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Accuracy Loss After Change from HS Stock to Metal Chassis -- Help Needed

It's not a chassis- which is a solid, machined chunk of aluminum. It's a stock with an aluminum bedding block...

Certainly not impressed with the machining of the block, if the ridges are intentional beats me why...looks like it was gnawed out by a beaver.

Wanna have some educational fun? Lay down some contact blueing on that block and press your receiver onto it.

I'll bet you've got less than 25% contact.
 
I've been following along and wanted to suggest some prussian blue and test fitment.

IF IT WERE MINE. I'd skim bed the whole thing, as well as the contact points on that bottom metal where it meets the aluminum block
 
6MMsteve said:
when I first used a chassis and bipod I shot all over the place but the same action barrel with a stock shot well, it just took some time to get use to not shooting on a fixed rest, a little more time and better trigger pull with good bag in rear and back to shooting just as good actually shot a .108 with a bipod
Click to expand...
Everything was shot off from a bag no bipod was ever used
 
tobnpr said:
It's not a chassis- which is a solid, machined chunk of aluminum. It's a stock with an aluminum bedding block...

Certainly not impressed with the machining of the block, if the ridges are intentional beats me why...looks like it was gnawed out by a beaver.

Wanna have some educational fun? Lay down some contact blueing on that block and press your receiver onto it.

I'll bet you've got less than 25% contact.
Click to expand...
This is what I’m going to do I just have to find some contact blueing
 
A few people have mentioned it but along with bluing to check contact surfaces this is another check you can do. Pretty much play with action bolts and have a think about what's happening. You'll work it out.


 
bulldog284 said:
This stock doesn’t have a vblock,the clearance around the Barrel is a lot,the bolts are not bottoming out in the front or back. As you can see there is a recess in the aluminum block on the underside so the bottom metal witch has pillers molded in the bottom metal can fit very nicely and the bolts heads are in direct contact with the aluminum making good contact.
i measured to make sure the recoil lug is not bottoming out on the bottom of the chassie there is .020 clearance But is in contact with chassie on the backside of the recoil lug.
The bolt handle is not in contact with anything.
action was torqued at 65 inch pounds.
I shot groups with a Nightforce nx8 and tract scope no difference.

thank you for all the input
Click to expand...
In the third photo it looks like the action screw is contacting the inside of the rear pillar. I had a new rifle build that had the same thing going on, shot very inconsistent. Took it apart and found the above, opened up the hole to clearance it and problem solved.
 
Definitely looks like rear action screw is making contact with the pillar but maybe just the pic?
I had a bedding block stock making contact with the rear action screw and it wrecked accuracy until the pillar was relieved. Skim bedding the block helped also since it wasn’t a v block.

I would bed the bottom metal to the chassis and skim bed the action to the chassis, the finish on the block looks pretty rough.

One of my actions shoots better in my Matrix chassis without bedding than it does in the laminated, bedded stock it was originally in. No change in load. It also fits me much better than the laminated stock and I prefer the vertical grip. Vudoo I had, hammered in the Matrix also. Friend has a MDT ACC and accuracy is a wash between it and his bedding block, laminated stock, same load.
 
bulldog284 said:
This stock doesn’t have a vblock,the clearance around the Barrel is a lot,the bolts are not bottoming out in the front or back. As you can see there is a recess in the aluminum block on the underside so the bottom metal witch has pillers molded in the bottom metal can fit very nicely and the bolts heads are in direct contact with the aluminum making good contact.
i measured to make sure the recoil lug is not bottoming out on the bottom of the chassie there is .020 clearance But is in contact with chassie on the backside of the recoil lug.
The bolt handle is not in contact with anything.
action was torqued at 65 inch pounds.
I shot groups with a Nightforce nx8 and tract scope no difference.

thank you for all the input
Click to expand...
Check clearance between bolts and the holes looks like impression of screw threads in rear bolt hole
 
DaWhit said:
Definitely looks like rear action screw is making contact with the pillar but maybe just the pic?
I had a bedding block stock making contact with the rear action screw and it wrecked accuracy until the pillar was relieved. Skim bedding the block helped also since it wasn’t a v block.

I would bed the bottom metal to the chassis and skim bed the action to the chassis, the finish on the block looks pretty rough.

One of my actions shoots better in my Matrix chassis without bedding than it does in the laminated, bedded stock it was originally in. No change in load. It also fits me much better than the laminated stock and I prefer the vertical grip. Vudoo I had, hammered in the Matrix also. Friend has a MDT ACC and accuracy is a wash between it and his bedding block, laminated stock, same load.
Click to expand...
The alum block is not smooth smooth there is a feel to it but very uniform in a patter, the bolts are not bottoming out and from what I can see they don’t touch I took some measurements here they are
stock holes .280
bottom metal .262
action bolt diameter .248
im ordering some Prussia blue and I’m going to do some more test when they come in,

thanks for the feedback
 

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bulldog284 said:
The alum block is not smooth smooth there is a feel to it but very uniform in a patter, the bolts are not bottoming out and from what I can see they don’t touch I took some measurements here they are
stock holes .280
bottom metal .262
action bolt diameter .248
im ordering some Prussia blue and I’m going to do some more test when they come in,

thanks for the feedback
Click to expand...
I would love to know the machining process used to produce that...no idea how that "chatter"-like pattern resulted, looks like a gazillion passes with a tiny end mill. Perhaps one of the CNC mill guys here can enlighten me.

I don't see any way a perfect radius to mirror the receiver contour could be machined absent a specific form cutter- which obviously wasn't used here.
 
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tobnpr said:
I would love to know the machining process used to produce that...no idea how that "chatter"-like pattern resulted, looks like a gazillion passes with a tiny end mill. Perhaps one of the CNC mill guys here can enlighten me.

I don't see any way a perfect radius to mirror the receiver contour could be machined absent a specific form cutter- which obviously wasn't used here.
Click to expand...
It almost looks like they made the finish ruff so the bedding would have something to adhere to. LOL
 
tobnpr said:
I would love to know the machining process used to produce that...no idea how that "chatter"-like pattern resulted, looks like a gazillion passes with a tiny end mill. Perhaps one of the CNC mill guys here can enlighten me.

I don't see any way a perfect radius to mirror the receiver contour could be machined absent a specific form cutter- which obviously wasn't used here.
Click to expand...
This type of machining is only done on this chassie the others are normal
 
LVLAaron said:
Why is this threaded?

View attachment 1619756
Click to expand...

I'm hoping...
It wasn't threaded from the factory.
Both of the soft aluminum pillars have been "threaded" by the steel action screws because of the misalignment.

Clearly an issue. The receiver could be "floating" because the screws are threaded into the pillars.

Definitely need to make that go away- you need to create clearance in the pillars when you bed it so the screws don't contact the pillars.
 
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