Aluminum Chassis and Temp Changes

Discussion in 'Equipment Discussions' started by Left Hand Dave, Aug 31, 2018.

  1. Left Hand Dave

    Left Hand Dave Well-Known Member

    Jan 10, 2016
    I have an XLR chassis that I am thinking of using on my 7-300Win Mag. Those of you that use aluminum chassis do you see POI shifts with temp changes? Seems that when the aluminum contracts and expands with temp changes it woul affect POI and maybe group size. I am looking st a temp swing from 70 degrees to 20 degrees from load work and sight in to hunting.

  2. ShtrRdy

    ShtrRdy Well-Known Member

    Jan 14, 2012
    I'm not a materials or mechanical engineer but I was looking at the thermal expansion coefficients for aluminum and steel. Aluminum has about twice the expansion than steel. But the numbers are small. Like a 10 millionths of an inch per degree per inch of material for steel. A Rem 700 action has a diameter of about 1.35". For a 50 degree span of temperature the diameter would increase by about 0.0006". ( if I did the math right).

    I have two legacy AICS and I haven't noticed a change in impact over a 70 degree span.
  3. Greyfox

    Greyfox Well-Known Member

    Jan 21, 2008
    I haven’t seen any effects from temperatures with either my MPA or MDT chassis. I suspect that this would have shown up long ago with the bedding chassis’ used in many of the synthetic stocks like the HS Precision.
  4. troupe

    troupe Well-Known Member

    Feb 13, 2012
    I have used chassis over the years, from -12 to upper 90's and never noticed any changes
  5. shaughn

    shaughn Well-Known Member

    Oct 30, 2014
    I have an MDT HS3 using a Stevens 200 action with a 26 inch heavy Varmint profile SS in 300 Win Mag and it has been shot from 102 F in the shade to as low as -40 F and if there is any change due to temperature it is so minimal as to probably need very precise testing equipment to find it.