Apex Gunsmithing
1Jul/14

Technical Review: Timney Tavor Trigger

There has been a lot of buzz about aftermarket Tavor triggers lately, and a lot of folks have written great reviews already.  Though many of them noted that the Timney design differs considerably from the factory IWI sear pack, none of the reviews focused much on the technical aspects or advantages and disadvantages of Timney's changes.  Let's get digging and do some comparing and contrasting!

Timney vs IWI

Timney vs IWI

Here's a side by side of the two units, and I wouldn't blame you for being rather confused at first glance.  They're completely different!  The hammer is similar but heavier and with a wider sear surface, the springs are completely different in weight and orientation, and really aside from the trigger bar connector sticking up you almost couldn't tell the Timney belongs to the Tavor at all.


Timney Pack

To make it a bit easier to see what's going on inside there I put color highlights on the overview:

Highly artistic color overlays!

Highly artistic color overlays!

This is an interesting comparison because in almost every way, Timney's design is derived from the AR-15, while the factory Tavor uses a floating sear.  It makes sense for a company with a long history of making exceptionally good AR-15 triggers to adapt it here, and it's been done rather brilliantly too.

If you take the AR-15 trigger and chop off the actual trigger hook, you've essentially got the Timney sear highlighted in green above.  Just like their AR triggers, the sear has an adjustment screw for engagement, which on the non-adjustable models is locked in at the factory setting.  Timney took that, reworked the hammer's sear to be more AR-like, and designed a U-shaped connector cup to attach to the sear, which is the purple component.  The disconnector, blue in the diagram, is straight out of an AR-15 in its shape and function and again has a limiting adjustment screw set at the factory.

Overall the function of the Timney unit is identical to that of an AR-15, only you would substitute your finger pulling the trigger for the Tavor's trigger bar pulling the connector.  The hammer falls, gun goes bang, bolt cycles and the disconnector hook catches the hammer and holds it until you release the trigger.  As you reset, the disconnector lets go and the sear catches the hammer on the main sear surface.


IWI Pack

Conversely, the Tavor's factory sear system is derived heavily from the M1 Carbine and FN FAL, both of which were used by IDF and law enforcement in Israel for decades.  The old M1 can still be seen in use in both its original wood-stocked form and a redesigned bullpup!  Here's what the guts look like outside of the housing:

IWI sear system, colored

IWI sear system, colored

That bright green sear shifts forward and backward, or as it's pictured here left and right.  When the hammer is caught on the sear, it pushes the sear backwards so that the blue colored tail is just above a shelf.  When the trigger is pulled, the whole connector assembly rotates forward (counter-clockwise as pictured) and that shelf bumps the sear's tail, forcing it to rotate too and give up its grip on the hammer.  The hammer falls, the bolt cycles, and that spring loaded sear jumps back forward (to the left in the picture) so that the tail is no longer over the shelf.  The sear once again catches the hammer and spring loads it backwards, but the tail bumps into the inside of the connector below the shelf, holding the sear and hammer in place until you release the trigger.  As you reset, the connector rotates back and the sear's tail clicks over that shelf, ready to fire again.


Other Differences

Speaking of resets and connectors, you might also notice that the springs differ greatly between the two kits.  Timney's kit uses coil springs underneath the sear and disconnector, while the factory IWI setup has a single coil spring on a rod for the sear and a torsion spring to reset the connector.  The latter spring is pictured above on top of the connector housing, and is what I call the primary return spring or the connector spring.  IWI added the second return spring later on, which is the small pull-type spring you can safely remove to reduce the trigger weight.

It's interesting to note that while the Timney unit has a locked in adjustment for sear engagement, the factory IWI plastic housing has a stud molded into it to serve a similar purpose.  It would not be especially difficult to drill out that stud and thread in a set screw to provide adjustment for the sear.  If IWI begins selling trigger packs for replacement parts I'll experiment further on that and post about it.

Both hammers and housings have built in over-travel stops for the hammer when struck by the bolt carrier, but they're in different places.  The Timney unit stops hard on the flat back of the "tines" on the hammer against a shelf inside the aluminum housing.  The IWI hammer stops hard on the smaller "tines" of the factory hammer against a hump in the plastic housing.

For those curious, I'm almost completely certain the Timney unit uses a standard AR-15 hammer spring (reduced power) and could be swapped for a heavier Wolff extra power spring if the 4-pound pull is too light.  I may do that at some point, because personally I consider 4 pounds to be entirely too light for a defense or combat type rifle like the Tavor.


The Verdict

Timney did a stellar job adapting their expertise in AR-15 triggers to the Tavor.  Despite growing pains and a price that's difficult for many to justify, they've impressed me on every level with the trigger pack and it irks me that I've been unable to get more range time with it so far.  I look forward to seeing what else they do with the Tavor or if they can put out some budget-oriented components to fit the factory housing in the future.  At the very least, I would expect a fully adjustable unit down the road along with some revisions to the current kit as it evolves.

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