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

[Carl S]

A full and stress free bedding job,eliminates another variable that can cause accuracy issues.

 

[bulldog284]

The barrel is not touching anywhere lots of clearance
im wondering if different torque settings would help? It’s just that it’s such an accuracy change I have seen it that bad before, I would have thought it would at least stay around 3/4. Moa. How much of a load change do you think it needs?
Im thinking of bedding the recoil lug and skin coating the aluminum bedding block area with JB weld?

 

[BuffaloBill]

I take it the before and after is with the same scope? A couple years ago I was chasing an accuracy problem that turned out to be my scope.

 

[DaveTooley]

I have learned to move the contact point on the front tube towards the rear. YMMV

 

[swd]

Check for anything touching that shouldn't. Front action bolt touching the bolt lug, trigger touching the stock, bolt handle contacting anything other than action body. Recoil lug bottoming in the lug recess etc...

 

[Infrequent Shooter]

Hope you get it back to shooting good.

 

[DirtySteve]

Try doing this....

You are being redirected...

 

[Rick300]

I find that a chassis just doesn't shoot the same as a conventional stock. It takes some getting used to. While I have a couple of chassis rifles that shoot small, I doubt I will do another one, conventional stocks, for me, are much easier.

 

[T Kop]

I’d start low and go up in torque settings, it’s easy and have nothing to lose.

 

[ShtrRdy]

If the OP could do a powder charge test by exploring incremental powder charge weights on either side of what worked in the past, ..... that would be interesting.

 

[jelenko]

If the OP could do a powder charge test by exploring incremental powder charge weights on either side of what worked in the past, ..... that would be interesting.

I was thinking the same - like two steps up and two steps down in .3gr steps from the current charge.

 

[nwmnbowhunter]

You might learn you can’t get used to a chassis. I tried and tried. Wasn’t for me

It took me over a hundred shots to get the groups to come down. I had to be very technically sound or else I'd pull shots.

I moved on as well.

 

[DLT]

It took me over a hundred shots to get the groups to come down. I had to be very technically sound or else I'd pull shots.

I moved on as well.

I know my biggest problem was the flat bottom stock. I didn’t want to spend the time, money to correct it.

 

[Fuj]

The chassis stock in question is a molded in v-block. It has it's own
can of worms over a full one piece aluminum chassis. Biggest problem
with the cast chassis over a mono block, is temperature......I do not bed
my chassis but do rub fit them in tight. I also do not bed my lug. Trick
on my end is to place a piece of .004" mylar tape on the lug face after
checking the lug face cut is true to the V-block. I use 3 screw actions and
tighten them to stock specs. period......Best I can tell the OP to do is to bed
that particular stock, check channel clearance, and do your normal load
work for what you have......Note.....Are the action screws compressing
composite plastic material as it snugs down the action, 0r is there a direct
metal contact at the bottom of the block ??

 

[bulldog284]

The chassis stock in question is a molded in v-block. It has it's own
can of worms over a full one piece aluminum chassis. Biggest problem
with the cast chassis over a mono block, is temperature......I do not bed
my chassis but do rub fit them in tight. I also do not bed my lug. Trick
on my end is to place a piece of .004" mylar tape on the lug face after
checking the lug face cut is true to the V-block. I use 3 screw actions and
tighten them to stock specs. period......Best I can tell the OP to do is to bed
that particular stock, check channel clearance, and do your normal load
work for what you have......Note.....Are the action screws compressing
composite plastic material as it snugs down the action, 0r is there a direct
metal contact at the bottom of the block ??

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

 

[Fuj]

Does'nt look like a V-block for sure, but it's still molded in......

 

[6MMsteve]

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

 

[X Count]

Bed it. Easiest way to get full stress free contact between the action and stock. Allows you to be confident you can diss an re assemble without loosing your zero or accuracy.

 

[Mike Casselton]

I had a CZ 527 one time that shot very well. Took it apart and cleaned it. When I went out to check the zero, the groups were horrible.

Took me forever to figure out the problem, but while reassembling, I didn't get the magazine box placed correctly into the action and it was binding against the stock and not allowing the action to sit fully against the stock.

Everything was tight, but just not seated correctly. Once I figured it out and got the magazine box back in correctly, the gun shot like it used to.

The secret to the 527 is to have the empty magazine inserted into the bottom metal before putting it together.
With the mag in place, the bottom metal can't go in crooked.

It took me a few tries to learn that trick.

 

[STS]

im wondering if different torque settings would help?

In my experience, changing group size with different torque settings, is the gold standard indicator that the rifle is in need of quality bedding work. I'd be willing to bet that if your rifle responds to different torque settings, it will demonstrate action stress with a dial indicator.