Walther Conversion Barrels2021-04-28T22:36:49-06:00


The first and only .40 S&W to 9MM conversion for the Walther P99 and PPQ 40.  Over two years ago, we developed our Walther Conversion barrel. Since then, we have received nothing but positive feedback from our customers.  Designed for ease of use and reliability, our Walther Conversion barrel simply requires the swap of a barrel and magazine. No other parts necessary.

Whether you want the ability to shoot 9MM out of your Walther 40 without the cost of purchasing another gun or you desire the versatility that the conversion offers, the Jarvis Inc Walther Conversion will meet your needs and exceed your expectations.


Walther Conversion Barrel
Walther Conversion Barrels
Walther Conversion Threaded
Walther Conversion Threaded Barrels
Alex S.
I ordered a .40 S&W to 9mm conversion barrel for my Walther P99, and it works flawlessly. The coating is slicker than the coating on my factory barrel, and it seems more accurate. My only regret is that I did not have the barrel fitted to my slide.
Ryan M.
Ordered a barrel for a 9mm PPQ. Realizing custom orders take a while, I wasn't surprised by the wait for my order. Great product. I have around 800 rounds through it within the last couple months. No issues at all.


The Jarvis 40 to 9MM Conversion for the Walther line of pistols is the first conversion of its kind.  With no part swap outs required except for the barrel and magazines, the switch from .40S&W to 9MM is quick and easy.  After thousands of rounds of testing, the conversion proved to function flawlessly and deliver the same accuracy that our barrels are known for.  For almost 40 years we have been the leader in precision and accuracy.  We do not compromise, and we demand perfection from ourselves because we believe that’s what our customers deserve.  Our extensive background in manufacturing and gunsmithing has made us the industry standard for aftermarket barrels.

What separates us from the pack?  It starts with steel.  All of our Walther conversion barrels are manufactured from 4140 Gun Barrel Certified Steel manufactured in the USA.  This carbon steel provides outstanding strength and thermal characteristics which provide phenomenal longevity and performance under thermal and tensile stresses.  Our proprietary rifling process is done by rifling machines designed by us to ensure bore and groove dimensions are held to .0005″ tolerances and do not vary over the length of the barrel.  This button rifling process produces a mirror like 4 to 6 micron finish.  Every process, from drilling and rifling, to turning and milling is carried out by our experienced machinists and gunsmiths.

At Jarvis, Inc. we believe that our experience and attention to detail are producing the finest aftermarket Walther pistol barrels available.  With honesty and integrity, we strive to serve our customers to the best of our ability on a daily basis.


The Walther 40 to 9MM Conversion Barrel is compatible with the P99, PPQ M1, and PPQ M2 40 caliber pistols in all lengths including Compact, 4″, and 5″.

The conversion requires 9MM factory magazines which are also available on our website for purchase with the conversion barrel.  Customizable options include right and left-hand threads for suppressor use, extended length, and ported options for reduced muzzle rise.


Our National Match fitted barrels provide the tightest lockup that can be achieved while maintaining the functionality of your pistol.  Fitting only requires your slide to be sent in and will not add to the lead time of your order. 

We recommend customers to select the drop in option when ordering threaded barrels for suppressor use.  The reason for this recommendation is that coupling the increase in recoiling mass of the suppressor with an extremely tight fitting barrel may result in cycling issues.  This issue can be exacerbated with the conversion as the 9MM provides less impulse than the 40 caliber round. Drop in barrels do not require fitting on any surface, they are manufactured to factory dimensions on all locking surfaces and provide outstanding function and performance.