Kodiak barrel fit trouble

[joshb]

My .02: DON'T BUY ANY MORE USED BARRELS!!!! Too much of a crap shoot and false economy.

But it looked good on the lot and the guy said it was only driven to church on Sundays by a little, old Lady!

I knew there were perils in buying a used barrel. I think I've read half of all the posts on this site, since before I joined. It's been mentioned quite a few times. It was only $200 and I figured it was worth the risk. I want to try the 30br to see if I like it. Some guys have mentioned that they don't like the recoil, but getting a definitive answer is like finding cavities on hens teeth (quoting Dusty). Ya don't really know till you try it, so I thought this would be a good way to "dip a toe".
So:
Modify the action? No. What HPshooter said.
Get a pro to fix it? Yes. Besides, I can't find my good file.
I would like one question answered. How did this barrel fit a Panda? All I've heard about Kelbly's work is stellar, so I think the action's threads would match. Josh.

 

[hogpatrol]

But it looked good on the lot and the guy said it was only driven to church on Sundays by a little, old Lady!

So:
Modify the action? No. What HPshooter said.
Get a pro to fix it? Yes. Besides, I can't find my good file.
I would like one question answered. How did this barrel fit a Panda? All I've heard about Kelbly's work is stellar, so I think the action's threads would match. Josh.

Like a learned poster said, stacked tolerances. A half a thousandth too big and a half too small isn't going to wear away. On another note, I don't care who says what about which action, or how many times they screwed and unscrewed a barrel on XYZ action, headspace will have to be checked and possibly corrected. To do so otherwise is foolhardy and dangerous.
Edit: Did the Panda installation have a recoil lug? How long are the tenons on both? Are they the same? Will the bolt close when the barrel is in as far as you can get it?

 

[Riesel]

Like a learned poster said, stacked tolerances. A half a thousandth too big and a half too small isn't going to wear away. On another note, I don't care who says what about which action, or how many times they screwed and unscrewed a barrel on XYZ action, headspace will have to be checked and possibly corrected. To do so otherwise is foolhardy and dangerous.
Edit: Did the Panda installation have a recoil lug? How long are the tenons on both? Are they the same? Will the bolt close when the barrel is in as far as you can get it?

Josh, these are treacherous waters you are wading in. Too many unknowns on the used barrel. Seek the help of a professional. A machinist should be able to figure out the problem. Leave the action alone or the original barrel won't fit properly.

 

[kendog]

When I cut a barrel from a blank, the difference between not threading on, and a nice tighter than class 3 fit is sometimes less than .001" in feed on the compound, which is set at 29 degrees. Just how much metal is being removed with this last pass that produces the tin foil chips? How much metal is being removed with light lapping of a shank that almost falls on? How much metal is going to be removed when chasing the threads? I understand we dont want to wallow out the receiver, but I think this is being "overthunk". I build switch-barrel guns all the time for guys that shoot both F class and "Tactical" matches, and also multiple barrel fits for same chamber so the guy has a fresh barrel on hand when traveling to shoots. Sometimes there is a very slight, but noticeable (to me) difference in the fits between the two on the same receiver. Guess what? They shoot lights out, and good enough to win a fair share of the matches they enter.
All that being said, the OP bought a used barrel and even if we got it to fit up just perfect, there is no guarantee that something else may not be wrong with it. Given that scenario I would probably recommend not using it. As far as action threads matching, no two receivers are exactly the same, even from the same Mfr.
Just my .02

 

[gunsandgunsmithing]

Yep, this is definitely being "overthunk". There'd be absolutely nothing wrong with chucking the barrel up and using the correct pitch thread file to fit the tight barrel to the action. This ain't complicated. In the "real world", this is a much better option than attempting to chase a half thou or so from the threads. A thread file is made for this exact type of thing and won't hurt a thing. Whereas, barely missing the proper "chase", and you've got a potential mess.

 

[BoydAllen]

I think that yours is the best reply. On the previous post, personally, I do not like very close tenon to action fits. I know that they have been assumed to be evidence of superior workmanship for a long time, but I disagree. I think that fitting them a bit loose is better, and a lot loose if the action threads and face are not perfect.

 

[Dusty Stevens]

Loose threads that wiggle a bit and lock up tight always shoot better. If you lapped it in the fit would be a lot tighter than i like. When one goes on 3/4 of the way one more thousandth on the compound puts it right where i like it for fit

 

[gunsandgunsmithing]

Loose threads that wiggle a bit and lock up tight always shoot better. If you lapped it in the fit would be a lot tighter than i like. When one goes on 3/4 of the way one more thousandth on the compound puts it right where i like it for fit

...but I'm sure you'd agree that once it's taken out of the original setup, and re-chucked and indicated in, chasing that thread that only needs .001 or less removed for good fit, isn't easy to do just right. The finer the thread, the harder it is. Even with a perfect setting to chase the thread, loading the cutter takes out any lash that is in the machine. That also has to be factored for. It's dang near impossible to chase one just a very small amount, to me. Like you said though, I'd much rather have a thread that is too loose vs. too tight. I don't consider a tight fitting thread a mark of good machining as much as a mark of not understanding how a thread works and why you need clearance. Most smiths and other people in this industry thread to fit. There is seldom a need to do anything else. There simply isn't much need for wires and thread mics if you have the parts in hand. I do have wires but prefer a ring gage that I have for common threads that I use.

 

[joshb]

Josh, these are treacherous waters you are wading in. Too many unknowns on the used barrel. Seek the help of a professional.



Thanks for the concern, Riesel. These waters are dark and dangerous. I'm a fairly cautious guy. That's the reason for my post. Another reason is gaining knowledge. I like to understand how things work, especially my things. I really appreciate all the responses.
I did measure the tenon lengths and they are the same. I was screwing the barrel on to check headspace and bolt function. the barrel is supposed to have 500 rounds on it and from what I've read here, that's "lightly used" for a 30br. I bought it from a member here, who has excellent sales feedback and reputation. No guarantees were offered or expected. I kinda figured the barrel and action would go to a Smith to be checked. I've been buying some other barrels and actions and making a "pile" of projects for the smith.
I have to thank the guys that PM'd me, also. I'll be responding to them, shortly. Been a little busy, lately. Josh

 

[JohnMill]

Hey Josh,
If you are going to do this kind of stuff you need a metal working lathe and some knowledge (skill takes years to aquire). The first guy that taught me said (like one of the other posters)the barrel should screw all the way down without tightening up. You then back it up a bit and slam it shut. be sure you grease the threads with.........I use bolt grease or assembly grease. It will take an action wrench and a barrel vise to get it apart. You can chuck it up in a lathe and chase the threads with a thread file. It's got 8 thread pitches, one on each side of the square, 4 on each end. You don't need to be a gunsmith to fit a barrel to an action BUT you do have to know how to fit a barrel to an action