The K31 Left hand conversion from Swiss Products.com
I was offered a chance by Pierre St. Marie of Swiss Products.com to try out their new Left Hand Operation conversion for the Swiss K31 Carbine. We had phone calls together on his new Left Hand Operating device over the last year and the improvements made to the design.
Being a "South-Paw" the force we put on the right hand bolt handle is unlike the normal pull of a right handed shooter. Rather than a straight pull reward, we pull the handle upward and into the receiver of the firearm causing us to use undue force to operate the bolt. This is caused by us reaching over to grasp the cocking knob of the bolt.
For rapid fire use many of us will roll the rifle away from our cheek and drop the carbine off of our shoulder. This is not conducive for target shooting accuracy.
What Swiss Products.com have done is to engineer a addition to the bolts linkage that places the cocking handle on the left side of the receiver, but still allow the same force needed to unlock the bolt and cycle the action.
While this has been done in the past, the original more complex modification has been redefined and the binding problems have been resolved into a very smooth and very strong operating mechanism.
The steel used as I write this in the manufacturing of the LHO device is T-1. Strong enough to be used to stop pistol and low velocity projectiles and as such, is used for small arms targets.
The LHO is a new design and more compact compared to the original version of the Left Hand Operating devices made over the years for the Swiss rifles and carbines.
A lever is used to cam the bolt allowing it to unlock and be retracted. This cam lever is in a direct line with the bolts right hand cocking knob linkage allowing an easy unlocking of the bolt locking lugs from the receiver body.
A milled relief is made to allow the left hand operating levers arm to clear the cocking ring of the bolt.
The LHO cocking knob is large and easy to grasp with two fingers even while wearing gloves.
Cycling the bolt with the K31 mounted on my shoulder, the bolt can be safely cycled with no portion of the LHO device striking your face.
The sights are always in clear view.
A slight upwards pull to the rear on the large bolt knob is all that is needed to unlock and retract the bolt.
Mounting the LHO device to the K31 bolt could not be easier.
You remove the four Allan headed screws and remove the top plate. ( an Allan wrench is included with the LHO device)
The lower plate has been milled for the K31s right hand bolt knob and the LHO fits with just enough play to allow for individual variances between the manufactures.
You then do a visual alignment of the LHO and the side of the bolt body. Once the device is aligned you tighten the two inboard screws followed by the two outboard screws.
While the "play" in the milled receiver of the LHO device is only a fraction of an inch, aligning the LHO at an angle too far forward or to the rear makes a marked difference in the force needed to cycle the bolt smoothly. The clamping force of the four screws is very strong and when tightened properly, the LHO is not going to move from its alignment point from cycling or recoil.
I will be test firing my K31 with the LHO device this weekend after Christmas and will try to have a video of it in operation.
For more information on this LHO conversion device please contact:
swissproductsusa.com
396 Willow Glen Road
Kalispell,MT 59901
I am not affiliated with Swissproducts in any manner other than to test the new LHO bolt conversion.
Thank you.
Rapidrob.