MDT LSS-XL chassis flex

[Matman2010]

I built a Howa 1500 LA 300 Win mag and put it into a LSS-XL Gen 2 chassis. The chassis seems to have a lot of flex between the mag well and forend. Anyone have any ideas on how to fix the flex? I was shooting at 700 yards yesterday and just noticed that with little movement I could make the cross hairs go way off target from the chassis flexing. Maybe my best bet would be to switch to a different stock?

 

[Northernjets]

I'd honestly be more inclined to suspect the bipod than the chassis. I'd be impressed if you could drive a Harris hard enough to flex a solid chunk of aluminum without the feet rotating on you first. The interface between the bipod and the chassis also has a foam pad inbetween, which I can probably safely guess would be more of a flex point than anything else. I've never liked the sling stud attachment mechanism for the Harris.

 

[broke_again]

Those chassis do have flex to them. The best way we found to take some out was to bolt up an Arca rail to the forearm.

 

[DownhillFromHere]

Consider the attachment of the bipod - a single sling swivel stud. Then consider the very narrow flat portion of the LSS-XL chassis to which the Harris tightening mechanism pulls the bipod. See how far out the "wings" of the bipod extend from the chassis? The result is that a relatively small leverage in going to result in crosshair movement - the bipod flexes, not the chassis, unless you're using a pair of channel locks to torque the bipod's tightening screw.

I know. I have the same stock and and bipod. When the bipod is mounted on a chassis or stock as wide as the Harris "foot," it's much more stable.

Solution is, as posted earlier, an M-lok ARCA rail to provide a much stiffer foundation on which to mount the Harris or other bipod. Or another stock with an ARCA rail or wider "base" against which a Harris bipod can seat.

 

[Shadow knows]

I have a SA with an atlas and have not notice any movement. Is this a LA issue(?) in conjunction with harris ?

 

[Matman2010]

Consider the attachment of the bipod - a single sling swivel stud. Then consider the very narrow flat portion of the LSS-XL chassis to which the Harris tightening mechanism pulls the bipod. See how far out the "wings" of the bipod extend from the chassis? The result is that a relatively small leverage in going to result in crosshair movement - the bipod flexes, not the chassis, unless you're using a pair of channel locks to torque the bipod's tightening screw.

I know. I have the same stock and and bipod. When the bipod is mounted on a chassis or stock as wide as the Harris "foot," it's much more stable.

Solution is, as posted earlier, an M-lok ARCA rail to provide a much stiffer foundation on which to mount the Harris or other bipod. Or another stock with an ARCA rail or wider "base" against which a Harris bipod can seat.

Ive torqued the bipod down, Yes it has some flex if you drive it, but I dont drive my bipods. I have it sitting next to me right now. If I take one finger and push on the scope the chassis flexes( yes that is some leverage on it, but you can also push on the bolt and the chassis flexes as well), bipod does not flex or move at all. Ill look into ARCA rails, but for the price of them and the fact that my bipod is not moving Ill probably try to figure something else out. Thanks!

 

[DownhillFromHere]

Ive torqued the bipod down, Yes it has some flex if you drive it, but I dont drive my bipods. I have it sitting next to me right now. If I take one finger and push on the scope the chassis flexes( yes that is some leverage on it, but you can also push on the bolt and the chassis flexes as well), bipod does not flex or move at all. Ill look into ARCA rails, but for the price of them and the fact that my bipod is not moving Ill probably try to figure something else out. Thanks!

My point is the single-point attachment (sling stud) coupled with the narrow bearing surface on which the bipod seats contribute to the movement. It is what is is. If you clamp that stud tight in a heavy bench vise, the scope reticle is still going to move with minimal finger pressure. If you clamp the chassis fore-end itself in the vise, you're going to need a lot more pressure to move the reticle.

 

[Matman2010]

My point is the single-point attachment (sling stud) coupled with the narrow bearing surface on which the bipod seats contribute to the movement. It is what is is. If you clamp that stud tight in a heavy bench vise, the scope reticle is still going to move with minimal finger pressure. If you clamp the chassis fore-end itself in the vise, you're going to need a lot more pressure to move the reticle.

Went out to the shop and fired up my plasma table and made a little test bracket.

Did a little bending

and fit this onto the forened

Bolts are just temperary till I get the correct ones to make it look clean. Im going to try this bracket out, may end up making it fit the whole forend and go under the bipod on the next one. This fixed 90% of the flex, now the bipod is moving like you said. So I may make this longer to try to give the bipod more of a bite.

 

[DownhillFromHere]

Went out to the shop and fired up my plasma table and made a little test bracket.

View attachment 7107100

Did a little bending
View attachment 7107101

and fit this onto the forened
View attachment 7107103

Bolts are just temperary till I get the correct ones to make it look clean. Im going to try this bracket out, may end up making it fit the whole forend and go under the bipod on the next one. This fixed 90% of the flex, now the bipod is moving like you said. So I may make this longer to try to give the bipod more of a bite.

Awesome. Very nice!

 

[FishDr]

Now I want one ! What is the weight of this chassis with your full length mod?

 

[Matman2010]

Now I want one ! What is the weight of this chassis with your full length mod?

I have not done a full length stiffening bracket yet. Planning on taking this one out and seeing how it shoots. This one only adds like 15.5oz (Thats what my cad drawing says)

 

[Wheres-Waldo]

I’ve found the LSS XL flexes like a wet noodle unless you bolt something on the bottom to stiffen it up.

Also, be very careful where you clamp on it (PIG/HOG Saddle) as the action inlet area flexes just as much as the rest of it.