The SierraPapa hammer upgrade is manufactured in the USA from a solid block of high grade stainless steel. After machining the hammer is polished and hardened for long life and smooth operation, and finally the sear notch is hand-polished in our own shop to provide the smoothest possible trigger release.

The hammer is engraved "SP USA" to demonstrate BATFE Part 922R compliance.

For best overall results the hammer upgrade should be installed concurrently with our adjustable metal trigger and reduced power hammer spring upgrades.

Price of hammer/trigger/spring upgrade kit: $186.50*

Shipping charge $10.50* by USPS Priority Mail

*A credit card processing fee of 3% applies to all credit card transactions. Payment by check, money order, or cash allows us to waive processing fees and keep our prices lower.

Be sure to view our warranty and terms of sale. 

The SierraPapa trigger upgrade is manufactured in the USA from 6061 grade aluminum. After machining, the trigger is anodized to provide a durable, non-reflective finish. 

This replacement trigger is stronger and less flexible than the original CX4 plastic trigger, and features an adjustment screw that removes much of the objectionable pre-travel found in the original trigger group. The new trigger also features a permanently installed pivot pin for attachment of the first trigger operating bar. This ensures less flex in the trigger movement. Additionally, the slightly larger diameter of this fixed pivot pin removes some of the slack in the trigger movement.

The trigger is engraved "SP USA" to demonstrate BATFE Part 922R compliance.

For best overall results the trigger upgrade should be installed concurrently with our stainless steel hammer and reduced power hammer spring upgrades.

Price of hammer/trigger/spring upgrade kit: $186.50*

Shipping Charge $10.50* by USPS Priority Mail.

*A credit card processing fee of 3% applies to all credit card transactions. Payment by check, money order, or cash allows us to waive processing fees and keep our prices lower.

Be sure to view our warranty and terms of sale.

SierraPapa reduced power hammer springs are manufactured in the USA from high grade spring steel. The new hammer springs are offered in two weights: light and medium. The light-weight spring provides the lowest trigger pull weight and it has been tested with complete reliability, using standard ammunition, in our test rifles. Theoretically there exists ammunition with "harder" primers. Our medium-weight trigger is an option for those who value ignition reliability with all possible ammunition types or who simply prefer a more positive trigger action in a combat carbine.

The reduced power hammer springs should only be used with our stainless steel hammer modification. Installing the reduced power hammer springs with the original CX4 plastic hammer may result in unreliable firing pin operation. The lighter weight of this spring causes it to be relatively more susceptible to the influence of each part of your CX4 when measuring trigger pull weight. 

For best overall results the reduced power hammer spring should be installed concurrently with our trigger and hammer upgrades.

Price of hammer/trigger/spring upgrade kit: $186.50*

Shipping charge: $10.50* USPS Priority Mail

*A credit card processing fee of 3% applies to all credit card transactions. Payment by check, money order, or cash allows us to waive processing fees and keep our prices lower.

Be sure to view our warranty and terms of sale.

We began to notice mid-2013 that newer CX4 rifles were arriving on the market with slightly varying trigger housing lengths. Some of the longer housings require an additional element in our Trigger Kit to ensure a good fit. This additional element is the Sear Clip. Not only does it effectively shorten the length of the trigger housing, but it provides a metal surface for the sear of our metal hammer to act against. Durability of the housing is thus increased, and customers also report a smoother action when the gun fires. 

The clip is made by our custom springmaker of specially hardened steel just a few ten-thousandths of an inch thick. It clips neatly over the edge of the housing, and is held securely in place by the fit of the housing in the lower.  

Please note that this part may or may not be required in your CX4. The necessity or otherwise of its use will be made in our shop as we judge the fit of our parts in your housing. If you have any questions about this, please call us at (503) 621-3017.

WE DO NOT RECOMMEND INSTALLATION OF THE SEAR CLIP FOR ANY PURPOSE OTHER THAN IMPROVING THE FIT OF YOUR HAMMER. If the sear clip is not required specifically to shorten housing length, its installation will interfere with the smooth action of your hammer and worsen the feel of the trigger pull. One sear clip is included with each hammer/trigger/spring kit.

SierraPapa's newest product is the Machined Aluminum Trigger Housing. Engineered specifically to work with the SierraPapa Hammer/Trigger/Spring Kit, the Housing is machined in our own shop from a solid block of 6061 aluminum, then hard-anodized for durability. A 1/8" hardened steel sear is inserted to provide metal-on-metal contact at the critical sear face. The addition of a second point of trigger adjustment permits the removal of all over-travel and almost all pre-travel, and trigger pull weight is reduced to an anticipated 4.5 lbs. The trigger feel is clean, crisp and predictable, round after round.

Many CX4 owners considering the Machined Aluminum Trigger Housing upgrade will already use the Hammer/Trigger/Spring upgrade. Owners of these parts can continue to use them in the new Housing. (Please note that the Machined Aluminum Trigger Housing cannot be used with the stock Beretta hammer and trigger.)

We will need your entire lower to install the Aluminum Trigger Housing. An economical shipping option is to  use one of the USPS large, flat-rate, priority mail board game boxes (24" long). The CX4 can be broken into the upper and lower, and the lower packed inside this box. Shipping to SierraPapa is $18.90 and includes tracking. Insurance and signature confirmation may be purchased separately. 

Price: $350.00*, installed and tested in your CX4 (does not include cost of Hammer/Trigger/Spring Kit).

Hammer/Trigger/Spring Kit purchased separately: $186.50*

Return shipping charge $29.85* by USPS Priority Mail. Please let us know if you would like additional insurance or other shipping services. We reccomend insuring the package for a minimum of $1000. 

*A credit card processing fee of 3% applies to all credit card transactions. Payment by check, money order, or cash allows us to waive processing fees and keep our prices lower.

Be sure to view our warranty and terms of sale.

For everyone who has ever scraped their knuckles on rail accessories while charging the bolt on their CX4, SierraPapa manufactures a solid steel extended charging handle. The handle and pin is machined in one piece, so that the pin will never separate from the handle, and then treated with an iron oxide finish to match the rest of your rifle. 

The greater distance from rifle to handle allows the force of pull to be exerted in a more natural, ergonomically appropriate line with the arm and shoulder, as the shooter no longer needs to cramp his or her arm up to the rifle, and the smooth curve of the handle comfortably accommodates the shape of the fingers.

Price: $67.50*

Shipping charge $10.50* by USPS Priority Mail

*A credit card processing fee of 3% applies to all credit card transactions. Payment by check, money order, or cash allows us to waive processing fees and keep our prices lower.

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The SierraPapa Steel Guide Rod replaces the stock plastic guide rod with an unbreakable steel rod, and guarantees absolutely reliable function of this critical part. Improved push-fit attachment to the plastic buffer reduces assembly/disassembly damage, and the recoil spring conveniently stays in position on the guide rod for cleaning and disassembly of the bolt group.

This Steel Guide Rod uses our High Durability Buffer for longer buffer life and improved performance, and accepts our bronze Bolt to Recoil Spring Link for life-long reliability.

Price of Steel Guide Rod Kit (includes Rod, HD Buffer, Bronze Link): $87.50*

Shipping charge: $10.50* USPS Priority Mail

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This is our upgraded Bolt to Recoil Spring Link.

There may be more interesting-looking objects to photograph, but this part is an essential item in ensuring the reliability of your CX4.

If the original plastic part fails, you do not have even a single-shot carbine and the gun is totally disabled. This upgraded part is made of bronze and it will last forever. As many of you may know, the use of bronze in firearms reaches back to the first firearms ever produced because the metal is so tough and corrosion resistant.

This part is very simply installed and is included with our steel guide-rod kit upgrade.

Steel Guide Rod, HD Buffer, Bronze Link kit: $87.50*

Shipping charge: $10.50* USPS Priority Mail

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Our High Durability Guide Rod Buffer is now available. This buffer works only with our steel recoil guide rod modification.

The recessed shoulder around the guide rod hole has been made level with the rest of the buffer body increasing the area available to absorb the shock of the bolt impact during recoil. The through hole for attaching the guide rod is no longer required so this has been removed once again increasing the area available to absorb the shock of bolt impact during recoil.

This HD buffer is produced from a resin designed especially for uses involving high levels of impact and abrasion (the material is used in the mining industry to protect metal parts from abrasion). The material is cast in a mold after mixing two liquid compounds rather than being produced by injection molding of heated plastic. The use of two part resins permits a much wider selection of "mixes" to tailor the material to its intended use as opposed to the fairly narrow range of material choices provided by heat-injected plastics.

Price individually: $12.50* (required with our steel guide rod). 

Price of Steel Guide Rod, HD Buffer, Bronze Link kit: $87.50*

Shipping charge: $10.50* USPS Priority Mail

*A credit card processing fee of 3% applies to all credit card transactions. Payment by check, money order, or cash allows us to waive processing fees and keep our prices lower.

Be sure to view our warranty and terms of sale.

SierraPapa is now offering a conversion that many of you have asked about after seeing our own modded CX4 on our home page. The Collapsible Buttstock Conversion removes your factory buttstock, adds a right/left sling mount, and prepares it for replacement with the AR-style buttstock of your choice. (Please note you must supply your own buffer tube and buttstock to us. We cannot ship firearms that do not have the new tube and stock installed.) Customers can choose from 6 different overall rifle lengths with the adjustable stock for an optimized shooting experience.

The process of conversion is as follows: Upon receiving your rifle's lower assembly, the factory stock is removed and the lower is placed in the jig of our CNC mill. The center of the lower is determined, and a cavity is milled out and then filled with a threaded aluminum plug. After a 24hr curing period, the lower is placed back on the mill for sizing and threading. Finally, the buffer tube and adapter plate (featuring two sling mounts) are installed, and the work is inspected. 

Please make sure you include your buttstock, buffer tube, and accompanying lock nut in the box when you send us your rifle, or that you have it shipped to us directly from the supplier. We cannot proceed with your conversion until we receive the new stock, tube, and nut. Please call us at (503) 621-3017 if you have questions about suitable stocks and tubes.

Price for Collapsible Buttstock Conversion: $195.00*

SHIPPING YOUR CX4 TO SIERRAPAPA

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SierraPapa now offers the flat top conversion we performed on our own CX4 (pictured on the Home page and to the right), in response to the demand from so many customers.

This modification includes removal of the "ears" and milling of the upper surface completely flat and smooth. During this process, the cavities that lie under the ears are exposed, and filled at the front cavity with a milled aluminum block, to provide a sturdy anchor for one of the two added rail screws, and at the back with a milled black nylon block, to blend with the rifle body. The front aluminum block is covered by the extended flat top rail, and the rear black nylon block remains visible. The stock white nylon block under the front ear, present in your rifle as you received it from Beretta, will be exposed and remain partly visible after this modification is performed. Part of it will be obscured by the rail-- please see the pictures on this page.

Included in the cost of conversion is the black-anodized aluminum, 14" picatinny rail we designed and custom-machine specifically for the CX4. Its groove accommodates the seams of the CX4, and the longer length (14" as opposed to the stock 10 7/8") permits the shooter to affix a diverse range of accessories.

Price for complete Flat Top Modification and 14" Top Rail: $390.00*

We do NOT need your lower to perform this mod.

SHIPPING YOUR CX4 TO SIERRAPAPA

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SierraPapa has discovered a source for a limited number of rail attachment screws. These screws are made in the USA and they are an exact high-quality replacement for the original parts in fit and finish.

Price individually : $5.50*

Shipping charge: $10.50* USPS Priority Mail

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SierraPapa offers two options in high-capacity 45 ACP magazines. The Complete Extended Magazine includes our extension body and a modified Beretta 8045 mag from our own stock, and the Magazine Extension Kit adds our extension body to the 8045 magazine you supply for modification in our shop. Either option provides you a high-quality magazine extension proven to supply absolute reliability. 

The supplied parts (photograph at right) include a new black-anodized aluminum magazine extension body to extend the original steel mag, two new custom-designed springs and a plastic spring alignment spacer. The unit is designed to allow reversion to the original 8 round magazine if required. Both options require a very minor modification to your magwell insert. Please read more here about magazine modification (we do this) and magwell insert modification (you do this). 

Price of 16-rd Magazine Extension Kit: $125.00*

Price of 15-rd. Magazine Extension Kit: $130.00*

Price of conversion of your 8045 mag to accept higher capacity: $20.00*

This includes magazine extension body and plates, two custom-made springs, and black nylon slider. The 15-rd. Magazine Extension Kit includes a "limiter" that brings your high-cap mag into local compliance. 

Price of 16-rd Complete Extended Magazine: $175.00*

Price of 15-rd Complete Extended Magazine: $180.00*

The Complete Extended Magazines include all Kit parts, plus a modified Beretta 8045 mag from our own stock.

Shipping Charge $19.80* by USPS Priority Mail.

*A credit card processing fee of 3% applies to all credit card transactions. Payment by check, money order, or cash allows us to waive processing fees and keep our prices lower.

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This magazine adapter is the only product on the market that will permit the use of a PX4 .45 ACP mag in the CX4 .45 magwell. While SierraPapa is known for providing metal replacements for plastic stock CX4 parts, there are times when plastic is the right material to use. In the case of this mag adapter, 3D PLA printing produced a thin, flexible, but sturdy adapter that hooks securely into your mag well and drops the mag out freely when the accompanying mag release button is pressed. The optional SP release button is slightly longer than the stock button, and its increased length and grippy surface improve feel and function over the shorter, more slippery stock part.

8045 mags can be very difficult to come by, and this PX4 magwell adapter adds flexibility to your CX4 45 set up and is especially suited to those who already own a PX4 45. Those who want to increase the capacity of their 8045 CX4 mags to 16 or 15 rounds should consider our CX4 magazine extension.

PLEASE NOTE: The adapter and release button may be used together, but your stock 8045 mag release button may also be used. 

Price for the adapter/mag release button kit: $88.00*

Price for the magwell adapter only: $61.50*

Price for the mag release button only: $26.50*

Shipping charge $10.50* by USPS Priority Mail

*A credit card processing fee of 3% applies to all credit card transactions. Payment by check, money order, or cash allows us to waive processing fees and keep our prices lower.

Be sure to view our warranty and terms of sale.