Aluminum chassis, thermal variations and POI shift.

[Bushwalker]

Hi everyone!
I´m new in this forum and I´m from Europe.
I´d like to ask you about your experiences with full aluminum chassis, it´s thermal variations, and POI shift. I am divided between a laminated wood stock with aluminum pillars and bedded, and a aluminum chassis for my Bergara B14 Sporter Varmint in .308. Does the aluminum chassis have some expansion or contraction due air temperatures like in hot summer days or in winter extreme cold days? If yes, can that thermal variations cause POI shif and affect the rifle accuracy? I´m from a place where the lowest winter temperatures are about 23ºF and in the summer can reach about 111ºF. I would like to know what are your opinions about this item. Thanks.

 

[Vodoun daVinci]

I'm a whore for aluminum chassis. No Idea about POI changes in heat but it gets plenty hot here in the Summer and I have never encountered this phenomenon. Mirage causing shift? All the time. Barrel mirage is really annoying and can affect what one is seeing.

VooDoo

 

[Newbie2020]

I’m no metallurgist or engineer but @voodoo is right. The effect of 40 or 50 degrees F on expansion of the aluminum bedding block would be infinitesimally small and likely purely hypothetical. But the mirage coming off a hot barrel can cause huge effects in the scope.

Hopefully a smart person can chime in here.

 

[Newbie2020]

@Voodoun daVinci

 

[THEIS]

Hi,

IMO you would have to be able to read the wind at the exact bullet flight path down to a half mph difference before I would worry about the alloy of chassis and the alloy of the receiver expanding/contracting at different rates/temperatures enough to affect the accuracy you can hold.

Can such thermo-expansion variances be shown in a lab experiment? Yes
Can you outshoot those variances? Highly unlikely.

Sincerely,
Theis

 

[orkan]

Given the action is torqued to the chassis to the proper spec, historically this is not something that has surfaced as a problem during real world shooting. POI can wander as things heat up, but the most common culprit of this is the barrel itself, rather than the stock/chassis.

 

[XTCBoltAction]

I know that the Eliseo all aluminum chassis is used a lot in long range competition from temps in the 40's to 90's [degree F] by some top flight shooters. I've never seen any discussions on the effect of temperature on accuracy in the various forums dedicated to competition/accurate rifles. I'm pretty sure if there were any issue at all, it would be discussed.

 

[orkan]

I know that the Eliseo all aluminum chassis is used a lot in long range competition from temps in the 40's to 90's [degree F] by some top flight shooters. I've never seen any discussions on the effect of temperature on accuracy in the various forums dedicated to competition/accurate rifles. I'm pretty sure if there were any issue at all, it would be discussed.

It's been discussed heavily among benchrest groups... though not because of the thermal expansion, but the harmonic issues. It's thought by many that wood or composite dampens harmonics better and makes rifles easier to tune.

 

[XTCBoltAction]

Very interesting.
Benchrest is a whole 'nuther world!
Aren't matches determined by hundredth or thousandths of an inch in group?

 

[Bushwalker]

Hi,

IMO you would have to be able to read the wind at the exact bullet flight path down to a half mph difference before I would worry about the alloy of chassis and the alloy of the receiver expanding/contracting at different rates/temperatures enough to affect the accuracy you can hold.

Can such thermo-expansion variances be shown in a lab experiment? Yes
Can you outshoot those variances? Highly unlikely.

Sincerely,
Theis

Yes, if there were any issues about the accuracy with the chassis due temperatures, the military didn´t adopted their ultimate sniper rifles made of aluminum alloys, eg. US Army and USMC. I guess the tests and trials for these rifles are very rigorous and set on different environements with extreme hot and cold.

 

[Bushwalker]

Hi,
Thank you for your opinions about this item.
BTW, somebody here in this forum have experience or have already heard about the SAG (Sureshot Armament Group) chassis for the Remy 700? Here it goes a picture...