A case for the .750 tenon on a RFBR rifle!

[stiller]

Jerry, thank you for bring your knowledge and experience to the conversation.

Your points are well taken:

1. more face contact and
2. less tightening torque distortion.

Do you see this to be a problem with many RFBR .900 barrels?

The ones I see don't take much to break them loose.

The take away here is don't over torque the barrel.

If you don't mind saying what number do you torque barrels to.

TKH

I torque mine to 350 inch lbs. I noticed at 500 I could feel it slightly on a slug or a pin. At 250 I noticed flyers. I think 400 is the most we can go without pinching. BTW, the bore gets smaller at the junction, not bigger. The whip of a barrel even from our small vibrations can unload on the top and bottom sides at too loose of a torque (ask me how I know). On a centerfire, I used at least 100 ft-lbs. A very successful BR shooter was having flyer issues with barrels "snap" tight. After I talked him into tightening them up more, it went away. I built a prototype Trident action once with 0.875-32tpi in it. I then seated it on the bottom of the bore rather than on the face. It worked really well and I should probably use it. My barrel testing philosophy doesn't work very well with it though, as all my barrels that I pass on need to fit production actions.

I really feel 0.900 is the least we should use. The action cbore is about 0.755, the radius into it is probably another 0.005. Given that, the id you can push against is 0.765 best case. At a full 0.900 you now have about 0.065 all around. Debur the barrel shoulder edge any and you have less yet. When I do a Ross or R0 taper, I relieve the shoulder from 0.750 out to 1.000 so I have a ring at the outside of the circle. That way you get the radius offset from center to counteract the whip motion.

[stiller]

In the not too distant past anyone but a barrel maker who lapped and admitted it was chastised and called an idiot for doing it, how dare anyone even touch the inside of their barrel. Its good to see others doing it, talking about it and not be crapped on for mentioning it.

Pete

Who says we don't get crapped on? BTW, most people really don't need to be doing it. Until you have done a good number of them with a correct procedure, most likely you will just eff it up anyways. I probably did 50 or more until I felt really comfortable doing them and not questioning my job.

[tonykharper]

I had Killough build the rifle and it came with Ross taper Shilen barrel Gorham chambered for it. The rifle didn't shoot competitively, really. After some time I looked with a bore scope and saw a flaw in the barrel from Manufacturing. Sent the barrel back and they sent me a new replacement. I fitted it myself and it shoot OK but not "Killer" as someone says but the more rounds I've put through it, the better it has shot. I also have a bushing I bought from Dan. I have yet to fit a barrel with the bushing that has shot as well as the barrel I have now. It may make a pretty good case for the large tenon or maybe just happenstance but Id agree with Jerry on the size thing at this point.

Pete

Pete,

Thanks for your input. I agree with Jerry too.

I don't think there is even a question the best way to go is with the .750 tenon vs the 1.062.

Although there are work arounds, and exceptions, why make this any harder than it has to be.

TKH

[Slick Willy]

Who says we don't get crapped on? BTW, most people really don't need to be doing it. Until you have done a good number of them with a correct procedure, most likely you will just eff it up anyways. I probably did 50 or more until I felt really comfortable doing them and not questioning my job.

I forgot that you have a shingle ,My Bad ! But you are not going old school on us ! And it took you about 8 years to get the Rim Fire engine fully up to speed ! Congratulations ,you did it ! You were a student and a Engineer and went to the source to get it from those that knew ! And damn you can do it ! Impressive to say the least ! Not all engineers could or would do that to make their products with a prioritized Shilen or Muller ! Kind of Humorous watching some this stuff ,ain`t it ?

[tim]

Any idea if either of the two guns Ivan has prototyped for MB use a large tenon or a bushing ? This weekend's shoot should prove interesting.

[tim]

In the not too distant past anyone but a barrel maker who lapped and admitted it was chastised and called an idiot for doing it, how dare anyone even touch the inside of their barrel. Its good to see others doing it, talking about it and not be crapped on for mentioning it.

Pete

No Pete that is simply not true...... yet another Wassism.
Jerry, I'm pretty sure, learned how to properly lap a barrel with a lead lap and compound as opposed to you who did, God knows what with felt pellets and some compound.
That is called polishing, which is why your barrel no longer would distribute lube, which is why you had leading( probably) back when you droned on endlessly about rimfire leading.

[Pete Wass]

No Pete that is simply not true...... yet another Wassism.
Jerry, I'm pretty sure, learned how to properly lap a barrel with a lead lap and compound as opposed to you who did, God knows what with felt pellets and some compound.
That is called polishing, which is why your barrel no longer would distribute lube, which is why you had leading( probably) back when you droned on endlessly about rimfire leading.

It works. we have made a number of good ones out of duds. I never wanted to go to all the trouble of casting laps. What you don't know, you don't know very well. You keep proving it time and again.

Pete

[DEFTI RIMFIRE]

Very nice post Tony, it’s great to see the movement away from the “support” theory of one vs the other (the train wreck that occurred in my thread on AS) and into more applicable info. I happen to like the smaller tenon where I might take advantage of how it’s best used, but as I’ve said, there are reasons I’m using the larger tenon. I’ve also stated openly, if I were to design the action differently for things outside my current reasoning, I would likely use a smaller tenon, so there’s no basis for challenging anything you’re saying here.

Thank you for posting good info,
MB

[MilGunsmith]

Has anyone tried making the bushing as part of the barrel chambering process? Turn and thread tenon for a close fit to a internal threaded bushing blank. Screw blank on to tenon, using 620 Loctite. After Loctite cures, indicate bore to confirm alignment, and then turn down and thread bushing to fit action. Finally chamber. This is the method I use for EPVAT pressure barrels at work, as we get all different sized barrels to test.

[tonykharper]

Has anyone tried making the bushing as part of the barrel chambering process? Turn and thread tenon for a close fit to a internal threaded bushing blank. Screw blank on to tenon, using 620 Loctite. After Loctite cures, indicate bore to confirm alignment, and then turn down and thread bushing to fit action. Finally chamber. This is the method I use for EPVAT pressure barrels at work, as we get all different sized barrels to test.

MilGunsmith,

Yes there have been bushings made to fit straight profile barrels to large tenon holes. I'm sure some were better than others.

I believe the best way to make the bushing is to thread the outside of the bushing to fit the action barrel threads, and shoulder it. Loctite bushing.

Set the action up on a tight fitting mandrel through the action bolt raceway, face off the bushing square to the bolt face.

Indicate your center, drill and thread the inside threads for the barrel through the bushing. Then thread and chamber barrel.

There may be better ways. With all this said I don't think I want anything to do with barrel bushings.

Thank you for your input.

TKH

[tim]

Has anyone tried making the bushing as part of the barrel chambering process? Turn and thread tenon for a close fit to a internal threaded bushing blank. Screw blank on to tenon, using 620 Loctite. After Loctite cures, indicate bore to confirm alignment, and then turn down and thread bushing to fit action. Finally chamber. This is the method I use for EPVAT pressure barrels at work, as we get all different sized barrels to test.

FWIW when we had several done around here on 40X’s and Swindlehurst’s a while back, the previous mentioned smith felt that by inserting the threaded bushing in the action and THEN indicating and inside threading, you corrected any action misalignment (usually the case with 40 X’s) and now had a nicely aligned barrel.

[Jerry Halcomb]

to the big tenon. There are those that believe the part of the barrel that meets the face needs to be larger than 0.900. (I am not necessarily one of them btw). There are good smiths in this sport that like the old #7 contour Shilens and R0 or Ross tapers also. IF that is the case and IF the barrel maker or person lapping the barrel laps it correctly with a taper, the situation changes. In my mind the big plus of the smaller barrels is our knowledge of tuning them. The R0 or Ross retains that. IF we now have that correctly lapped barrel we need to install it. When the tenon is cut, the barrel expands (if a button) and that may or may not be a disaster. Cutting a 1.200 diameter to 0.750 causes more distortion than going to 1.0625. In that case, the finished barrel on the large tenon will more closely resemble the initial shape. It also gives more surface area at a larger radius on the action face, in either case which gives better structural support. In the large tenon case, the torque in which you tighten the barrel to matters MUCH less.

All that being said, IF THE R0 OR ROSS TAPER BARREL IS LAPPED SUCH THAT IT LOOKS LIKE A PERFECTLY LAPPED 0.900 BLANK, (that's not impossible btw) I might go for the big tenon action over the small for:
1. more face contact and
2. less tightening torque distortion.

In the end, if I am going to build actions for the masses, I will build a 0.750 tenon IF the action design allows for it. (tough on center lockup). I may also build myself a large tenon and experiment though. The big kicker there is that I have the ability to lap my own barrels. Truth be told, on anything other than a straight 0.900, I rough cut the tenon before I lap it anyways for reasons listed above.

Jerry
Do you start with Shilen blanks that are as buttoned, not lapped by Shilen?
Do you use the rear entry wrench As Killough sells to torque your barrels?
Your dedication to buy and Lap 50 barrels to learn is admirable. That takes some time and money.
Thanks for your information.
Jerry Halcomb

[stiller]

Jerry
Do you start with Shilen blanks that are as buttoned, not lapped by Shilen?
Do you use the rear entry wrench As Killough sells to torque your barrels?
Your dedication to buy and Lap 50 barrels to learn is admirable. That takes some time and money.
Thanks for your information.
Jerry Halcomb

No, I start with them already straight lapped just as they send them out. They will not sell an unlapped blank according to Wade some time back. I would still get them straight lapped. They do a great job of getting that done. I only add a few tenths of taper to them. It's a pretty quick process after they have done the bulk of the work. This is only done on the Octagons. Their ratchets are already taper lapped.
Yes, I actually build them for KSS
Thanks.

[BillBrawand]

very clear tony.
We were lucky up here, we had a real master at them.
You are spot on, from what i know, most guys make a bushing with internal threads and screw'em on....crooked most times.
Tommy fargnoli, the guy that made those lovely 40x sporters by making repeaters out of them, complete with 6 o'clock pins, said you had to thread them while they were into the action and trued up to yield a nice aligned barrel.
Thanks again tony.

there was a fellow who skined a 4-0x stock to make weight instaled win 52 b with d triger made 2oz kenyon with 18 in. Hart straight and broke all records in sporter class at the shamrock range tht nbrsa rimfire natls. Bback few yrs ago.

[BillBrawand]

[QUOTE I IGHT MENTION I CHAMBERED 22 CENTER FIRE BARREL FOR RIMFIRE ONE OF THE MOST ACC. I HAVE EVER SEEN WITH FIOCCHI I TOLD THIS TO BILL MEYERS HE DID SAME LATER AND GOT SAME RESULTS WI9TH ELEY I ALSO HAVE A NEW SPORTER BILL BY BILL WITH MAPLE HAVT SHOT IT YET IN MATCH BILL Bstiller;837244]to the big tenon. There are those that believe the part of the barrel that meets the face needs to be larger than 0.900. (I am not necessarily one of them btw). There are good smiths in this sport that like the old #7 contour Shilens and R0 or Ross tapers also. IF that is the case and IF the barrel maker or person lapping the barrel laps it correctly with a taper, the situation changes. In my mind the big plus of the smaller barrels is our knowledge of tuning them. The R0 or Ross retains that. IF we now have that correctly lapped barrel we need to install it. When the tenon is cut, the barrel expands (if a button) and that may or may not be a disaster. Cutting a 1.200 diameter to 0.750 causes more distortion than going to 1.0625. In that case, the finished barrel on the large tenon will more closely resemble the initial shape. It also gives more surface area at a larger radius on the action face, in either case which gives better structural support. In the large tenon case, the torque in which you tighten the barrel to matters MUCH less.

All that being said, IF THE R0 OR ROSS TAPER BARREL IS LAPPED SUCH THAT IT LOOKS LIKE A PERFECTLY LAPPED 0.900 BLANK, (that's not impossible btw) I might go for the big tenon action over the small for:
1. more face contact and
2. less tightening torque distortion.

In the end, if I am going to build actions for the masses, I will build a 0.750 tenon IF the action design allows for it. (tough on center lockup). I may also build myself a large tenon and experiment though. The big kicker there is that I have the ability to lap my own barrels. Truth be told, on anything other than a straight 0.900, I rough cut the tenon before I lap it anyways for reasons listed above.[/QUOTE]