Fixing a barrel with a tight spot in it.
I have this 25 LW barrel and it has some problems.
It shoots Kings very well, but perhaps I should define what that means to me. 35 yards 1/4 to 1/3 inch, 50 yards 1/3 to 3/4 inch, 100 yards 4 out of 5 around or under an inch with a flyer and at times well under an inch for all five shots.
But I can’t hit my ass with both hands with any other pellet, and that includes the vaunted Predator, which is a distant 2nd place, being as the groups are 3 times larger than the Kings, not really bad, but not real good either.
I have tried, Kodiaks, Benjies, all weights of Jerrys slugs, EJ’ and Predators to no avail in my quest for accuracy with anything other than Kings
I can’t in good faith sell the barrel to someone else, unless they have a cheap supply of Kings and don’t mind shooting Kings exclusively.
I have tried different frames, springs, hammers, breeches, scopes, pellets, but they all shoot lousy except the Kings, and then only with the stock spring, breech and hammer assembly and only below 1000 FPS.
I am not using a LDC, if I did it would make no difference.
Some would say I should leave it as is, but a 22 Condor can shoot Monsters of the same weight at the same velocity and have a better BC and SD.
So here is what I think is the trouble:
When I push a pellet down the bore with a cleaning rod, the first chambering section or what most call the “lead”, the pellet goes in very easy, pushing it further it gets tight as it goes thru the machined down section that the breech rides on, then it free falls under the weight of the cleaning rod to the last 3/4 inch or so that comprises the choke.
That “lead” part will let the pellet fall out of the breech, if you decock the rifle and then cock it again, annoying but I doubt if that is the trouble.
The fact that it gets tight in the machined down section the breech rides on, tells me that area was choked down during the maching process.
When the pellet is blown down thru that restriction, because it is moving the air does not force it to open the skirts again because the pressure is less as it goes into the 20 inch or so loose part,as a result it does not re-expand to fit the loose part and is rattling down the barrel until it hits the choke.
With Kings it is different, they have such a thin skirt, that they re-expand in the loose section of the bore and do not “rattle” down the tube like other pellets do.
To fix it I believe I have two options:
I can have the breech section cut off and a new breech and lead machined on the barrel which will make the barrel shorter. Or I can lap that breech section and make it match the rest of the barrel except the choke.
If I have it cut and remachined it is a one shot chance. If I lap it and it does not work or ruins that section, I can still have it machined.
I have considered getting fine polishing compound, rolling a lead slug in it between two sections of glass to embed the compound, using two cleaning rods, one in the muzzle, one in the breech. With the two rods in contact with each end of the slug, tapping it to bump it up in diameter until it is tight, then pushing it back and forth with the two rods inserted in the muzzle end and breech, and repeating until I get the tight spot the same diameter as the loose portion of the barrel.
Or I can just put some polishing compound on a patch and use a pistol rod to lap the breech area.
Any ideas on how you folks would fix this?
If I choose to remove the breech and redo it, who can do this and has the time?
Regards,
Roachcreek
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my 2 cents
Yeah, you can find the best ammo for an average barrel (and RC already has) but that does not mean it’s OK for a barrel to be tight, loose, “F’in tight”!
If you were designing the perfect barrel, you might decide that a tight choke at the muzzle was good (assuming you were shooting pellets or suspect ammo) but there is NO reason you would make the barrel with chokes at both ends!
22 Powder Burners – you shoot different ammo until you find the one it likes and then buy a few bricks.
my 2 cents
I’ve been thinking a lot about this post because I discovered the same situation with my barrel ( tight, loose, f’n tight).
Doesn’t the edgun use LW chocked barrels without the breech end turned down. Has any of our members pushed a pellet down the barrel of theirs and found a different scenario?
I personally would logically think heat produced from machining would have an expanding effect rather than a restrictive one. If coolant is used then heat should not be a factor in this.
If it has to do with molecular structure, this ironworker is not educated enough to turn one down without it happening again unless I had multiples to experiment on. Pretty expensive idea.
Maybe someone at LW can shed some light on the matter.
Noid,
I sure did try them, they did not work unfortunately.
Thanks,
Roachcreek
Have you tried benji domes?. They shoot as good as kings in my condor they are 27.9 gr and are fantastic as far as constancy in weight out of the tin. I weighed 3 tins and figured out I was waisting my time. The skirts are slightly thicker than kings but they are still thin IMO.
These are lessons I have learned more then once 😀
Wok,
That is the danger isn’t it.
Originally I got the 25 barrel to shot heavy projectiles as fast as I could.
But it would be nice to at least shoot Predators, but the skirts are too thick on even them to shoot well.
Perhaps I will just keep it as it is.
regards,
Roachcreek
I do not know if LW did this or the machinist who bought them and turned it down, I suspect the latter.
When you push a pellet down the barrel, it is very obvious that that is what happened, it constricted while turning the breech.
Jerry, your right about the abrupt choke, it is in the last inch or so and right now it gives me that Smooth twist barrel effect I have joked with you in the past about on this barrel.
But like I say it shoots Kings very well.
I am thinking about lapping that first 3 inches or so with lapping compound from wheeler and using a lead lap to do it and push it back and forth with two cleaning rods.
I am afraid that fire lapping would just increase the overall dimensions.
Roachcreek
Do you not like shooting kings out of it? If you do are you willing to risk screwing with the barrel until it no longer shoots them well?
Guys,
I do not know if LW did this or the machinist who bought them and turned it down, I suspect the latter.
When you push a pellet down the barrel, it is very obvious that that is what happened, it constricted while turning the breech.
Jerry, your right about the abrupt choke, it is in the last inch or so and right now it gives me that Smooth twist barrel effect I have joked with you in the past about on this barrel.
But like I say it shoots Kings very well.
I am thinking about lapping that first 3 inches or so with lapping compound from wheeler and using a lead lap to do it and push it back and forth with two cleaning rods.
I am afraid that fire lapping would just increase the overall dimensions.
Roachcreek
Greg –
here is the link to the article. I took another look. Not only does it say hammer forged barrels tends to constrict bore diameter when machined, it also says button rifled barrels expand the bore. The residual stress in the metal does strange things.
This means this constriction was either the result of a machining problem or was in the blank to begin with. I have read where some match barrel manufacturers advise you to discard a couple inches from the end of the blank when finishing the barrel. Maybe that did not happen here. Without any objective basis for this guess I am guessing this breach constriction is the result of a machining flaw.
http://technology.calumet.purdue.edu/met/higley/rmfireHammerForgedBarrels.pdf
It has a very tight choke at the last 1 inch or so of the muzzle, I think they turned it down too fast and choked the breech also.
Roachcreek
sorry i must have read over that ….. 😳 😳 ….but you are correct in thinking that dull tooling or too heavy of cuts would collaps the bore a bit.
tom-
that is good info to know thanks..
Greg
LW button rifles, BSA hammer forges (or did).
I be rid of the choke because the objective is to make big power and that means shooting heavy bullets not light skirted pellets. A little choke might be OK but a tight choke is just a crutch for bad pellets. Most quality pellets these days don’t need a choke to be tight. I had a Sumatra with a tight and pretty abrupt choke and it shot poorly. I cut the choke off and it shoots much better now.
I dont know how LW makes their barrels, so I dont know if this is a factor. I read an article where they were comparing stock ruger 22 barrel to match grade item. In that article they mentioned that when you machine material off a rugers hammer forged barrel it will cause the dimensions of the bore to tighten up – essentially create a “choke”. At the level of competition these guys were at this is evidently common knowledge. In the article they used this tendency to their advantage by turning the muzzle end. This both gave them a choke and allowed them to install a tuning weight.
If its not obvious – here is the point. If LW hammer forges the barrel then cutting and turning the breach might give you exactly what you have now only shorter. What this does not explain is why LW did not compensate before shipping the barrel. In match grade items this attention to detail should be expected. This should never have left the factory this way. Was this an after market barrel? Maybe somebody other than LW finished the barrel and did not correct for the choke effect.
Why no choke Jerry?
John
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Does LW do the machining of the breach or do they just supply blanks for builders and manufacturers?