 In all my years of reloading for the T/C, I can’t think of a single load where the gun grouped better at the upper end of the load scale. So through a lot of trial and error, and yes I learn from my mistakes and I hope to prevent you from experiencing some agony and frustration, I avoid the upper end of any load scale like I avoid exposing myself to COVID 19. 

Anyone that relies wholeheartedly on load data is a fool without taking into consideration the platform you are shooting.  If the test rifle is NOT a T/C single shot then that data MUST be adjusted up or down accordingly.  A perfect example is .223 Remington most books have a test rifle that is NOT a Contender and is most often a bolt action or semi-auto, therefore if I’m loading for a Contender I’m going to reduce that data a substantial amount, a G2 a moderate amount, and if loading for an Encore/Prohunter a slight amount. 

Through a lot of trial and error, I’ve established a percentage reduction of start and never exceed per platform and while not a proven science this does keep me in a safe zone for the weapon I’m loading for. So a very safe place to start is a 15% reduction for the Contender, 10% for the G2, and 5% for the Encore/Prohunter. That is a percentage reduction of the published start and never exceed charge.  Often times 

it's the median of the adjusted start and never exceeds that I find the best case life and consistent point of impact. Not a proven science but certainly how I’ve learned to adjust load data based on the strength and design differences. On another topic, you cannot rely on the PRIMER as a pressure indicator like on other guns where the head of the case is held tight against the bolt face.

 Due to the design of the gun and how the case is being driven forward by the impact of the firing pin, the primer will show different pressure signs. What you can and should do is learn to record and measure HEADSPACE of the loaded vs fired round. Knowing how much the case is stretching/fire forming is an excellent way to monitor pressure. And for those that don’t hand load, just avoid any hot loaded factory rounds. 

 If the manufacture advertises higher velocity then other rounds, choose a box that doesn’t. With that said even you can use Step 4 to at least check the measurements of the factory ammo AND make adjustments to headspace using our headspace shims. 

And if you do have any interest in handloading, the Thompson Center is the ideal platform to learn on. Many of the mistakes being made learning to reload would be avoided IF they had simply learned to reload on a single shot. Having an exposed breech is a huge benefit to learning the proper way to size your brass and the BELLM indicator base and dial indicator should be in everyone's T/C toolbox.


You would think that proper firearms maintenance is something everyone would naturally practice but the truth of the matter is that I see way too often the worse case scenarios.

 While I hope this audience is more in tuned than the average shooter to firearms maintenance, way too often we fail to take the proper steps to clean all the components of the gun AND periodically replace springs and components that wear over time. My wife hates it that every time we shoot the guns are cleaned way before any other chores are considered, but after 24 years she accepts it. 

I take pride in knowing how all my guns function and I believe that every firearm should be completely stripped and cleaned on a frequent if not every use basis. Luckily your T/C is one of the easiest firearms you will ever own to maintain. is full of free downloadable instructions and our springs are a cost-effective way to keep your T/C operating better then it should for years to come.

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