Does stock torsional stiffness matter?

[ToddM]

So I was curious on people's thoughts about stock torsional stiffness and accuracy/repeatability?

For example, say you have your rifle on a bipod, and you exert a lateral or rotational force against the stock (say pushing against the cheek piece) if the forearm/stock deflects is that bad, or does it even matter? Seems like it might be a bigger issue (if it's even an issue) on a bipod than bags, as the rifle is allowed to twist on a bag that probably minimizes the torsion force but a locked down bipod isn't going to allow the mount point to move, so the stock twists.

One thing I've noticed is many stocks/chassis are pretty stiff vertically when you try and press the forearm to the barrel, which is the common test everyone seems to try, but some will twist quite easily, especially in stocks that do not have a full aluminum spine and just use a bedding block etc. I noticed this recently when I was setting up a new MDT Field Stock. It's quite stiff vertically when you try and compress it toward the barrel, but put it in a bipod and put just a couple pounds of pressure to either side of the cheek rest and was shocked how much twist there was. Obviously it's an extreme budget priced option, sacrifices have to be made at the price point, and it does not have a full aluminum spine. So for giggles I put a few other stocks/chassis I had into a bipod and the variation was pretty huge. Not surprising the higher price/weight/mass was usually more resistant to this force, but not always. I'd imagine a lot of factory plastic stocks would do horribly in this test as well.

AI AT: not surprisingly rock solid
TRG: again the only movement I could feel/see was bipod "slop"
CZ 457 bedded in a factory varmint precision chassis: I was surprised how much twist this one had, but it's also not very stiff vertically
10/22 in a bravo: I'd say middle of the pack
r700 in MDT field stock: by far the most flex, not even close
r700 bedded in HSS precision stock: pretty stiff, almost no movement
Sako s20: pretty solid middle of the pack.

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For my use, the low price of the MDT Field stock was not the main motivating factor, I wanted something under 4lbs, that had a "skin" not bare metal, was setup for detachable mags, had a vertical grip, and was not super bulky, but the amount of flex in the forearm seems concerning.

 

[Emerson0311]

Sideways pressure will push you off target when recoil occurs. Also, considering what the Field Stock costs, your concerns are the same as whining about how flat tires aren’t hard enough to break rocks.

 

[ToddM]

I don't know that I fully agree with that, the HS precision/Bravo/Oryx stock really isn't priced any/much higher than the MDT Field stock or other similar options like the Magpul hunter etc., but they are massively stiffer. So if the stiffness matters.......I'd say that's a valid buying/decision point. Now the Bravo/Oryx for example is a bit more expensive, but the HS Precision was cheaper, it doesn't have all the bells/whistles but if torsional stiffness results in better accuracy/repeatability, some might favor having a stiffer stock with less bells and whistles over a flexy stock with them at similar price points.

 

[oldrifleman]

Yeah it matters how the stock moves. If I load the stock and then it moves then it sucks. If the movement is predictable and measured and does not involve barrel contact or bedding shift, all is good.

 

[Emerson0311]

I don't know that I fully agree with that, the HS precision/Bravo/Oryx stock really isn't priced any/much higher than the MDT Field stock or other similar options like the Magpul hunter etc., but they are massively stiffer. So if the stiffness matters.......I'd say that's a valid buying/decision point. Now the Bravo/Oryx for example is a bit more expensive, but the HS Precision was cheaper, it doesn't have all the bells/whistles but if torsional stiffness results in better accuracy/repeatability, some might favor having a stiffer stock with less bells and whistles over a flexy stock with them at similar price points.

If the features are not what a guy is looking for, there is usually a factory model with a reasonable stock, rather than buying a replacement. I reiterate that sideways pressure is not sound for good shooting. If loading a bipod a bit, or a bag, bends the stock into the barrel, that is a problem. I will run an mloc ARCA on the bottom of mine, so it will be a bit stiffer, and maybe a little weight for balance. At this price point, it will never compare to a rock solid full featured chassis of any type. An adjustable cheek rest and vertical palm positioning finish out my requirements. As for too slippery, non-skid tape will probably go on the grip. I’m comparing it to a ACC Premier, ACC Elite, and Oryx on my other rifles. Taking my wife out for a basic dinner is well over $100. The field stock is one step above a pure impulse purchase. Spend double and there are a lot more options.