HK Registered Trigger Housing and Roller Sear

Machineguntony · November 3, 2014, 08:44 PM

Some people swear that the roller sears provide for a smoother action, and thus a trigger action that is as 'smooth as butter'. Others claim that the roller sear do nothing.

Does anyone have experience using the newer roller sears? I've never shot one. What improvement does this roller sear have over the older friction sear? What is it 'rolling'?

There are some who state that the roller sear does not engage the action, so thus can not affect the smoothness of the action. Wouldn't the rollers allow for less resistance in the action, and thus translate to a smoother action?

If the roller sear does nothing, why would HK make the change from the older friction sear to the newer roller sear?

Willie Lowman · November 4, 2014, 10:26 AM

Have fired HK "transferable auto sear" guns, factory presample guns with factory "friction" sears, and new HK postsample guns with the roller sear. I could not tell a difference from the trigger pull or how the gun shot.

I think HK changed the design because they thought the roller sear would be more reliable in the long run. Perhaps less prone to failure. I don't know

Machineguntony · November 4, 2014, 11:06 AM

Herein lies an inconsistency. If you search online and read information about the Flemming sears, which is a friction sear, the friction sears will last either forever or into the million of rounds because the sear sustains no pressure during the firing process. But their very name implies that they induce a bit of rubbing or at least create some friction. After so much rubbing, you are going to wear down the sear, and eventually would it not break or wear to an unusable state?

I'm sure there was a good reason HK made the change.

Willie Lowman · November 4, 2014, 01:28 PM

HK is fine German firearms engineering.

You know what they say about German engineering...

The German anvil has 16 moving parts and must be wound every half hour.

Seriously though, there are G3 rifles with the original friction type sear that have been in service for decades. I am sure that someone found some small flaw in the design and improved on it with that roller.

As far as the roller making anything smoother from the shooter's perspective; When you pull the trigger to fire the gun the bolt is closed and the hammer is clear of the sear/catch. It can't have any impact on the trigger pull that I could see.

November 3, 2014, 08:44 PM	#1
Machineguntony Senior Member Join Date: June 22, 2013 Posts: 1,277	HK Registered Trigger Housing and Roller Sear Some people swear that the roller sears provide for a smoother action, and thus a trigger action that is as 'smooth as butter'. Others claim that the roller sear do nothing. Does anyone have experience using the newer roller sears? I've never shot one. What improvement does this roller sear have over the older friction sear? What is it 'rolling'? There are some who state that the roller sear does not engage the action, so thus can not affect the smoothness of the action. Wouldn't the rollers allow for less resistance in the action, and thus translate to a smoother action? If the roller sear does nothing, why would HK make the change from the older friction sear to the newer roller sear? __________________ Sent from Motorola DynaTac 8000x Last edited by Machineguntony; November 6, 2014 at 11:32 PM.

November 4, 2014, 11:06 AM	#3
Machineguntony Senior Member Join Date: June 22, 2013 Posts: 1,277	Herein lies an inconsistency. If you search online and read information about the Flemming sears, which is a friction sear, the friction sears will last either forever or into the million of rounds because the sear sustains no pressure during the firing process. But their very name implies that they induce a bit of rubbing or at least create some friction. After so much rubbing, you are going to wear down the sear, and eventually would it not break or wear to an unusable state? I'm sure there was a good reason HK made the change. __________________ Sent from Motorola DynaTac 8000x

November 4, 2014, 10:26 AM	#2
Willie Lowman Senior Member Join Date: March 5, 2009 Location: Uh-Hi-O Posts: 3,006	Have fired HK "transferable auto sear" guns, factory presample guns with factory "friction" sears, and new HK postsample guns with the roller sear. I could not tell a difference from the trigger pull or how the gun shot. I think HK changed the design because they thought the roller sear would be more reliable in the long run. Perhaps less prone to failure. I don't know

November 4, 2014, 01:28 PM	#4
Willie Lowman Senior Member Join Date: March 5, 2009 Location: Uh-Hi-O Posts: 3,006	HK is fine German firearms engineering. You know what they say about German engineering... The German anvil has 16 moving parts and must be wound every half hour. Seriously though, there are G3 rifles with the original friction type sear that have been in service for decades. I am sure that someone found some small flaw in the design and improved on it with that roller. As far as the roller making anything smoother from the shooter's perspective; When you pull the trigger to fire the gun the bolt is closed and the hammer is clear of the sear/catch. It can't have any impact on the trigger pull that I could see.