Barrel Bending for HW's

[SpiralGroove]

Hey Guys,
As part of an effort to get all my guns on the same page so to speak, I'm thinking of doing the following:

- Center all my scopes - so there dead center.
- Mount scope on rifle and see how much it shoots low.  I don't know if I've ever had one that shot high .
- Once I determine how low it shoots -> out-of-the-box, go to my padded wood vise and clamp the barrel down in the vise with its stock up.  Then slowly tweak the butt stock forward putting pressure to bend barrel upwards.
Do a little at a time and test the gun every few tweaks to make sure you're not over doing it.

In this way, I can remove most barrel droop without resorting to shimming the scope or making other adjustments to compensate for the fundamental issue - The Gun's barrel is drooping. 

[Roadworthy]

If the barrel is not bent I see the fundamental issue as determining the actual cause of droop.  If the barrel is not bent droop is a symptom of a poor fit somewhere.  On a fixed barrel it may be how it is attached to the barrel block - not much you can do there.  On a break barrel there are causes which are easily remedied.

[SpiralGroove]

If the barrel is not bent I see the fundamental issue as determining the actual cause of droop.  If the barrel is not bent droop is a symptom of a poor fit somewhere.  On a fixed barrel it may be how it is attached to the barrel block - not much you can do there.  On a break barrel there are causes which are easily remedied.

Good points Roadworthy ,
What are some of the false symptoms of barrel droop?
What are their remedies?
Thanks,
Kirk

[Taso1000]

Kirk,

If you need to bend a barrel you can make an easy fixture with some blocks of wood and a large eye bolt or c-clamp to apply controlled pressure. 

I have attached a picture of NCED's fixture for ideas.

Thanks,

Taso

[SpiralGroove]

Thanks Taso ,
Ed's got a "home remedy" for just about everything

[Roadworthy]

Addressing only break barrels, the symptom IS the barrel droop.  Put a straight edge along the barrel to see if it's bent at all.  Sight through it - if bent you'll see it.  See if the bore itself is centered within the barrel.  It's not always.  Put a square on the breech face of the barrel.  Is the face perfectly square with the breech block?  It should be.  If not it can prevent proper closure of the action resulting in the perception of droop.  Does the barrel fully close on the gun or does the breech block appear to be going slightly downhill from the receiver?  This can indicate the stop on the breech block hitting the stop on the receiver before the barrel is fully closed.  If the breech seal is sitting slightly proud it can cause the same effect but it will compress to fit within a short time period.  Look the gun over carefully.  Try to analyze exactly what is happening when you close the action.  An airgun is a pretty simple machine but even simple machines can have simple problems which are not always fully obvious.

[SpiralGroove]

Addressing only break barrels, the symptom IS the barrel droop.  Put a straight edge along the barrel to see if it's bent at all.  Sight through it - if bent you'll see it.  See if the bore itself is centered within the barrel.  It's not always.  Put a square on the breech face of the barrel.  Is the face perfectly square with the breech block?  It should be.  If not it can prevent proper closure of the action resulting in the perception of droop.  Does the barrel fully close on the gun or does the breech block appear to be going slightly downhill from the receiver?  This can indicate the stop on the breech block hitting the stop on the receiver before the barrel is fully closed.  If the breech seal is sitting slightly proud it can cause the same effect but it will compress to fit within a short time period.  Look the gun over carefully.  Try to analyze exactly what is happening when you close the action.  An airgun is a pretty simple machine but even simple machines can have simple problems which are not always fully obvious.

So Takeways:
- Put a straight edge on the barrel to see if its "true".
- Make sure bore is centered
- Make sure breech face is perpendicular to breech block.
- Check breech block, receiver stop mating.
- Check breech seal.

Unfortunately, other than the breech seal, it seems bending the barrel is the best solution to all other problems?
It seems it would take more time and $$ to fix most other issues than simply bending the barrel.
Let me know if this seems wrong?
Kirk

[Roadworthy]

I don't know what flat files go for in Bothell but I have several in my toolbox.  Doing it right takes a little time, figuring out the actual issue and then fixing it.  I have done it.  Droop compensating mounts are an easy fix, sure.  I notice most new Diana rifles come with them in one form or another.  If you plan to get all your rifles precisely the same so you can just move a scope from one to another with no adjustment, I don't  see that happening.  Most droop I've seen has been caused by the barrel stop - the solid metal that sticks out above the spring loaded ball or wedge which holds the barrel closed.  That piece hits a block in the receiver stopping barrel closure at a given point.  If the block is shortened, even a few thousandths, the barrel will close a but further.  Use caution and check frequently.  It's a whole lot harder to put metal back.

[SpiralGroove]

Hey Roadworthy,
Files can be had at the premium price of $5 to $10 at home depot, less at harbor freight .
So yes, if I can determine this mating is the problem, I'll definitely try a little filing first as I have more files than I can count .

So far, I have solved all my barrel droop issues by using pieces of yogurt containers as shims under my scopes.  In addition, occasionally, I need to crank up the scope 10 to 30 clicks to gain my height.  The droop compensating mounts seem like a lot of $$ to solve this problem, but they likely work better than shims.

One things for sure, I haven't really spent a lot of $$ on Scopes or mounts.  I routinely use $80 to $150 scopes and $15 to $20 mounts   So far, Hawke 4x12x40 scopes and $150 12x or 16x Leapers scopes w/glass reticles are my spending limit.  These seem fine for shooting up to 80 yards.

No, I wasn't looking to have employ a interchangeable, scope swapping program with my Springers, just looking to simplify the barrel droop phenomena with my Weihrauch springers.

All good suggestions aside, I'm still trying to hold onto bending the barrels a few thousand of a inch to solve most smaller, barrel droop issues .  Maybe I'm just being Thick Headed about this

[Roadworthy]

If you're seeking a droop compensating mount you can try the RWS Lockdown Mount.  It mounts directly onto the dovetail and can be had in one inch or thirty mm.  Nobody seems to carry them any cheaper than Pyramyd though of course you're free to check around.  I don't know the height on them but I'm pretty sure it's at least medium.  The ZR mounts also have built in droop compensation and are kind of a high mount.  I hear of droop in Crosman and Diana rifles but it seems a well kept secret in Weihrauch - or maybe you're the only Weihrauch owner who suffers from barrel droop.  Harbor Freight files may work okay but I prefer to stick with something a bit better, say Nicholson mill (&#^((&^* file.

[WHITEFANG]

From one that bends take the gun out of the stock. Get the realstionship of the barrel to the scope rail for a start. Fixed barrels have droop. I said this many times, you can pull a barrel and re barrel the gun and still have droop. Fixed or brake barrel. And yes it's the block drilling. JMO 💀

[SpiralGroove]

From one that bends take the gun out of the stock. Get the realstionship of the barrel to the scope rail for a start. Fixed barrels have droop. I said this many times, you can pull a barrel and re barrel the gun and still have droop. Fixed or brake barrel. And yes it's the block drilling. JMO 💀

So Fang, you're saying both fixed barrel (under-levers) and break barrels can have barrel droop.  The droop you're speaking of comes from barrel block drilling, completed incorrectly.  If yes, check to see if the scope rail is parallel to the bore.  Also, you often do barrel bending for the above problem. -> Right?

Question:
Do you recommend barrel bending to solve barrel block, mating issues with the receiver stop as discussed above too?  Or do you file the block to make necessary changes? or recommend a droop compensating scope mount?

I know you have likely done a ton of this work, so interested to know how you solve this common problem .
Thanks .... Kirk


   

[WHITEFANG]

I've probably done all the above. On angle breech blocks I have filed some material away. Esp if the breech area showed it was contacting the tube above the TP.
I have and still used the dropper mounts.
 Brake barrels droop for the most is not there or noticed with sighted guns. That's why I say check the rail vs the barrel relationship.

And yes lever guns can have droop. The only thing I can say is the lever guns have rear sights farther down the action.  Now when you scope any gun we are going off the rail. The rail possible is not running with the barrel. But I have pulled lever gun barrels and machined blanks only to find if the gun had droop before the removal it had it with the new barrel.

I'd like to throw in that if the bore is not straight with the OD, which many are not depending on which direction the bore is skewed will result in the scope and barrel not been in line.

I do not mind bending a barrel to fix the problem. 9n some barrels I have found when squaring off the side of the block for left and right relationship that the barrel has shown to be straight off the right side and off some on the left?  I go off the right side and go from there.
But you can go off the top of the block and the barrel with 2 squares and see the droop and that's not going off the scope rail.
If there is droop measuring of the block to barrel I make that square and then check measurements off the rail top and scope rail to the barrel.

It got to help the scope for having enough to adj. Mechanical center is what you really would like to have.

I'vee got a PB weaver 1 peice mount that has front adj built into the mount. This is a camputer HiLux and has the abilities to adj the rear up and down on the scope and used no shims. Instructions tell you to mechanical center the scope. Make all the adj with the mount before adj of the scope. This by far works very good but expensive.
I really do not like shimming scopes.
ED has worked many barrels his way and has had great luck. His bending is different than mine. All I can say is we both bend and like our results. Both methods work. Ed does the mechanical centering of scopes and then tweaks his barrel to the scope. So this tells me it all works if you want to go through the time. Plus adj to close to the end of the scopes limits is one reason for eating scopes.

[fwbsport]

The first FWB I had was bent barrelled UPWARD just like the poster said concerning fixing barrel droop.  I could see by looking down the bore from the breech the slight curve of the bore upward.  I thought at the time it was what FWB did to get rid of droop!  Am I wrong? It was 1988 when I bought that first FWB.

The second FWB I got is the one I have now.  The bore is already straight with no upward bend, but I am convinced there IS some droop which the unique design of the rear sight system and surrounding unneeded metal fins aft the sight.  However, just recently I realized those fins there allow grabbing the gun from the middle all over the sight area without MOVING them!

The other thing is I think those fins aid in the barrel to piston breech for reinforcement.

I have been through a Lot of Colt SAAs whose barrels were off center for one reason or another to the fixed sights.  Some gunsmiths can BEND the COLT barrel to true the fixed sights!  I know, the idea of BENDING a barrel is gut wrenching.

[nced]

Hey Guys,
As part of an effort to get all my guns on the same page so to speak, I'm thinking of doing the following:

- Center all my scopes - so there dead center.
- Mount scope on rifle and see how much it shoots low.  I don't know if I've ever had one that shot high .
- Once I determine how low it shoots -> out-of-the-box, go to my padded wood vise and clamp the barrel down in the vise with its stock up.  Then slowly tweak the butt stock forward putting pressure to bend barrel upwards.
Do a little at a time and test the gun every few tweaks to make sure you're not over doing it.

In this way, I can remove most barrel droop without resorting to shimming the scope or making other adjustments to compensate for the fundamental issue - The Gun's barrel is drooping. 

Be careful using the stock to "tweak" your barrels because the pressure on the mounting screws MIGHT cause a split or "wallowing out" of the stock mounting screw holes in the wood. I also don't prefer to have bending pressure applied to the barrel pivot block and pressed in barrel, however I too have "tweaked" my barrels as you mentioned using my "barrel tweaking tree" at the shooting lane............


Anywhoo......as pointed out by another reply, I prefer to use a "bending fixture" that only applies bending stress on the barrel..........


I've been "tweaking my barrels" for years after having less than good results with tedious adjustable mounts of a few different brands. LOL.....I've never bent my barrels like this however.......