MPA Matrix / Curtis Vector build


Nov 20, 2019
MPA Matrix / Curtis Vector​

I set out to purchase a “Buy Once Cry Once” PRS style rifle. I have built rifles in the past and I have always ended up spending 50% more changing everything that I compromised on with the original build or buy. This time I was going to do it right.

After a great deal of research and talking to people that owned multiple brands I settled on all of the components below.

Area 419 Sidwinder break

Triggertech Diamond straight shoe trigger

Zero Compromise ZC527 MPCT2

MDT 1.125 0 MOA Mount

Below are the Items that were in question.

Curtis Vector Vs. Defiance Deviant

MPA Matrix Vs. MDT ACC

What I ended up with is below.

MPA Matrix

Curtis Vector

Area 419 Sidewinder

Triggertech Diamond straight (and then curved)

MPA Mount

Nightforce 7-35 in MOA

The Optic

I have used a great deal of Nightforce product, and it has all been wonderful. Some of it has broken out of warrantee and they have still warranted the product. Everything mechanical breaks even things that are known to be built for rough duty. A small issue with this scope came up during use. Every once in a while, the illumination would come on after recoil. Nightforce repaired the problem quickly without any question at all.

The second issue I would like to address is MOA. I have seen people argue about MOA vs MIL for hours. I personally believe that MIL is a better option for a multitude of reasons, but MOA does have one redeeming quality. People with too much money and not enough sense purchase MOA scopes then realize they should have purchased the same scope in MIL. They then sell the MOA scope to me at a greatly reduced cost. And that is how I ended up not purchasing a ZC527.

The Chassis

I have not used a MDT or MPA chassis so I based my decision completely on reviews and marketing information. I also considered Foundation and Manners stock but I decided on a chassis.

I am coming from shooting AR platform rifles. One, (of many), headaches of using an AR is the grip. Often times the limiting factor of how low, or the amount of angle you can achieve is limited by the pistol grip. This and, the fact that you could change out the grips on the Matrix made the decision for me. On paper they all looked very similar.

Running the MTU contour 26” barrel and one weight near the mag well of the fore end the gun weighs 20 pounds. That is also with an Atlas bipod.

The adjustable mag catch works great. I do not know why more manufactures do not offer this as I found it extremely useful and easy to set up.

Before I continue down this road let me say that I have shot three matches with this setup and have had zero issues. The MPA product is well made and is as advertised. I am going to focus on the things that I had to do to make this chassis work for me so this will look like a negative review of the product. That being said I have since seen many of these chassis set up in stock trim and their users are better shooters than I am. The action fit well in the chassis and never came loose. The arca rail was easy to use and did not slip at all even with thumb screw clamps. The bridge cleared the MTU barrel with no issues. And before I made the changes below it worked well.

That being said, I am 5’ 9” or 5’ 10” and 205 pounds. I have the cheek bones of a 12 year old girl apparently as I have yet to meet a man that can see through my scopes. I also have hands on the small side of average. So please take into account the fact that I am not an average shaped person in the respect of build.

However, that is one of the main reasons that I chose the Matrix as it is supposed to be fully adjustable and have multiple grips that can be changed out to suit different sized hands. They also pride themselves on the grip that they produce for the Competition chassis which indicated to me that they would probably be ahead of the game in this area.

I ended up using the vertical 2 grip. I chose this option because it placed my hand closer to the trigger than the rest, and I do prefer the vertical to the swept. To be honest I thought for sure that I would like the swept but it placed my hand farther to the rear and that was really the main factor for not liking it as well.

I shot the rifle for a few weeks and I could never really get a good feel on hand placement. I then used some foam and started to build up and area between the trigger guard and the grip to stop my hand from riding up the grip towards the action. This was much better. I emailed MPA and expressed my concern with the fit and had no response. I then built up the area with an epoxy putty and ground it down until it had a good fit for the straight shoe trigger that I was running. I coated the putty with JB weld so it would handle the weather and abuse.

I ran this for a while, and it was much better but I barely had room for my remaining three fingers below the buildup. Even though I had no problem maneuvering the rifle I feared there could be a safety concern at some point. I then reduced that area about so my middle finger fit slightly behind the trigger guard. I realized that now my finger is engaging the flat shoe in the middle and not towards the bottom and it did not feel the same each time. So I purchased another Triggertech Diamond with a curved shoe. I do prefer the straight triggers but, in this chassis, the curved is a better option in my case.

Cheek Riser

Originally setting up the stock I found that I could not adjust the cheek riser high enough. The retention bars were to high for the set screws to engage with. I ended up building up a cheek riser with craft store foam to get the correct height, and then I wrapped it in hockey tape. This also allowed me to thin it out and shift the top of the riser to the right side, so I did not have to cant my head to get on the scope. Prior to doing this I was going to purchase an accessory from MPA that would have allowed me to slide the cheek riser to the right. I do appreciate that they offer this accessory but do think they should include it with a chassis named the Matrix.

To be clear the reason I built up the riser as opposed to purchasing the accessory was because the riser would not go high enough and still lock down with the set screws.



I shot the rifle like this in all of the matches that I attended and it worked very well. I have done this to other stocks but I had hoped that I would not have to do so this time.

A problem was notice when I went to move the riser. I loosened the set screws and I could not adjust the riser. I was able to move it enough at the range to get the height I needed after I cut the “hillbilly riser” off at the range. When I returned home I tore into the problem.

When I added the “hillbilly” I locked the riser down in a low position so I could get more of a taper to the thin top. When I did this the set screws engaged the lock down shafts above the standard flats that are provided. I did not know this at the time, but found out that the set screws cratered out the shaft. When I went to raise the cheek riser, I had to tap it up with a soft dead blow while rotating the adjustment screw. I then filed down the blemish and had to polish the shafts up to get them to go back into the stock. The original finish looks to be a Parkerize treatment. I think Parkerizing is great but in this dry non lubricated duty I think it was a bad choice. A polished stainless shaft would be much better suited.

It was then that I noticed the flat on the shafts and how short they were. They were also not 90 degrees from the set screw engagement. I squared up the flats so the next time I locked it down the set screws would engage the flats properly.

The original engagement is about 3/8” of travel. That is ridiculous to think anyone from a 5’ slim person to a 6’ 10” heavy built person would only need 3/8” of difference.

The picture above shows the original lock down after I cleaned it up and polished it. The flat shows the original finish.

I used a Dremel and added length to the engagement area. I then lowered the riser completely and engaged the set screws. The picture below shows the engagement point.


The picture above shows the flats with the bottom of the riser sitting on the top of the chassis. This is not its lowest position that is shown two pictures up. I would consider this to be a normal area for the riser for most people

I would recommend replacing the set screws with brass or polymer non marring tips as well.

The But Pad

If you look at the above pictures you will notice that the but pad is rotated 180 degrees. The pictures of the cheek riser with the foam and hockey tape show the but pad in the highest position available. Rotating the pad will give you the most height that you can get out of it.


The but pad is not as comfortable when it is rotated but I like to have the top of the pad approximately the same as the top of the barrel. You can see that there is adjustment if you would like to offset the but pad left or right.

Also be aware that if you move the but pad at all from its centered position the pad becomes more exposed to damage as it is not protected by the mounting hardware as well.

I would recommend replacing the set screws with brass or polymer non marring tips as well.

Compared to most high-end chassis this is not acceptable. I have used J Allen, KRG, and MDT. All of those products have much more adjustment in both the riser and the but pad.

Lesson I learned is try it before you buy it if you can. In the end I do like the way the Matrix fits me but only after I had to modify it heavily. And for a chassis that is supposed to be fully adjustable and customizable I think they really missed the boat with a product that could have been a straight up winner takes all, and still could be if they improve on what they have.

Curtis Vector

If I had played it safe, I would have went with the defiance. I know many people that use this action and they have Zero dissatisfied customers that I know of. I am sure there are people out there but again I have heard nothing but good things. I have used them as well but to now serious extent and I have never owned one.

I have always loved the feel of a Weatherby action. The first time I ever worked a bolt on a Weatherby I wanted one. Since I do not see anyone running the Weatherby I looked for a short throw action that was popular in the PRS field of use. There are quite a few but the Vector was a stand out. I read some negative reviews but, the problems people were describing looked like they would be easy to overcome such as ACIS magazines. I was right.

Just to be clear on this one I am happy with the Curtis Customs Vector and would recommend them to anyone that is willing to take the time to set it up.

I have talked to many gun smiths and people in the trade and they all agree that there is no action out there that will run in any chassis / stock with any ACIS style magazine. So if you are a person that wants a rifle that will work out of the box buy one from a quality producer or gunsmith that will deliver a finished product.

Now that that has been said, I will get into the AW magazine conversation. Talk to anyone that is in the industry and they will steer you away from AW magazines. I want to run them so I was willing to suffer through the process.

This is my process and I do not recommend that you follow it this is my story alone and it may have negative results for anyone else.

I feel that most problems with magazines is not the magazine but the fit. When I see a rifle have feeding issues while pushed into or onto something I believe the problem to be the fit.

I started by setting the MPA adjustable mag catch as high as I could. The AW magazines have to have pressure to actually snap into place. This keeps the magazine from rocking forward when pushed into something. KRG and J Alen have a few other tricks to keep the magazine from rocking as well but even without their additions seating the magazine high worked.

I then had to file down the top of the AW magazines because the bottom of the bolt lugs, not the bolt, impinged on them. They were basically a knife blade when I was done. I did not modify them in any other way. Prior to this I destroyed an AW magazine trying to modify the lips but then realized the true issue.

I then inserted an ACIS magazine. I then removed at least an 1/8” from the lips and had to reshape them because the bolt would impinge on it when it was pressed into or onto anything. The magazine runs great never had a problem.

As a side note another Vector owner was having problems with his magazines and was talking to people that were insisting that he shave down his mag catch to lower his magazine. I loaned him my ACIS and he ran it for the remainder of the match with no issues.

So it is my belief that you should set the magazine as high in the action as possible and modify your $70 to $90 magazines to fit. Again that is my belief and I am not a gunsmith, or an engineer. I am a guy with a Dremel and a hammer.


Now comes the hard part.

I am running 6.5 Creedmoor. Using an AW magazine there is a sharp point that will catch the shoulder from time to time and dent the case. I rounded it off and problem solved. Now every so often the round will kick to the opposite side of the chamber and hit the back of the barrel instead of entering the chamber.

I ended up removing a portion of the feed ramps all the way into the end of the action. I did this incrementally and only removed what was needed while still leaving the raceway intact.


This solved the problem with Creedmoor. I do not recommend that anyone does this and if they do they should have it done by a gunsmith. I also would not advise this on any other ammo. I believe that this allows the bullet to enter the chamber before the feed ramps force the round toward the center while still retained in the magazine. I do not know if this will work on any other round.

Now that that has been said I LOVE the Curtis Vector action. I could have set this up for an ACIS but did not. This action is smooth as silk on satin and has given me zero problems.

I do not consider what I have done to the feed ramps to be a problem. I did this so I could run AW magazines 100% of the time with pressure from any and all directions and IT DOES.

Also I torque my barrels on at 100 foot pound as per my gunsmith. I have no experience, comment, or opinion on the set screw style installation. If my gunsmith said that he would recommend the quick change option that is what I would have done.

Again listen to a qualified gunsmith not me.


Aug 4, 2020
Thanks for the review, was going back and fourth between the matrix and the competition chassis, for my build.