MDT ACC Elite

#151
Baron23 said:
@GBMaryland

Please address @MDT_OFFICIAL (Anthony’s) question about “the rifle is shooting”.

Also, when I’m over your place today, if you want to make a vid of this, I’m willing to help.

Cheers
Click to expand...
yes, I took a Rifle out, attempted to shoot groups and found that I was having a pretty difficult time. I had assumed that I was just having an off day… but it would be a really off day for me… then I started taking a little bit of a closer look at things.

Honestly, I was just really confused.

I ordered the control bridges in order to help deal with mirage in front of the scope… and I ordered the NV bridge because I wanted to use a pic rail elite iron bipod.

I then noticed that the flex in the whole chassis assembly basically went away. I.e. If I pushed on the barrel with my finger, and only my finger, it effective we didn’t move anymore.

Conversely, with the control bridges and night vision bridge off, the forearm effectively warps, side to side, when any movement is put on the action through the barrel or by twisting butt stock.

I’ve seen this with other chassis, just substantially less, and they also tighten up when they are equivalent of a controlled bridge is installed.
 
#152
GBMaryland said:
I don’t have to muscle it… All I have to do is take my index finger and slightly push on the end of the barrel, and the whole rear of the gun will move a quarter of an inch from side to side. It can also be done if I grab the end of the butt stock and twist it slightly. (the lack of significant force required to do this cannot be overstated.)
Click to expand...

Where are you specifically seeing this movement? Can you clarify using specific points on the chassis?

-Anthony
 
#153
MDT_OFFICIAL said:
Where are you specifically seeing this movement? Can you clarify using specific points on the chassis?

-Anthony
Click to expand...
We specifically see it flex with the whole forearm twisting side to side.

What you see is that the rear end of the stock will cant left to right in a twisting motion.

…and we went back and we checked the ACC Premier, and you are completely correct: It’s a lot worse.

we took a bunch of videos will try to post them.
 
#155
GBMaryland said:
We specifically see it flex with the whole forearm twisting side to side.

What you see is that the rear end of the stock will cant left to right in a twisting motion.

…and we went back and we checked the ACC Premier, and you are completely correct: It’s a lot worse.

we took a bunch of videos will try to post them.
Click to expand...


Yes, please do it sounds like you are shifting the whole rifle around, which will occur as it's bolted into the chassis. And with it shooting, I assume, well, this sounds like a non-issue at all. But yes, you can move things around if you push on them; the ACC series was intended with the free recoil principle in mind.

-Anthony
 
#156
GBMaryland said:
yes, I took a Rifle out, attempted to shoot groups and found that I was having a pretty difficult time. I had assumed that I was just having an off day… but it would be a really off day for me… then I started taking a little bit of a closer look at things.

Honestly, I was just really confused.

I ordered the control bridges in order to help deal with mirage in front of the scope… and I ordered the NV bridge because I wanted to use a pic rail elite iron bipod.

I then noticed that the flex in the whole chassis assembly basically went away. I.e. If I pushed on the barrel with my finger, and only my finger, it effective we didn’t move anymore.

Conversely, with the control bridges and night vision bridge off, the forearm effectively warps, side to side, when any movement is put on the action through the barrel or by twisting butt stock.

I’ve seen this with other chassis, just substantially less, and they also tighten up when they are equivalent of a controlled bridge is installed.
Click to expand...

Saw the posts in the other thread, and read the inference that the chassis and it's forend stiffness (or lack thereof), was causing POI issues. Which I didn't understand. The posts in this thread paint a bit of a clearer picture.

I wonder if you two are loading into the rifle way too much. I could see how that could induce some torque into the system, especially with the bipod all the way out at the end.

I bet different (better) technique and perhaps even moving the bipod a bit closer to the shooter (having bipods way out is known to have an adverse effect on precision/POI in a lot of cases) would solve your issue.

IMO I think this is a shooter issue, not a chassis' issue. Is anyone else having this issue?
 
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#158
Whelp that blue one isn’t blue any more.

IMG_0996.jpeg

733984EF-EDF0-4F5A-864C-B51993B97A7C.jpeg
 
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#160
kthomas said:
Saw the posts in the other thread, and read the inference that the chassis and it's forend stiffness (or lack thereof), was causing POI issues. Which I didn't understand. The posts in this thread paint a bit of a clearer picture.

I wonder if you two are loading into the rifle way too much. I could see how that could induce some torque into the system, especially with the bipod all the way out at the end.

I bet different (better) technique and perhaps even moving the bipod a bit closer to the shooter (having bipods way out is known to have an adverse effect on precision/POI in a lot of cases) would solve your issue.

IMO I think this is a shooter issue, not a chassis' issue. Is anyone else having this issue?
Click to expand...
I am not seeing any flex in either of my ACC Elites, with or without the control arms installed, unless I hulk grip the barrel and press on the outside of the chassis with the palm of my hand with substantial force. Basically having to pull the barrel towards the wall of the chassis.

I did have a small issue with stock assembly wobbling, however the screw had backed out a couple of turns. I tightened it up after a few dabs of blue loctite and haven't had any issues since.
 
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#161
I have no issues hitting targets at a 1000 yards and more with the rifle’s I own.

Yes, there are times when my day is not as good as other days because I’m not taking my time and doing things by the numbers.

However, compared to my TRGs, the foundation centurion, and the vision chassis…. There is a crazy amount of flex in the ACC elite.

wHow much of that translates to an accuracy issue or not is hard to say. In a static test it is very clear that the forearm torques in a rotational manner and the butt stock moves nearly quarter inch side to side without man handling things.

I’m sure people would like to pretend that doesn’t matter, but it’s highly unlikely that it doesn’t matter.

In so far as the comment that I might be loading the bipod too much… Well that’s just ridiculous. Of course you’re gonna load the bipod When your firing from the prone position, and then you’re going to practice your fundamentals. How much do flex is actually seen in real life conditions is another story… but we all know it doesn’t take more than 1/10 of a mil for significant differences at distance.

That’s the point that I am making.
 
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#162
GBMaryland said:
I have no issues hitting targets at a 1000 yards and more with the rifle’s I own.

Yes, there are times when my day is not as good as other days because I’m not taking my time and doing things by the numbers.

However, compared to my TRGs, the foundation centurion, and the vision chassis…. There is a crazy amount of flex in the ACC elite.

wHow much of that translates to an accuracy issue or not is hard to say. In a static test it is very clear that the forearm torques in a rotational manner and the butt stock moves nearly quarter inch side to side without man handling things.

I’m sure people would like to pretend that doesn’t matter, but it’s highly unlikely that it doesn’t matter.

In so far as the comment that I might be loading the bipod too much… Well that’s just ridiculous. Of course you’re gonna load the bipod When your firing from the prone position, and then you’re going to practice your fundamentals. How much do flexion is Ashley seen in real life conditions is another story… but we all know it doesn’t take more than 1/10 of a mil for significant differences at distance.

That’s the point that I am making.
Click to expand...

1.) If I’ve read your previous posts correctly, you are clamping the far end of the 18 inch forend into a vise, and then pushing on the muzzle of the barreled action. How long is your barrel? 26 inches? 30?

If so you’ve set things up to have the highest possible amount of leverage on the front action screw & recoil lug. I would say you’re definitely “manhandling” the chassis, you’ve just found a way to use leverage instead of brute force.

2.) Exactly zero of the really proficient shooters I’ve spent time with load their bipod these days. Because it’s both unnecessary for good recoil control and it can be difficult to load consistently in every situation for every shot.
 
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#163
Your point with lever as well taken.

In this case, 24 inches.

Though, I did end up putting a 28 1/2 inch barrel in the sucker. 🥴

As I said, with the control bridge is installed all of that flex, for the most part, goes away.
 
#164
@GBMaryland have you tested your barreled action in anyone else’s ACC elite? This sounds like you may have a one-off issue. If you don’t have another available to test, I would contact MDT customer service and send it back to get fixed. Also, can you post a video so we can visually see what’s going on in case others are having this issue?
 
#166
GBMaryland said:
Your point with lever as well taken.

In this case, 24 inches.

Though, I did end up putting a 28 1/2 inch barrel in the sucker. 🥴

As I said, with the control bridge is installed all of that flex, for the most part, goes away.
Click to expand...
Yes, leverage is the big factor here, and you will notice as well as you move your hand up the barrel this effect is minimized, in really interesting how quickly it goes away the more you reduce IE sliding the bipod or changing where you press on the barrel.

How many hoods did you put on the chassis?

-Anthony
 
#167
MDT_OFFICIAL said:
Yes, leverage is the big factor here, and you will notice as well as you move your hand up the barrel this effect is minimized, in really interesting how quickly it goes away the more you reduce IE sliding the bipod or changing where you press on the barrel.

How many hoods did you put on the chassis?

-Anthony
Click to expand...
One NV bridge and two smooth ones because that’s just about how many you need to get nearly full coverage. Could get away with two with a longer sunshade.

I personally was running two per chassis and changed it to three on my main girl because the Theta ARD is short.
Chesapeake said:
@GBMaryland have you tested your barreled action in anyone else’s ACC elite? This sounds like you may have a one-off issue. If you don’t have another available to test, I would contact MDT customer service and send it back to get fixed. Also, can you post a video so we can visually see what’s going on in case others are having this issue?
Click to expand...
He can borrow one of mine anytime, but he’s gonna have to bring his own rear end for that stupid LOP. 😂
 
#168
Seems a number of us have been shorted washers/action mounting bolts for the ACC Elite; I found this info on their website, so thought I would share...and recommend checking your boxes, if you have the chassis on ice waiting to build.

You may or may not need the washers, but doubt your action manufacturer sent a 2.5" bolt, so a much-needed part. :)


ACC Elite
Remington 700 SA & Clones
Rear - 1/4"-28 X 2-1/2" SHCS (103762)
Front - 1/4"-28 X 5/8" SHCS (103274)
Washer - 1/4" MIL-SPEC WASHER, 0.270" ID, 0.460" OD, 0.032" THICK (106824)
 
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#169
MDT_OFFICIAL said:
Yes, leverage is the big factor here, and you will notice as well as you move your hand up the barrel this effect is minimized, in really interesting how quickly it goes away the more you reduce IE sliding the bipod or changing where you press on the barrel.

How many hoods did you put on the chassis?

-Anthony
Click to expand...
All of that is fine and we’ll but doesn’t explain the dramatic difference in group size that @GBMaryland experienced without top stuff installed (and hence visible flex…yes, manipulating the end of the barrel) and with the top stuff (and hence no…or extremely little flex). And I know that he can shoot and do it consistently.

The idea of swapping into @TheOE800 chassis (with and without too stuff) is a good one. Issue will travel with the BA or it won’t. Good fault isolation approach.

Cheers
 
#170
Baron23 said:
All of that is fine and we’ll but doesn’t explain the dramatic difference in group size that @GBMaryland experienced without top stuff installed (and hence visible flex…yes, manipulating the end of the barrel) and with the top stuff (and hence no…or extremely little flex). And I know that he can shoot and do it consistently.

The idea of swapping into @TheOE800 chassis (with and without too stuff) is a good one. Issue will travel with the BA or it won’t. Good fault isolation approach.

Cheers
Click to expand...
And we know my chassis with three bridges is sub-MOA at distance.
 
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#171
TheOE800 said:
And we know my chassis with three bridges is sub-MOA at distance.
Click to expand...
Yes we do. And you shot it great last week.

But swapping GB’s BA into your chassis and shooting with and without top stuff would tell us if there is something unique to his.

Or, you could shoot groups with/w-o top stuff and see if it reproduces his experience.

All - I do want to be clear, I love MDT, have a number of their excellent products, and they are a very helpful and appreciated presence on the Hide, IMO.

We are not bashing them but rather just trying to ferret out why the performance seen by my good friend @GBMaryland was so different with/w-o top forearm pieces.

Cheers.
 
#172
Keep in mind, when properly loading a bipod, unless there is just a ridiculous amount of flex in a chassis....you shouldn't have any flexing of the barrel and such away from the chassis.

However, you can absolutely load a bipod enough to see flex in almost any chassis.

Not saying anyone is loading bipods wrong.....just pointing out that proper loading of a bipod is far, far less aggressive than many do in practice.
 
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#178
kthomas said:
Is anyone else having this issue with the ACC?

There's lots out there. If this is truly an issue with the chassis, I feel like we would be hearing similar reports from other people. Anyone?
Click to expand...
No.

I just designed a chassis weight that encompasses the barrel with a 1mm radial clearance, which is about double the flex I can get out of it.

IMG_3525.jpeg
 
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#183
Terp said:
Seems a number of us have been shorted washers/action mounting bolts for the ACC Elite; I found this info on their website, so thought I would share...and recommend checking your boxes, if you have the chassis on ice waiting to build.

You may or may not need the washers, but doubt your action manufacturer sent a 2.5" bolt, so a much-needed part. :)


ACC Elite
Remington 700 SA & Clones
Rear - 1/4"-28 X 2-1/2" SHCS (103762)
Front - 1/4"-28 X 5/8" SHCS (103274)
Washer - 1/4" MIL-SPEC WASHER, 0.270" ID, 0.460" OD, 0.032" THICK (106824)
Click to expand...
Mine came without the action screws washer :confused:. Can't easily find them either.
 
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#187
eprom said:
Hopefully, I think I don't need them for my Zermatt origin action. At least, I don't see an issue yet; I made only one trip to the range with it. I should email them btw.
Click to expand...
We would be happy to get a new set sent out to you. Please email us directly at [email protected].
 
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#191
GBMaryland said:
Yeah, @TheOE800 is correct with that. The current bag rider goes down at an angle.

The issue with the cheek riser is that you need an ungodly amount of torque on the thumb screw to mostly-eliminate what seems to be 1cm in total travel from left to right.

It's not very useful having to torque the thumb screw down so much that the cheek riser is no longer field serviceable.

It's a great chasis... but, that's the eyeball business end of the rifle and keeping your cheek centered in the optic is hugely important.

I have video of the issue... just need to figure out how to post it.
Click to expand...
With my chassis all you need is to snug the thumb screws up to eliminate any play.
 
#192
VH96 said:
With my chassis all you need is to snug the thumb screws up to eliminate any play.
Click to expand...
So we discovered that what the problem was is that there wasn’t enough height adjustment for the cheek riser…

Basically, if you had a scope that required you to use 1.5 inch height rings, there is a lip on the bottom of the threaded posts that gets stuck inside the thumbscrew clamp/post/screw assembly. That means you have to torque the hell out of it to keep it from moving because you’ve run out of threaded metal post.

The way you solve this you order the butt stock posts/pins which are much longer. Then install those in the place of the ones for the cheek riser/comb and end up with significantly more adjustment.

What was really strange is that when you do all of that the cheek riser will still lower enough that is at the starting point with the shorter threaded pins.

You add to that the fact that you have to have control bridges or NV bridges installed to prevent flex while loading a bipod, and I just didn’t like it compared to other stock options.

(I’ve actually seen a lot of people selling these chassis after playing with them for a brief time.)

In contrast, I went out and picked up a vision chassis, all the adjustment that I needed right out of the box and I didn’t have to buy anything else.

MDT makes a very nice product, but it does not fit everybody straight out of the box. Whereas some of their competitors stuff does… don’t get me wrong. I freaking love my Centurion, but I had a similar situation where I had to get taller posts, and I had to add a significant length of pull.
 
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#193
GBMaryland said:
So we discovered that what the problem was is that there wasn’t enough height adjustment for the cheek riser…

Basically, if you had a scope that required you to use 1.5 inch height rings, there is a lip on the bottom of the threaded posts that gets stuck inside the walking clamp/screw assembly. That means you have to torque the hell out of it to keep it from moving because you’ve run out of threaded metal post.

The way you solve this you order the butt stock posts/pins which are much longer. Then install those in the place of the ones for the cheek, riser and end up with significantly more adjustment.

What was really strange is that when you do all of that the cheek riser will still lower enough that is at the starting point with the shorter threaded pins.

You add to that the fact that you have to have control bridges or NV bridges installed to prevent flex while loading a bipod, and I just didn’t like it compared to other stock options.

(I’ve actually seen a lot of people selling these chassis after playing with them for a brief time.)

In contrast, I went out and picked up a vision chassis, all the adjustment that I needed right out of the box and I didn’t have to buy anything else.

MDT makes a very nice product, but it does not fit everybody straight out of the box. Whereas some of their competitors stuff does… don’t get me wrong. I freaking love my Centurion, but I had a similar situation where I had to get taller posts, and I had to add a significant length of pull.
Click to expand...
Gotcha.

Did you get the original vision chassis or the pro? I had the original with the comp fore-end for my trg 22 but got rid of it in like 2 weeks. I couldnt get over how needlessly far forward the barricade stop was, made balancing the rifle a pain. Got the elite like a month ago for my first proper prs build. Still waiting on the barreled action from the smith, but Ive had my friends 223 tikka action in it and shot it and it really is a gamechanger for me (so far) versus my old setup (trg22 with vision handguard). Really eager to get the action in so I can start doing proper load development and training. Being from Finland tikka is pretty much a nobrainer, and too bad the centurion or the matrix pro isnt offered in that inlet. Heard rumors that the vision pro should be getting a tikka inlet soon, that would have been my second choice versus the elite.
 
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#194
And pricing is always different, but I got the elite for pretty much the same amount of money with addons (2 control bridges, 1 piece internal weight, dampners) as the original vision chassis with comp fore end and folder. And the elite pretty much balances like that perfectly.

With the vision I would have had to get the internal weights and exterior wieghts for balance and the top cover for significantly more on an already expensive rifle.

Pretty much my only complaint about the elite so far is that irs 6061 and not 7075. Ive already gotten slight marks on the inside of the front action screw hole by the screw threads hitting it while changing barreled actions in the chassis. Not that it matters regarding use but is kinda a bummer
 
#196
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#198
I notice pretty significant zero shifts when installing my CDG Barreled action into my acc elite chassis. I have a black one that shift my zero high by about 3/4", and a FDE one rhah move it the same amount up, and about a 1/2" left, the rifles precision seems to degrade a bit as well at distance, groups have more vertical. I can use the same zero in my atx and xlr envy pro chassis, it doesn't move swapping between them. I wonder if the contour of the CDG action is causing this. I know I can put my archimedes in all of my xlr, atx, and acc chassis and the zero holds pretty dang true. Anyone else experience this when moving a zerod rifle from one chassis to another? Even my fuzion has had minimal to no shift between a foundation, xlr, atx and the elite. It seems isolated to the CDG.
 
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#200
4O6shootist said:
I notice pretty significant zero shifts when installing my CDG Barreled action into my acc elite chassis. I have a black one that shift my zero high by about 3/4", and a FDE one rhah move it the same amount up, and about a 1/2" left, the rifles precision seems to degrade a bit as well at distance, groups have more vertical. I can use the same zero in my atx and xlr envy pro chassis, it doesn't move swapping between them. I wonder if the contour of the CDG action is causing this. I know I can put my archimedes in all of my xlr, atx, and acc chassis and the zero holds pretty dang true. Anyone else experience this when moving a zerod rifle from one chassis to another? Even my fuzion has had minimal to no shift between a foundation, xlr, atx and the elite. It seems isolated to the CDG.
Click to expand...

I can't say I have a lot of experience with the CDG, but I would actually guess that the diameter of the action is a *little* on the small side. We have found that some aftermarket actions fit a little "deeper" into our inletting and can cause some fairly strange issues. For the most part, all R700 clones are fairly consistent, but there are some outliers and it is hard to account for all of their nuances without sacrificing performance.
 
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