The proportions, curves and profiles of traditional revolvers have a visceral appeal that makes for a classic and timeless design.  With most, if not all, mechanical designs form usually follows function, however with the revolver form and aesthetics play a leading role.  We simply cannot stray far from the lines of the traditional revolver.  That criteria poses serious challenges to designers who seek new revolver layouts.  Revolvers to date have differed from their semi-automatic brethren in that their mechanisms have been of traditional single-action (SA) and/or double-action (DA) operation.  This differentiates the revolver from the traditional magazine-fed, semi-automatic pistol.  Specifically with regards to accurate follow-up shots and rate of fire.  Single-action revolvers offer great trigger pulls but are let down by a lower firing rate while the double-action variant alters the aim point during compression of the main spring.  Proficiency with revolvers is possible of course but only after much practice, usually by competition shooters.  Another weak point of the revolver is the absence of a recoil compensating mechanism like that found on the semi-automatic pistols whose mechanism offers reaction forces on the frame of the gun that help tame recoil to a degree.  This translates into a recoil impulse that generates added muzzle-flip which is then exacerbated by a higher torque moment due to the usually lower purchase on the gun as a result of the space required above the trigger where the cylinder-stop mechanism is usually housed.  These design challenges have pushed most military and law-enforcement personnel to opt for semi-automatic pistol designs.  In the revolvers favor is a simplicity and robustness of design which allow for stout cartridges to be fired, an important advantage.  Another strength of the revolver is its reliability as there are no magazine feeding issues to contend with.

While there have been attempts to ¨civilize¨ the revolver with modern, semi-automatic operation by a few manufacturers the results have all broken the cardinal rule of revolver aesthetic design as all are less than elegant, to say the least.  Some designs have seen mechanical success by inverting the barrel so as to fire from the 6 O´clock position thereby doing away with muzzle-flip and straightening out the recoil impulse but have sacrificed elegance in the process.  This approach does offer some tactical advantages albeit limiting commercial appeal.  All in all, the revolver offers pros and cons to shooters who are still in search of the best of all worlds, so to speak.

Taking these current limitations into consideration  RAFAEL LASTRA Engineering has defined the next-generation semi-automatic revolver that fulfills the strict criterion demanded in a paradigm-shifting design whose merits pave the way for new applications.  This design will have revolver fans falling in love all over again while giving pistol fans new pretenders for their shooting passions.

This ground-breaking design employs a short-stroke, gas-operated piston housed between the barrel and the top rib.  The piston pushes backwards into the shooter thereby generating a reaction force on the frame which helps mitigate recoil as in pistol designs.  This feature is optimized by being above the barrel as its greater torque moment is employed to maximum effect.  While this feature cannot completely negate recoil it will offer approximately a 20-25% reduction which in turn will alleviate muzzle-flip.  The design operates under the following principle:  Upon firing, gas pressure is fed into a chamber that compresses a spring biased piston-assembly that is connected to the cylinder locking lug usually found below the cylinder.  The piston assembly is better defined as a compound-spool assembly that is in contact with the bias spring on either side.  This design feature is mandatory as having a piston acting directly on the cylinder would provide violent actuation that would accelerate wear and would soon fracture the cylinder locking lug due to the excessive bending load it would experience.  The bias spring acts as a buffer which is first compressed and subsequently released at the given spring rate.  This means that we can control the amount of force applied to the cylinder to minimize wear and bending loads.  While this is happening, the second spool would be acting directly on top of the hammer first pushing it out of contact with the primer (allowing the cylinder to rotate) and subsequently cocking the hammer onto its sear where it will wait for a single-action pull from the shooter for the next shot.  Once the main piston has reached its maximum stroke the gas pressure is vented to atmosphere in an upward direction which allows the return spring to move the assembly forward again providing lock-up for the cylinder.  At this point the revolver will have a new round/chamber waiting to be fired with the hammer cocked and ready for the next pull.

Apart from the sequential operation provided by this mechanism required for unlocking, cylinder rotation, hammer-cocking and cylinder locking the design offers the functionality of having the mechanism cycle (racking) by pulling back on the trigger with your thumb to set up a single-action shot or having the hammer come back by pulling the trigger with your trigger (index) finger in traditional dual-action mode all in one design.  The result is a SA/DA, Semi-Automatic revolver with a recoil compensating piston that allows for a higher purchase on the weapon by way of moving the trigger-guard up between 4-5mm as the locking lug is now found on top of the cylinder and not the bottom as in traditional designs.  This higher purchase on the gun means that recoil is easier to control by way of the reduction in the torque moment imposed.  That feature coupled with the short-stroke piston pushing back towards the shooter would add up to a reduction in recoil of approximately 20-25% along with a muzzle-flip reduction of approximately 50-60%.  All of this is done offering SA/DA Semi-Automatic functionality.  Functionality that only requires an extra 3-4mm of material above the top rib of current designs (which does not add muzzle-flip as the barrel axis does not move) while cutting out 4-5mm of height above the trigger guard.  Not only does this design maintain the elegant proportions of the traditional revolver, it will actually improve them by shortening up the bottom portion of the frame.  It is a ´win-win´ design on all fronts that will pave the way for new applications while generating new devotees to the timeless revolver.

Another important design feature of this semi-auto revolver is the much simplified lockwork that not only uses less components to provide the usual safety functions but also offers a trigger feel in double-action mode that is superior to traditional designs.  In the first graph below we can see the general trigger force profile of standard designs.  This profile is characterized by a steadily increasing load followed by the sudden release of the hammer.  The release happens with no feedback at all to the shooter to let them know the exact point of firing.  This unpredictability causes difficulty in timing the hammer release with the motion profile of your hand as it acquires targets on-the-fly.  The end result of which are shots taken in double-action mode that leave much to be desired as a result of the poor accuracy achieved with these trigger geometries.  The Lastra Snap-Action D/A trigger geometry offers a trigger pull that is full of information regarding what is taking place and, more importantly, when.  Using innovative yet very simple geometry this new double-action mode offers a smooth and stable pull up to about 3/4 of the total travel at which point the pull force drops to a lower value similar to the ¨let-off¨ one would experience in a compound bow.  The trigger pull would then rise sharply during the final 1/16¨ of travel until the trigger literally snaps off engagement with the hammer.  This feature subconsciously gives the shooter feedback regarding where and when the shot will take place.  This enables the timing of hand-eye coordination to be synchronized greatly subsequently offering improved shooting during critical defense situations where that first shot is the most important one.  This novel feature on a revolver only requires the trigger, hammer and a disconnector, nothing else.  Three components that simplify operation and reliability while not interfering with single-action firing.  No stone left un-turned in pursuit of excellence.

 

DOUBLE-ACTION-ONLY (DAO) BATTERY

The sketch below depicts a version of the above mentioned  Lastra Snap-Action D/A trigger for double-action-only (DAO) variants.  Such designs are ideal for revolvers designated for carry purposes as no safety is required to be disengaged after drawing the weapon.  The arming of the hammer during the first three-quarters of the trigger pull acts as a safety in itself which takes you to (B) in the sketch where the transfer arm/disconnector (30) is constrained by the notched sear engagement as well as the hammer (10).  This point provides the ´wall´ feature by way of increased resistance required to move past this point.  It is here that the trigger acts as a single-action in feel as it provides feedback for the actual break and subsequent release of the hammer.  By working past the wall the transfer arm/disconnector (30) forces itself out of engagement with the sear notch on the hammer whereby contact at point (X) allows for the collapse of the now disconnector (30) thereby releasing the hammer (10) as can be seen in (D) and firing the gun.  The trigger is then released fully to return to (A) and pull for the subsequent shot.  While such schemes have been used previously dating back to the late 19th century this differs in the feedback afforded by novel snap-action geometry which provides precise information as to exactly when the sear will break.  As outlined in the previous section on this page this novel mechanism differs from existing designs which simply break cleanly offering no information whatsoever.  While this design does not offer a single-action trigger function it does provide the best of that option in the feedback so critical for timing moving targets.

The other novel design feature this mechanism provides is that of a safety notch (NOT SHOWN) allowing the revolver to be carried safely with a round in the chamber such that forward motion of the hammer by external means does not allow the hammer to strike the firing pin which can only be disengaged with the pull of the trigger.  This function is achieved with full-proof geometry ensuring a seamless transition off of the safety notch and onto the sear during the first quarter of trigger travel.  This safety notch feature makes un-commanded discharges an impossibility.  All of this Double-Action Only functionality with Single-Action sear release is achieved with only three (3) moving parts, including the trigger.  It is the combination of these two functions (DAO + safety notch) that provide an ideal lock arrangement for a revolver that can safely be handled by inexpert individuals during high stress situations when life and limb are on the line.

Note that this design can be used with firing pins of all configurations including rebounding hammers.

*** PATENT PENDING ***

This revolver mechanism is already designed, as such, with appropriate machining time available a working proof-of-concept model could be developed in less than a month from inception of the project.  The proof-of-concept will familiarize you with the mechanism and allow you to then design a working prototype which could be done in a few months time with your team or under my guidance.  Serious inquiries only please.