Is this a problem?

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Hi Rob,

No, it is not a problem. I have seen better and I have seen worse....just be sure that the nut on pivot bolt and the bushing is well lubed and has some Loctite 242 (blue) on the end of the pivot bolt threads!

A properly tightened barrel will stay in any position that you put it in AFTER it is cocked. Here is a little run down on doing that just to be clear.

1. Lube the pivot joint parts as I have described above.

2. I like to use JM moly and clear tar mixed at a ration of 2 parts moly to 1 part clear tar and pack the grease cups at the breach block.

3. Attach the barrel/breech block to the yoke and don't forget the Loctite 242.

4. Tighten the pivot bolt until it is just snug.

5. I sit in a chair with the butt of the gunstock sitting in between my knees. I cock the gun...then I take a screwdriver and give a TINY sung-up twist on the pivot bolt.

6. I then lift the barrel until it is at a 90 degree angle (sticking straight out to the right or left)...when I let go of the barrel, IF it starts to move, I give the bolt another TINY little snug-up twist. What I am trying to accomplish it to get the pivot bolt JUST snug enough that I can cock the gun and THEN take my hand and move the barrel to any position that I wish and have it NOT MOVE....if it moves when you let go of it it's TOO LOOSE.

If you want me to post pictures to make things clearer, just let me know and I will!

Sincerely,

-Curtis

You're a great help.
If you have time, and you don't mind, please do post some pics. I'm a new air gunner and I want to do things right.
Thanks again for the info. I thought I'd have to send this gun back. It shoots very fast for a .22.
Rob

I'm not real sure what a properly tightend barrel pivot has to do with an off-center bore but...........
Yes, an improperly centered bore could be a problem. Is the muzzle end the same? If the bore is not made so as to be aligned with the sights, and especially the scope rails, you'll have problems zeroing the gun. If its that far off, you might run out of adjustment before you get the sights set. It could be that its just the breech end thats a bit off, with the rest of the barrel being fine. The important part of the bore that really needs to be aligned correctly is the last inch or so, the rest is really irrelevant. As long as the transfer port is lined up, the sights work ok and the gun shoots where you want it to, I wouldn't worry about it. If the gun shoots hard, thats an added bonus.

I returned mine back to PA I thought it was a defect.

Looking at the circular mark left by the o ring, it appears that the transfer port still lines up with the bore so that the air flow has unrestricted flow.
It looks a bit off putting but it is nothing to worry about and I imagine it is well within the makers manufacturing tolerance.
Bottom line is if it is shooting accurately and on full power, it is OK.

Rob,

Gosh dang it....

A few days after you originally posted this message, a gentleman posted a message to start a new string concerning problems with his breech. I posted a picture for him and I think that I overlooked getting back to YOUR post (this one) as I did have a vague recollection of posting the picture for the other fella....

I sincerely apologize for the mistake!

SO let me start this long overdue reply by posting a picture of the breech of one of my .22 caliber 350 Magnums.

As you will see in the photo of my gun's breech, the bore axis is not perfectly concentrically centered in my gun either. This is not unusual by any means for a break barrel regardless of the make and manufacturer....and the cost of the gun is of no consequence either; I've seen this occur in cheap junk guns and in $1000+ guns alike.

Here is a pic of one of my 350s




If you look at the link below, the gentleman who was asking for help, the one that I posted the pic for, had a 350 Magnum that did not have the leading edge of his breech chamfered AT ALL....none....zip....nada! This was obviously an oversight at the factory....the point is that if you look at the pictures of HIS gun that he posted after he resolved the issue himself, you will see that the bore axis of his barrel at the breech is not perfectly concentrically centered either.

http://www.network54.com/Forum/184474/thread/1215061236/last-1215236484/RWS+350+Magnum+pellet+seating+problems-


david - (Login dvdrit) who just posted here toady....

.....is 100% correct when he said," Looking at the circular mark left by the o ring, it appears that the transfer port still lines up with the bore so that the air flow has unrestricted flow.

Ok...I think that it is safe to say that the issue that was of a concern to you can now be classified as a "non-issue".....

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Now I want to explain to you why I mentioned the barrel pivot joint issue and keeping it tight (appropriately tight).
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I am not referencing the david (Login dvdrit) who just posted a reply TODAY, but rather the other gentleman, DAVE, that posted on June 28th .

He indicated in his post that he didnˇ¦t see what a properly tightened barrel pivot has to do with an off-center bore.

Well, I want to take a minute (or a hundred) and try to explain why I mentioned it but first I am going to point out some things for other people to consider who might read this in the future....

As david (Login dvdrit) so correctly observed, there are markings around the air transfer port that tells us a complete story....Good eye david !!!!!!!!!

As I first stated back on the 28th of June, the alignment of the bore axis is not an issue in this case...having repaired and tuned more break barrels than I care to think about in the last 20+ years, I have seen the same thing time and time again - sometimes even worse - much worse in fact - in many different guns - not just different models but different makes as well regardless of the price of the gun.

In this case, a picture is worth MORE than 1000 words.....it always helps so much to have pictures if the gun is not available for evaluation....good job Rob!!

When we look at the pictures that Rob provided, we see that surrounding the air transfer port is 2 distinct prints. The larger is where the breech seal O-ring is coming into contact with the outer end of the compression tube at the air transfer port ˇV right between the arms of the yoke. The second is residue created in the firing process and gives us a clear image which tells us EXACTLY where and how the breech is lining up with the air transfer port. I donˇ¦t see any problems in that area at all...I WILL say that I am a bit of a major nit-picker and I use a paper towel and wipe the residue off from between the yoke arms before I put the gun away after some shooting.

When I have received a gun where the breech does not appear to be perfectly centered at the rear of the breech block, I check to see if the bore axis is concentrically centered in relation to the muzzle at the crown; if it is then there is not an issue.

In regard to the advice on making sure that the barrel pivot joint is properly adjusted, I have had to repair far too many guns that incurred damage to parts because the pivot joint was too loose. Additionally, I have had guns sent to me where the owner complained that the barrel was not able to be "broken open" at all or that the barrel had become almost impossible to ˇ§break openˇ¨ and accuracy and power levels had dropped to unacceptable margins....these related problems were due to the barrel pivot joint being much too loose. This condition would most certainly have a negative impact on any gun as the pivot joint becomes looser and looser, that is a forgone conclusion.

When the barrel pivot joint loosens to the point that there is physical shifting of the breech block, what happens is that the detent forces the breech block (and the barrel) into a hyper-extended position where the face of the breech block, and the bore breech too of course, is no longer flush with the flat surface between the yoke of the compression tube where the air transfer port is located....to give you a mental picture that is easy to deal with....when this happens, the muzzle would rise up higher than it should....it would generally be such a slight rise, that the human eye canˇ¦t see the change unless it is measured with a gauge or if there was a reference point that was not attached to the barrel to give a visual indication of the "degree of rise" so that they human eye can identify it.

In addition to the aforementioned issues with a barrel that can be hard to "break open / won't break open", there can be issues resulting from a misalignment of cocking linkage parts AND the parts that they interact with. The result is that there is undo stress on the cocking linkage and related parts because of the change in the geometric alignment between the point at which the cocking linkage attaches to the bottom front end of the breech block and where it makes its next contact point. Some guns have a single cocking arm and some have 2 cocking arms which are attached at their own jointed pivot point, but regardless if it is a single arm or if there is two, when the geometric alignment of these part(s) changes, stress is exerted in ways which are detrimental to other parts that they interact with or upon due primarily to force being exerted from an inappropriate and incorrect angle.

A prime example of this can be found in the 350 Magnum which has two linked cocking arms.

If misalignment causes a change in the geometric relationship between linked parts, applied force sourcing from an incorrect angle will be exerted on the linkage where the first arm joins to the second arm...when this happens, the spacer/roller wheel that is located at this joint can bind as it is not well lubed and properly finished right from the factory anyway and is most probably already bound. This can and usually will cause varying degrees of galling on the bottom of the compression tube which is common in 350 and some other guns. Additionally, the "shoe" end of the second cocking arm can be forced to rise higher than it should thus forcing it up into the piston sleeve (spring cover tube) during cocking and/or cause the "shoe" end of the second cocking arm to improperly engage the piston during the cocking stroke and become damaged due to improper ware....neither of these things are good for the parts and should be resolved if it is happening...preventative maintenance is the best solution ˇV and there is yet another reason for my original "helpful thoughts" that I wanted to share with Rob!

Oh....here is a picture of some deep galling on the bottom of a compression tube from a 350 Mag that was a result of two things:

1. The spacer wheel at the pivot linkage between the first and second cocking arms was NOT rotating freely and smoothly.
   
2. The barrel pivot joint was much too loose and was forcing the spacer wheel up into the bottom of the compression tube with MUCH too MUCH force...remember what we learned about proper geometric alignment of parts!?!?
   

Also, there are, potentially, further alignment issues that could arise from a barrel pivot joint that was not properly tightened and adjusted considering that the pivot point in break barrels is at the bottom front of the breech block, but let it suffice to say that the breech block should be SNUG in the yoke of the compression tube on EVERY BREAL BARREL GUN!!

So the point of mentioning be sure that the barrel pivot bolt tight is this:

#1) That is an area that has a high degree of affect of many different aspects of how a break barrel performs where accuracy and efficiency is concerned.

#2) If that pivot joint is too loose, it can cause parts to wear in areas where they should not.

#3) It is just damm good FREE advice and MOST people do NOT know what a properly adjusted break barrel pivot joint should be like.



Well....I have shot my big mouth off enough....time for coffee and a smoke

Good luck and good shooting to all

-Curtis

Your efforts are greatly appreciated. I am very fond of this little rifle. It's a .22 and shoots CP lights nearly 700 fps. It's easy for an old man like me to carry through the woods for miles. So thank you again for the information you supplied. It will not go unstudied nor unused.
Rob