[Solved]Barrel bending technical questions...

    I have determined that I need to permanently  bend a barrel 0.087".Barrels flex and then return to their original position.How far,in terms of percentage  or by factor, do I have to bend it to get it to stay?

    Formulas, and terms relating to modulus of elasticity,yield point,and elastic limit,all relate to PSI forces.I know I can bend the barrel,and I'm not concerned with figuring the required forces.How can I know how much to deflect it?From the clamp point to the point where I would apply the bending force measures  15.5" on a .22 cal. barrel.

    I'd rather avoid the bend it-try it-bend it-try it,overbend it-bend it back foolishness.Besides,that can quickly ruin the seals,and leave me with a pretzel shaped mess.

Pleasse help-EricinMaine-

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I corrected my brothers FWB 124 that slammed shut.  The springer barrels are stiff from my experience, and had to go past pretty far for permanent correction.  Everyone has different techniques.  However I like to clamp the barrel block, one block of wood just off the block, and clamp at the end of the barrel.  Of course this is padded with pine.  I have seen 3/4" deflection and more to get movement.

Some like to bend the barrel in the middle, I set mine up as a cantilever off the breech block so you get a gradual bend.  Recommend going slow and check frequently.

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Jason G

Thank You Jason G,I think your approach is the better way to go.I expect that there is a way to figure how far to deflect the barrel for a desired permanent change.

EricinMaine-

I always go by feel and just watch it. Eyeball it and it will be fine. 

They do it by eye at the factory anyway. And just because you bend it .087" doesn't even mean it will hit to the POI you desire. It's more of a trial and error thing. 

If you want to reduce the "rebound or springiness" while bending, heat it with an oxy/acetylene torch. The spring action is greatly reduced or eliminated then, and if you don't go too hot it won't touch the bluing.

Another thing I've noticed, is the FWB barrels are MUCH stiffer and harder to bend than the Weihrauch barrels. I bent an FWB300S and a FWB124 and had to use the shop press. My Weihrauchs I bend by hand in the big bench vise. 

Thankx to all who replied.I ended up drilling a block to use as a clamp against a plank.Then I cantilevered the barrel over the rounded end of the plank and guessed at how much to bend it.This is presicely the way I didn't want to do it,but it turned out well.I wanted  to do it by measure ,and with control.I hoped to learn how to fix a barrel and know I could get just the results I needed.

EricinMaine