If you’ve owned a SIG Sauer MPX for longer than about a minute, you’ve most likely heard of Robert Otte and his company In Lead We Trust.  ILWT manufactures a number of aftermarket components for a number of different platforms, but he’s an absolute Godsend for MPX owners.  He’s manufactured a variety of replacement parts which are difficult to impossible to source from SIG directly without sending in your rifle, as well as parts and components which are quite useful for those of us who run a suppressed MPX.  Beyond that, Robert is also VERY active on social media and has been a wealth of knowledge and assistance to the MPX community.  It’s extremely rare in this world to find someone who is so technically knowledgeable and capable, as well being as patient and kind.  While I was doing my recent review of the SIG MPX PCC, Robert provided invaluable technical information to me which actually corrected technical details that had been provided by SIG’s marketing folks.  It was during this time of getting to know Robert better that he offered for me to try out one of his barrels in my SIG MPX carbine.  Robert’s barrels are the stuff of legend among MPX shooters, and I was more than curious to see how it would compare to the SIG MPX PCC.

Robert sent me a 16″ barrel, which came threaded to allow for easy muzzle device attachment.  When I removed the factory MPX Carbine barrel (which features a pinned and welded flash hider) I could immediately tell there was a significant weight difference between the factory barrel and the ILWT barrel. The ILWT barrel weighs approximately a half pound less than the factory SIG MPX Carbine barrel.  Thanks to the fantastic Isler Custom Gun works carbon fiber handguard, combined with the weight savings provided by the In Lead We Trust barrel, my SIG MPX Carbine weighs a scant six pounds as compared to the seven pound weight of my SIG MPX PCC.  Folks, a 7lb. rifle is impressively light.  But SIX pounds? I’ve never handled such a lightweight rifle.

I took both of the rifles out to my local range to do some testing.

I ran approximately 500 rounds through my MPX Carbine – about 300 rounds of 124gr. Blazer Brass, and 200 rounds of Federal Syntech 150gr.  Not being a reloader, I practice with Blazer, and shoot Syntech (which Federal developed specifically for the practical shooting sports) in competition.  There were no failures with either ammunition.  The really interesting part of the test session came when I did side by side comparisons with the ILWT barrel equipped MPX Carbine, and the SIG MPX PCC.  I did a series of four-shot drills from 10 yds./30 ft. – shoot two on the left target, reload, and shoot two on the right target.  What I was primarily interested in comparing was 1)was there a difference in muzzle movement?  2)Was there a difference in shot placement/grouping?  3)Was there a difference in the handling characteristics?

I first tried the 124gr. Blazer Brass.  I felt this was an important test as many shooters (particularly newer shooters) both practice and compete with relatively inexpensive factory loads.  Both rifles shot very controllably at match speeds with the Blazer Brass, but the MPX PCC shot noticeably flatter with less perceived muzzle rise than the MPX Carbine with the ILWT barrel.  I attribute this to the compensator muzzle device on the MPX PCC – I did not have a muzzle device attached to the ILWT barrel.  Despite this fact, I found that the shots fired from the ILWT MPX Carbine consistently had smaller groups.  Here are a couple of photos from my targets (click to enlarge if needed):

MPX PCC:

ILWT MPX Carbine:

I shot several evolutions of this drill, and while there were slight variations, the above photos well represents the trends I consistently saw.  With the MPX PCC , the shot placements were not as well grouped and tended the favor the lower right-hand corner.  There are some mitigating factors outside of the barrel which may account for some of these results.  Different triggers were used in the two rifles – a Hyperfire Competition Trigger in the ILWT MPX Carbine as compared with the stock Timney in the MPX PCC.  It’s difficult to say for certain how much impact on the results (if any) the different triggers would account for.  But I can I can say that while the results were counter-intuitive to what I was seeing in terms of muzzle movement, the results were consistent.

I also tested both rifles using the Federal Syntech ammo.  The Syntech has a much lower power factor than the Blazer Brass – probably not enough to drive the comp on the MPX PCC.  As such, the observed muzzle movement during multiple shot strings was much less pronounced between the two rifles.  Both shot similarly flat using Syntech.  Regardless, I observed the better shot placement and tighter groups under multiple, rapid shot strings with the ILWT MPX Carbine.  Again, the MPX PCC tended to drive the shots lower on the target.  Here are two more target photos – this time doing 10 shot bursts (on the beep fire 10 shots as quickly as possible, starting with the stock on belt):

MPX PCC:

ILWT MPX Carbine:


Again, these results were very consistent under multiple strings of fire.

Of course, observed muzzle movement and group trends aren’t the entire story.  Most practical shooting sports involving a PCC require speed.  The data was quite consistent in this regard as well – I shot significantly faster with the ILWT barrel equipped MPX Carbine.  Note the times on the timer shown in the 1st two photos above.  I consistently shot .25 to .5 of a second faster with the ILWT MPX Carbine.  That may not sounds like a lot, but multiply that over six stages of a local match, or 10-12 stages of a Level II or III match.  The time difference is significant – matches are often won by less than one second.  Not to mention that the much the reduced weight of the ILWT MPX Carbine just feels so much lighter and easy to maneuver.  Once again, there are other factors at play – the ILWT MPX Carbine was equipped with the Isler carbon fiber handguard for example.  It would be interesting to see if there was a comp I could place on the ILWT barrel to test, but based on what I am seeing, you absolutely do NOT have to have a comp with the ILWT barrel.

The SIG MPX PCC is a fine choice for the entry-level competitor looking for the best out-of-the-box MPX to use in local competition.  But for the more seasoned competitor, who is looking for next level performance, I strongly recommend an In Lead We Trust MPX barrel.  Lighter, faster, and completely reliable.