Help on barrel bending?

[Hoosier Daddy]

My new-2-me vintage Beeman C1 is shooting low....5" low at 10M with no hold-over.
It has a new Kruger 3-9X32 AO scope, I thought maybe it was defective so I swapped it with a Beeman 4x32 that has been fine on other rifles. Same deal.
Soooo, I swapped back the Kruger and put a .003 shim sandwiched with another layer of friction tape in the bottom of the rear ring. Now 4" and out of adjustment. 
  Standing back, looking at the barrel, I thought it had the dreaded Barrel Droop.
I took a straight edge and laid it on the barrel, turned it over and flipped it end for end... Yep, barrel is bent. 
 (In the pic I have a ruler to show the distance, but I used a true straight edge.)
 Problem is, the bend is close to the pivot block, about 1-3/4" away.
If it were the whole length of the barrel I would just support each end on wood blocks and smack it with my deadblow BFH in the middle.
  But being this close to the pivot block I will need to make a support and press some how. I know barrels can get bent "up" here from pulling the trigger when open and slamming shut, but mine droops down. I suspect from years (decades) of breaking it open. The barrel length on this C1 carbine is only 10-3/8" but it has a very FIRM lock-up, so you really have to palm smack it to breaking open.
 Also, the cocking linkage is pinned to the block, not screwed or bolted so while I can remove the stock, I would like to do it with the action assembled.
 - What have you used in such a case?
 - How do you know how far to go?
 - I assume baby steps, test firing each time but am worried about stressing the steel barrel making it weaker to bend again, or am I being paranoid?
 - I am sure there will be some spring back so thinking it would need to go "over-center" in the jig?
 I have an assortment of work benches, wood blocks, vices, C-clamps, Beam clamps even a Pipe clamp,  so anything home made I can probably fab up.
 I have "searched" the topic and nced did something like I am thinking except mine would need to be off set, not centered. (thanks Ed)https://www.gatewaytoairguns.org/GTA/index.php?topic=68011.msg155778015#msg155778015

 If you made it this far, thanks for your consideration and let me hear your methods other than "putting it in the fork of a tree and pulling".   
LOL!

[mikeyb]

I don't think "normal" cocking can cause that kind of bend. IMO someone either over-cocked it REAL HARD, or something inside (broken spring?) locked up solid during a cocking stroke.

I've modified the "UTG Compensator Mount for RWS Airguns" to work on any dovetail. The 17.1" upward compensation at 30 yard rating equates to 5.7" at 10 yards. Alomst perfect for your situation?
Out of stock now, but I got one from Amazon 

I had to rebuild my Dodge rear end a couple years ago and needed a serious press to remove and install bearing races. I got this on sale for about $140 and it saved me several hundred dollars in bloated garage part prices and their labor.

https://www.harborfreight.com/20-ton-shop-press-32879.html

I recenty straightened a very bent 1" diameter solid steel bar, so I know it will EASILY bend an airgun barrel.

I would use nced's fixture if the bend was roughly centered. Less chance of over bending or other damage. In your case I would build some temporary 2x4 support for the longer barrel section and the block area. Then I'd clamp it into position on my hydraulic press and slowly try to straighten the barrel.

I'd check progress with a straight edge and visibly looking down the bore. Knowing that there may also be barrel droop due to a tiny lockup angle, I might over-bend it a very small amount so my scope settings would be close to zero when sighted in.

[Hoosier Daddy]

Similar thoughts Michael...
Although I think your 20 ton may be over kill! LOL
I do have a 2 ton bottle jack as well. 

[Techie]

I think most people are way too scared of barrel bending.  Just stick it in the fork of a tree and pull.  I've done this several times with the stock still on to get leverage, and I've been fine.  No, I didn't break the stock.  Now I'm no longer scared of doing it.  Not really a big deal.  Do it a little at a time.  5 minutes later your problem is solved.  Just don't go full gorilla on it.

[Roadworthy]

Your actual bend may be near the barrel block but you don't really need to worry about straightening the barrel at that point.  Bending the barrel at any point may be used to offset the effect of the downward bend.  Yes, it would be ideal to remove the problem but for shooting purposes it's only necessary to compensate for it.

[Hoosier Daddy]

Thanks guys... maybe I am over thinking this.
I appreciate the input!

[Novagun]

The straight edge you show is a wooden ruler. They are often warped so maybe recheck with a better straight edge.
I have straightened barrels a good few times. I use a piece of pipe padded where it touches the bluing. Grip the breach block in a vice padded with hardwood blocks or similar. Grip directly against the force you intend to apply. IE not gripping the cheeks. Slip the pipe over the barrel and swing on it. It takes a fair bit of force. Bend -- test fire -- bend again until you get it right.
Similar to the fork of a tree method. Provided you go at it gently you will make a good job of it.

[Nvreloader]

Hey Scott

Just do a open bbl dry fire, it just may be enough............ to bend it up,  LOL,    I am joking of course about the dry fire.

Nced bending jig would work, but I would have a longer support on the muzzle end,
place 1 support right up next to the bbl block and the put the eye bolt ring on the bend high point,
and supported about half way down the bbl, and apply pressure.

Keep doing/adding more pressure until you can see the end results you need,
I would center the scope and hopefully you can leave the scope attached while bending,
then you can shoot to see your results from bending etc.

You can also use these rings, I have 2 sets now in use,
they provided over 32"+ of adjustments at 25 yds with a centered scope,
https://www.ebay.com/itm/Monstrum-Tactical-1-inch-Adjustable-Height-Scope-Rings/163724469362

Tia,
Don

[Airnut]

I have fixed many a barrel its really no big deal if you take your time.
I always remove the barrel and clamp the breach block in a padded vise.Then used a strait edge to determine the way it needs to be bent then pull the end of the barrel the way it needs to go. Its funny but most of the time you will feel it when it moves back were it should be. You really need a vice thats firmly attached to a heavy bench.  Its hard to over bend it by hand. If your barrel is real short you may need a padded pipe to go over the end of barrel to gain extra leverage. Check the barrel before you reinstall.
I know its scary the first time you do it but you will be fine. 

[lizzie]

I used my homemade barrel-bending tool, which is essentially a piece of 2x4 with a series of eye-bolts and U-bolts.
I made it years ago when  I bought an old Diana model 34 that had what sounds like the same type of bend/ locations as your gun.
 Trying to describe it so that it makes sense, I place the barrel through the series of "eyes" and adjust tension wherever needed to create a difference in curvature anywhere along the barrel length. I do use some leather strips to pad the steel barrel from direct contact with the bolts, just to help insure that there are no scratches from using the bending tool.
If this makes no sense, let me know, and I'll take one of my guns and place it in the tool, as if I a going to actually use it....just as a visual demonstration.

[Chouchin66]

@ Hoosier Daddy, due to hand slip on cocking,I got the reverse effect of what you have. The bending fix I used was near copy of one Tom Gaylord built; it uses a "C" clamp & wood block spacers. Very, Very Easy & controllable! He did a blog on it @ Pyramid Air... Highly worth a look ! Good luck Pal !
- Chris

[DanD]

I think most people are way too scared of barrel bending.  Just stick it in the fork of a tree and pull...

Heck yeah.

[Hoosier Daddy]

The straight edge you show is a wooden ruler. They are often warped so maybe recheck with a better straight edge.

Hugh... I specifically said in my original post I used a straight edge, I turned it over and flipped it end for end.  The ruler was solely for measurements sake.

 Folks.. "Scared" ain't the word. "Terrified" is more like it.... I just bought this vintage gun and a replacement barrel is scarce as hens teeth!

 So... I used some oak blocks cut to size under the pivot block. Clamped them to the pivot and braced the end of the barrel with a selection of various width pieces of wood and began clamping with a beam clamp.
 All the while singing "For He's a Jolly Good Barrel"...
 After 3 attempts of what I feared was too much, twice at the pivot and once in the center, I only gained an inch. 
More power is needed.
I wish I could think of a way to mock this up in a rotating fixture with my dial indicator on the end of the barrel to check run-out and get it centered.

[Warburrito]

Great luck that this is being posted today...I noticed that my other barrel for my Beeman Kodiak is bent to the right and need to be corrected.  Went to switch my barrels and noticed the barrel cocking aid at the end wasn't perfectly in the center.  I removed it and placed it along the edge of my 2 ft level and found it was definitely curved.  I could see light in the middle with both ends touching then at the ends when rotated.  Not sure how it happened while it wasn't even attached, but I guess Ill never figure that out.

Thanks guys!

[Nvreloader]

Scott,
Per the info below, Was that 1" gain, at what range, is your scope centered?

Your bending jig looks OK, except for the bottom bracing, may need a HD steel bar?
A big "C" clamp clamped right next to the bar clamp and continue on, in little tiny steps..............

"All the while singing "For He's a Jolly Good Barrel"...
After 3 attempts of what I feared was too much, twice at the pivot and once in the center, I only gained an inch.  "


Following along.........
Tia,
Don

[lizzie]

https://www.gatewaytoairguns.org/GTA/index.php?topic=22932.20


The U-bolts are used for holding the breach block, the three eye-bolts on the opposite end held the barrel end, and the adjustment was made with the remaining bolt. The barrel will need to have tension applied in what seems like an excessive amount.
I just applied tension...let it sit overnight. Checked the next morning....kept turning up the tension for a couple more days until the barrel was where I wanted it.

[eeler1]

Aim high?

There’s this;   

Keep in mind if you bend it too far, you can always bend it back.  If barrel bending was from cocking, then a lot more barrels would be bent.

[nced]

My new-2-me vintage Beeman C1 is shooting low....5" low at 10M with no hold-over.
It has a new Kruger 3-9X32 AO scope, I thought maybe it was defective so I swapped it with a Beeman 4x32 that has been fine on other rifles. Same deal.
Soooo, I swapped back the Kruger and put a .003 shim sandwiched with another layer of friction tape in the bottom of the rear ring. Now 4" and out of adjustment. 
  Standing back, looking at the barrel, I thought it had the dreaded Barrel Droop.
I took a straight edge and laid it on the barrel, turned it over and flipped it end for end... Yep, barrel is bent. 
 (In the pic I have a ruler to show the distance, but I used a true straight edge.)
 Problem is, the bend is close to the pivot block, about 1-3/4" away.
If it were the whole length of the barrel I would just support each end on wood blocks and smack it with my deadblow BFH in the middle.
  But being this close to the pivot block I will need to make a support and press some how. I know barrels can get bent "up" here from pulling the trigger when open and slamming shut, but mine droops down. I suspect from years (decades) of breaking it open. The barrel length on this C1 carbine is only 10-3/8" but it has a very FIRM lock-up, so you really have to palm smack it to breaking open.
 Also, the cocking linkage is pinned to the block, not screwed or bolted so while I can remove the stock, I would like to do it with the action assembled.
 - What have you used in such a case?
 - How do you know how far to go?
 - I assume baby steps, test firing each time but am worried about stressing the steel barrel making it weaker to bend again, or am I being paranoid?
 - I am sure there will be some spring back so thinking it would need to go "over-center" in the jig?
 I have an assortment of work benches, wood blocks, vices, C-clamps, Beam clamps even a Pipe clamp,  so anything home made I can probably fab up.
 I have "searched" the topic and nced did something like I am thinking except mine would need to be off set, not centered. (thanks Ed)https://www.gatewaytoairguns.org/GTA/index.php?topic=68011.msg155778015#msg155778015

 If you made it this far, thanks for your consideration and let me hear your methods other than "putting it in the fork of a tree and pulling".   
LOL!

I've been bending my HW airgun barrels for years so the poi is within 1" or so at 30 yards after optically centering the scopes and fine adjustments are done with the turrets. Here is the construction lumber, steel eye bolt, Delrin shoe, flat washer and nut contraption I've been using for a few years now...........

I always place the end of the "barrel tweaker" against the barrel pivot block so no bending force is transferred to the pressed in barrel/pivot block joint. Also, if the barrel is bent too far it's easy to bend the barrel in the opposite direction since the "pressure point" is always at the same place along the length of the barrel. Here is the bending sequence I used with the new HW95 barrel I bought on sale from that Canadian retailer when they stopped selling hW parts a few years ago.........

There are times when it's a bit more tedious to "put the poi where wanted" but with patience it has always worked. Matter of fact, a bend in an airgun barrel that moves the poi 4" at only 18 yards can't be seen with the naked eye!

[ezman604]

Check out this oldie...

https://www.gatewaytoairguns.org/GTA/index.php?topic=49873.0

[mpbby]

Scott, first of all, you have to center your scope.  I think that what really matters (to better support the erector tube) is the 'mechanical' center = clicks divided by 2, instead the mirror method that usually gives relevant differences.

After that, you have to be patient to follow your own planning = baby steps, checking again.. The barrel will resist fine, don't worry.

Yes, there is the 'spring back' and you will have to make it.. 'strong' (trying to keep the baby steps).   

Just to let you know, Hawke has inserts (plastic) that give a vertical effect.



Marcos