The not bent, bent barrel puzzle

[ggggr]

I think the engineers on here may sort this one out. I have been having a tinker with a rough Bsa cadet. I noticed that the barrel pivot pin took a bit of shifting when the gun was stripped. Anyway I tinkered with the gun and put it together (pin was a bit awkward to get in) and tried a few shots ( still waiting for foresight). I noticed the barrel was bent to the right. I looked at it and had a go at straightening it and it still looked to the right. I sighted down the breech block and thought it looked pretty good so thought maybe the jaws are bent. Jaws were not too bad and the pin would go through the empty jaws ok. I noticed the hole in the breech block was a bit damaged but this is fairly normal on cadets when the barrels are fitted with the cocking arm still on. I did a little bit of easing with a fine file so I could get the pin through ok but the barrel still looks a little bit to the right. SO--as come across this on a few old guns, I reckon that if the pin goes through the empty jaws ok then they and the pin must be ok, which means that the hole in the breech must be at a slight angle. I assume too much pressure was put on the drill all those years ago and it deflected at a slight angle and then a bit of "brute force" was used when putting the gun together? I suppose the engineers would weld the hole and re drill or drill the hole larger and put in an insert? pretty sure this will plink ok so it is not a problem for me but I thought I would share my thoughts/ask for info on here

[flatrajectory]

OK,
If it is a rough gun then use it as is , as both front and rearsights are attached to the barrel it will still shoot straight.
If it annoys you have the jaws/barrel pivot hole re drilled on a bench drill press then weld up any gaps.

pp

[edbear2]

Hi Guy.........I have not seen this on a BSA, but it is common on Haenel break barrels.....I have seen it on both 302's and 303's, one being a little used sleeper.....It is disconcerting at first, and I removed the barrel to double check....all was straight / square, and all seemed well, but there was a definite effect of the barrel not being dead in line with the cylinder when eyed up from behind.......that said, the barrel was perfect in itself, and looking through the sights you did not notice the effect, and as the previous poster said shooting was unaffected (in fact it was really accurate).

[ggggr]

Thanks to both of the above gents. (I knew Ed would be along ). It is not a problem for me plinking and like has been said, if both sights are on the barrel should not really matter. I was just wondering if any other people have come across it,the reason for it and, should you want to cure it, the cure. I spent about 2 hours one Sunday night stoning the pivot bolt on a G35 to get it to fit ( same problem,bolt would go through without the barrel in place but not with it). I think that maybe one Friday afternoon that Jock clamped the jaws up and Hamish belted the bolt through, thinking "it will be a few years before someone strips this down".
Just a thought---would a taper reamer sort this out?

[hwvixen]

I've heard it called many things Guy...but never that..must be a "smiths" term for bashing the bishop...

[ggggr]

I've heard it called many things Guy...but never that..must be a "smiths" term for bashing the bishop...

Behave or you will get them started with "polishing the piston,or mainspring etc", "honing the cylinder", "lubing my weapon" and thats before they start asking about what lubrication you get and talking about penetration.
Mods feel free to snigger and delete this post

[air-tech]

Just a thought---would a taper reamer sort this out?

No it would simply follow the angle of the existing hole.

You would really need to drill out a hole that is square to the cylinder just slightly oversize. But not with a twist drill. Again this would follow the hole. Unless maybe a really shortened one perhaps, with a rather flat angle to the cutting face? Ideally however you would need a form of milling cutter, engineers can fill in.

Then, an oversize pivot bolt fitted obviously after opening out the breech block too.

[bluesman]

Years ago(45 approx)I bought a new Meteor with the same problem.It was so bent the rear(adjustable) sight was as far over as it would go.Too young and gullible to take it back!

[Phil Russell]

Check the jaws on the cylinder. My first layperson check would be to find a nice straight steel rod that would go through the jaw holes in place of the pivot pin without wobbling .. barrel not attached. Check that said rod was at 90 degrees to the cylinder etc. in all directions. Any slight deviation would throw the barrel off line. Do the same for the barrel to check the hole is at 90 degrees to the breech face.

As said above, if there is any inacurracy, it may be possible to get the errant hole(s) redrilled and a new pin fitted.

Cheers, phil

[ggggr]

Check the jaws on the cylinder. My first layperson check would be to find a nice straight steel rod that would go through the jaw holes in place of the pivot pin without wobbling .. barrel not attached. Check that said rod was at 90 degrees to the cylinder etc. in all directions. Any slight deviation would throw the barrel off line. Do the same for the barrel to check the hole is at 90 degrees to the breech face.

As said above, if there is any inacurracy, it may be possible to get the errant hole(s) redrilled and a new pin fitted.

Cheers, phil

I thought of the long steel rod to check the jaws and the hole in the breech block Phil ( not gone one handy) but I cant see the jaws being far out if the pin goes through without the barrel in place. It must be the hole in the breech block. Oddly, the (slightly filed) pin goes through better from one side than the other. Ie goes through left to right ok but seems a bit out from right to left, which is the way I usually put them in. I dont see this beig a problem for plinking and not worth the expense of an engineering job and oversized pin. If anybody notices it I will just tell them it was like that on the fairground

[torrens]

Hi ggggr, like edbear2 I had (and still have) a Haenal 302 with a barrel pointing off right a smidgen, to the extent that a 'scope won't adjust enough to zero. The breech was machined a fraction out of line, (maybe a machinist with a schnapps hangover?) but it is notably accurate with open sights so no problem . Think of it as a touch of right cast like posh shotguns have.......
atb torrens

[ggggr]

I thought i would refresh this. I now have a Webley falcon with the same thing BUT on this one the barrel pivot goes through no problem. This must mean that both jaws are bent at an angle to the cylinder. I have moved the sights and the gun plinks ok (this is the one that had rust in the barrel). When I spoke to Red Bob the other day, he mentioned he had a cadet major with the same problem. I wonder if with some of the older guns that the guns have fallen over and bent the jaws?

[magicesperanto]

Is it possible to fit the barrel upside down and see which way (if any) it leans?

May be interesting to see how the pin holes line up like that, and should tell you what part or parts are out of plonk.

[flatrajectory]

I have seen many air rifles with bent /mis aligned breech jaws, usually caused by the rifle being fired whilst the barrel was in the open/cocked position. This causes the jaws to get bent as the barrel slams shut under the force of the mainspring. Most cases can be rectified in the workshop.

Pete.

[Phil Russell]

I thought i would refresh this. I now have a Webley falcon with the same thing BUT on this one the barrel pivot goes through no problem. This must mean that both jaws are bent at an angle to the cylinder. I have moved the sights and the gun plinks ok (this is the one that had rust in the barrel). When I spoke to Red Bob the other day, he mentioned he had a cadet major with the same problem. I wonder if with some of the older guns that the guns have fallen over and bent the jaws?

Hi Guy
Just found your old thread. Just to say that I have a MK1 Hawk with the same fault. Just noticed it ... .177 barrel with a slight right bias. At first I suspected the barrel but the effect is the same with the other (.22) barrel as well. No play in the breech and the breech moves smoothly. So I must assume that the jaws were not perfect from new. Indeed, by using various straight edges I have convinced myself that I can detect a 'breech jaw misalignment' fault ... i.e. a slight bend of the jaws that takes them out of line with the rest of the cylinder. I cannot see how the rh bias could have arisen due to an accident as I suspect the barrel would have been damaged before the jaws.
Maybe it was a Friday rifle ... still shoots quite nicely though.

I guess that brute force could be used to correct it, but I suspect that, in doing so, it might result in the pivot bolt holes becoming misaligned. So ... leave it alone.
Cheers, Phil