Balancing MPA Matrix rig w/ 18-20" barrel?

[pronelife]

use case: NRL22 (50-100yds)

scenario: with 26" barrel rifle balanced at front of mag well (pre-barricade stop). Gray Ops barricade stop made rig butt heavy; added competition side rails and 4 x Gray Ops XL steel weights to regain balance. would like to try 18-20" barrel but concerned with balance, welcome input/advice from folks running similar barrels.

build: RimX / MPA Matrix / Competition Side Rails ( 1.1 lbs) / 4 X Gray Ops XL side rail weights (2.8lbs / Gray Ops barricade stop / 26" ACE barrel ACE contour (1.250 -> 1.10 @ muzzle)) / NF ATACR 7x35

UPDATE: chassis is Matrix, not Pro. with added Comp Side Rails it has same/similar features as Pro without adjustable bag rider.

 

[Rob01]

Edited as I missed the side rail addition so much be an original Matrix. You can add internal weights. Also you can lighten the rear by taking out the screw and wheel and make it something like the new Matrix Pro II lightweight set up. Pic below. Some of the collars below. Can do that with the cheek and buttstock.

Cheek Riser Locator Collars - MasterPiece Arms, Inc.

Attach these shaft collar to your guide rods on any MPA Chassis cheek riser assy to provide a quick, easy and consistent method of relocating your cheek riser to your predetermined position. These work with chassis with and without a thumb wheel system. For those with a thumb wheel design...

masterpiecearms.com

 

[rimfired]

I ran a factory B14r steel in MPA ESR for a while with full internal weight kit and grayops XL steel weights and was still slightly butt heavy.

 

[TubbyT223]

18-20 in a regular mpa is going to be like fighting a bear. You’re not gonna win. 22-24 1.20 is the min. 22 is with a tuner. I have literally spend $1000 trying to make it work with Tikkas, CZ and I have a rimx now. DST makes some weights that might help and work but you’re going to have to hit. Both ends. Buy the light buttstock kit and then add about 3-4 pounds.

 

[4O6shootist]

Is it the first gen matrix or the pro or newer? The first gen were heavy as F in the rear. I was running a 26" hvy varm, fat bastard, all the weights possible up front and a ckyepod to get the balance where I wanted it. Think I shot 2 matches and sold it. The pro and newer are lighter in the ass.

 

[TubbyT223]

Is it the first gen matrix or the pro or newer? The first gen were heavy as F in the rear. I was running a 26" hvy varm, fat bastard, all the weights possible up front and a ckyepod to get the balance where I wanted it. Think I shot 2 matches and sold it. The pro and newer are lighter in the ass.

Concur. If it has the aluminum bag rider, that is almost a pound. I switched to the pro 2 comp and I only had to add 8 oz with a 22” 1.20 and cortina tuner.

 

[rimfired]

I'm now running a Vanquish and a 24" 1.18 straight taper and balances great with no internal or external weights (or the weight of a bipod)

 

[Rob01]

Is it the first gen matrix or the pro or newer? The first gen were heavy as F in the rear. I was running a 26" hvy varm, fat bastard, all the weights possible up front and a ckyepod to get the balance where I wanted it. Think I shot 2 matches and sold it. The pro and newer are lighter in the ass.

I asked the same thing then edited when I reread his post and he said he put the side rails which aren’t needed on the pro or pro II so has to be the original matrix.

 

[Fig]

You are not the first person to have trouble balancing the Gen I and ending up with a rifle that is too heavy for comfort. Putting weight on the very end of the barrel will let you use the least weight.

The best solution I've seen is to put the rifle on an edge at your balance point, take off the thread protector, and then add weights (big catfishing weights work well) on a string till it balances. Add that up/weigh that, and then find a tuner or a compensator that weighs the same. There are a ton of different weights from the bench rest people (such as https://www.killoughshootingsports.com/benchrest-c12/benchrest-tuners-c30). If it's really bad and you can't find one heavy enough, you may have to cut a length of a larger, shot out barrel and thread it to fit. If you don't have one that has let go someone will probably give you one + shipping, because they're tomato stakes.

I've seen quite a few guys who have done this with a shot out barrel, and I'm not convinced that they often don't increase the precision just like a tuner anyway. YMMV.

 

[Lightning8]

I had an original MPA Matrix and I never could get it to balance for rimfire with a RimX and a 20+ inch straight.

I picked up a certificate for a XLR Envy Pro - I use that with my RimX and 20+ (22?) inch barrel. It is just lighter in the butt.

 

[LuvDog]

I never tried with my matrix, but I had a Vudoo with 20" MTU in a BA Comp.

I had to run all the internal weights and external brass weights to even get close to balancing. It still didn't move the balance point as far forward as I wanted.

I think in an ESR, you might be able to do it. I ended up just switching to an MDT ACC Elite and even then it's still about an inch further back than I'd like.

You only other option would be something like the DST DaShaft.

Overall, I just don't think it's worth it. The total package became too heavy to move around easily.

 

[pronelife]

updated original post to reflect chassis is original Matrix, not Pro.

Much thanks for everyone's input, it confirms my suspicions. I knew it was a$$ heavy before I started but I focused on solving problems and forgot about the bigger picture. Beginning to think Jack Daniels as a study buddy may not have optimized this equation. I'll give @Rob01s suggestions a try and think about what my next build should look like.