Salient Arms International MK25 Tier 1 Prototype

The Salient Arms International (SAI) MK25 Tier 1 Prototype was the most enjoyable gun I’ve ever owned. I’m not saying it was perfect, but I can say unreservedly that it made it much easier for me to shoot faster and more accurately than I ever had in the past. Interestingly enough when I first received the firearm back from SAI I thought that perhaps some of the modifications were unnecessary. Let me go on record saying I was completely wrong, I apologize, and there wasn’t a thing done to this gun that didn’t serve a purpose one way or another.

When SAI and myself first discussed collaborating on a SIG project, we had a couple of goals in mind. While I had been a fan of the SIG platform since switching to appendix inside-the-waistband carry, there were several things about the platform that were bothersome. There were also some things that I was perfectly happy with, or that I thought were non-issues, which SAI assured me could be improved on. I’ll try anything once.

Modifications to the SIG MK25


  • The frame was heavily modified to facilitate a higher grip on the gun, including reshaping the beavertail area, undercutting the frame at the base of the trigger guard as well as the trigger guard itself.
  • A texture was added to the front strap, underside of the trigger guard, and front of the trigger guard.
  • A set of SIG Tac Ops grips were shortened and reshaped to create a useable mag-well for concealed carry purposes.
  • The fire control group was modified for decreased reset and smoother take up.
  • The trigger was reshaped and lightened.
  • The hammer was lightened.


  • The slide was lightened and re-profiled and forward serrations were added.
  • A reduced power Wolff recoil spring added.
  • The barrel was replaced with a custom Bar-Sto match fit barrel.



When I first received the gun back from SAI I was incredibly impressed with how much higher a grip I was able to get. While I’ll agree that bore axis is often times over stated in terms of aiding or hindering recoil management, it certainly doesn’t hurt to be able to get a higher grip on the gun.

SAI actually removed enough material from the frame at the base of the trigger guard that when I first released pictures of the modifications several very knowledgeable people were worried that the frame would crack if placed under a heavy firing schedule. 25,000-plus rounds later I’m happy to say those fears were unfounded, but at the beginning of the test it was certainly of concern to me.

SAI did a wonderful job of reshaping the beavertail portion of the frame as well, although there was one sharp corner that they missed. It ended up breaking open a callous on the web of my shooting hand around the 17,000-round mark. In all fairness, I don’t think it’s something that would ever be an issue for the average shooter. Also, SAI plans to address the problem on the production version.

The texture added to the front strap, underside of the trigger guard, and the grips was very aggressive. Several people commented that it was going to tear my hand up in short order. It actually felt perfect to me, seeing as I prefer for the gun to move as little as possible when I am shooting. That’s not to say that eventually I didn’t bleed, but that was more of a function of the firing schedule than the texture itself. I actually made it through almost 10,000 rounds before my hands started to show any signs of wear at all.

Oddly enough the texture they added to frame held up worse than my hands did, eventually completely flaking off the underside of the trigger guard, and partially flaking off of the front strap. In talking with SAI as the test progressed they have diagnosed why that issue occurred and have devised a way to fix it on future guns, although I doubt there are many people who would shoot theirs enough, under the conditions I was shooting in, to see the issue in the first place.

The grips themselves were shaped perfectly and made reloads a little more consistent for me at speed. Unfortunately at some point during the test, either through the firing schedule, or more likely due to me over-torqueing a screw, one of the grip screw bushings became completely stripped. I threw a set of the excellent VCD Grips stippled E2 single piece grips on the gun and drove on. Note to self: “as tight as I can possibly get it” is not a correct torque setting for a grip screw. Whoops.

Trigger and Internals

By manipulating the internals of the gun and lightening the hammer SAI was able to significantly improve the trigger feel over the stock pistol. The double action pull was incredibly smooth, with a single action reset that was even shorter than the SRT trigger I had been shooting. When I finished the test and picked up my stock SIG to re-familiarize myself before I started carrying it again, I found myself short-stroking the single action trigger pull of the SRT trigger for the first few hundred rounds. If you had asked me before the test if it’d be possible to short-stroke an SRT trigger I would have told you that you were crazy, and I’d have been wrong.

One of the more subtle things SAI did was reshape the trigger; lightening it by boring holes into its face. This was another area that garnered attention when I first released photos of the gun. For me the increase in tactile awareness that the lightening holes imparted had a direct connection to improved trigger control. I found myself much less likely to throw a shot either in dry fire or live fire because of the constant feedback I was getting from the face of the trigger. I think SAI may have inadvertently discovered something cool with this mod, I know I’d like to shoot another pistol with a similar trigger face to see if it is an actual benefit or just my imagination.


The most clearly visible modification to the MK 25 was the work done to the slide. In addition to completely changing the profile of the slide itself, SAI added lightening cuts to reduce slide weight, and forward serrations to aid in overall manipulations of the pistol.

The idea behind the slide lightening is that by decreasing the mass that is reciprocating back and forth on top of the frame of the gun, you also decrease the felt recoil and muzzle flip to the shooter. An additional benefit is that you see an increase in slide velocity, which theoretically puts your sights back on target faster while possibly increasing reliability, assuming the slide isn’t cycling faster than the springs in the magazine can keep up with.

It was no surprise to me that the most clearly visible change to the gun was also the change that garnered the most criticism from the internet. The most common concern that people seemed to have was that by cutting holes in the slide you were likely to introduce debris that would somehow effect reliability. I did not find this to be the case, and my experience with both Glock G34s and Beretta M9s supports the idea that openings in the slides will not affect reliability.

As for the added serrations at the front of the gun, while I did find them to aid in weapons manipulations, especially one handed malfunction drills, I wouldn’t be distraught if they were not present on the production gun. I would prefer having them on the gun over not, this was probably the modification that I was the least excited about from a performance standpoint. From a visual standpoint, I thought that they improved the overall look of the gun, but as always, beauty is in the eye of the beholder.

One Malfunction

The pistol experienced exactly one failure over the course of 25,104 rounds, and it was directly linked to one change the SAI made to the gun. When changing the weight of the slide, SAI tried to tune the recoil characteristics even further by putting a Wolff reduced power recoil spring into the gun. This caused a problem that took 3,124 rounds to develop, but when it occurred it completely locked the gun up. It took two experienced shooters with a rubber mallet and a punch to clear the malfunction.

The SIG factory spring is a multi-strand affair that is supposed to increase overall service life. This is what the pistol and its guide rod are designed for, and what the gun is most happy with. The Wolff spring, on the other hand, is a single-strand design. With the single-strand design, the end of the spring itself can become trapped between the dust cover and the guide rod, locking the gun up completely.

I actually feel bad about this problem because it’s a known issue with a work around already in place, but I had no clue it existed until it happened to me. One of the reasons SAI had me on board for the project in the first place was my familiarity with SIGs. When they were building the gun they discussed my thoughts on using a reduced power Wolff spring and I informed them that I didn’t think it would cause any issues. Shows what I know. The production version of the gun will have this issue addressed.

The interesting part is that this happened after 3,123 previous rounds had gone down range without a hitch. Let me put that into perspective: I will usually shoot around 1,500 rounds before I declare a gun reliable enough for me to feel comfortable carrying it. It was an interesting feeling when I considered the ramifications of a similar malfunction, however unlikely, occurring in a defensive situation. Carrying a second gun is never a bad idea. For what it’s worth, this was the only malfunction the gun had, and afterwards it went on to fire 21,980 consecutive rounds, with very little to no cleaning, without further issue.


The Bar-Sto match fit barrel that SAI fitted into the gun was simply incredible. While I had originally intended to ransom rest the gun at the start of the test, conflicting schedules with the owner of the ransom rest prevented me from doing so. That, coupled with an incredibly short shooting schedule, meant that I did not get a chance to test the gun for accuracy until after 25,000 rounds had been fired. The results were simply incredible.

From 25 yards I fired three five-shot groups supported from sandbags using Asym Precision 115-grain action match ammo. The smallest group measured just a shade over one inch while the widest group was right around the 2.25-inch mark. Did I mention this was after 25,000 rounds had been fired? I really regret not getting the chance to shoot it for groups earlier in the test; I suspect it may have performed even better when fresh.

The Verdict 

The million-dollar question is whether or not it will be worth the money to have similar work done to your gun when SAI releases the commercial package? The answer depends on who you are and what you like. Official pricing hasn’t been released yet, but from looking at their other product offerings I can take a wild guess and say it won’t be cheap.

For me, the improvements to the platform are substantial enough that I haven’t enjoyed shooting my other SIG nearly as much since giving up the Salient. As always your mileage may vary, but I’ve already sent another SIG to them to be upgraded and, unlike the prototype, I will be paying for the work that’s done to this one. Spending my money on something is about the highest personal endorsement I know how to give, and in my limited experience SAI makes quality stuff that works and works well.

So what happened to the pistol you might ask? I decided at the end of the test that, instead of letting it gather dust in my safe, it would be better to try and do some good with it. With the help of Crye Precision and Salient Arms International we were able to raise over 6,300 dollars for military charities, including The Unit Scholarship Fund, at Crye Precision’s SHOT Show silent auction. While I deeply miss the test gun, I am very glad that we were able to help some folks out with it once everything was said and done.

By John Johnston. Originally published in the April 2014 issue of GunUp the Magazine.

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