Swap out barrel on Ruger No 3

  • Last Post 15 May 2020
Rich/WIS posted this 02 May 2020

Have a Ruger  No 3 in 30/40 AI and am considering replacing the barrel with another barrel off a No 3 in 30/40.  What are the chances it will index and headspace, has anyone tried this before?

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Doughty posted this 02 May 2020


Having switched around several Ruger single shot barrels I would give it fair odds.  Some "adjustment" can be obtained by how tightly the replacement barrel is screwed in.  In my opinion, Ruger factory barrels are screwed in too tightly.   The single shot Rugers that I have re-barreled lately are only little more than hand tight.  I use LocTite on these and have seen no problems.  If by screwing it in as tightly as you can still doesn't give you correct "clocking" you can remove metal from the receiver front / barrel shoulder area.  Sometimes enough clearance can be gained by lapping the front of the receiver ring square.  Sometimes you need to remove some metal from the barrel shoulder.  Also, it is sometimes necessary to remove some metal from the end of the barrel where it contacts the falling block's face.  Sometimes lapping the block's face square will give enough clearance.  If too much is removed from the end of the barrel it can affect the chamber, possibly requiring that the chamber be "freshened" with a reamer.  Sometimes only the rim recess needs deepening.  My experience with factory #3 .30-40 chambers is that they are frequently so oversize that a little shortening only improves them.  The worst condition, in my opinion, is one in which the clocking goes past top dead center, and is just too loose to be cured by a lite tightening and LocTite.  To set back a full thread length is .0625".  Of course you would never set it back a full thread to clock it, but say maybe .050 or so.  In any event, it would still require reaming the chamber and deepening the extractor slot.  Another fix that is not classy but will work, without reaming chamber, is to make a shim washer to go on the barrel between the barrel shoulder and the receiver face.  A very thin washer, something under .010 doesn't work well in my opinion.  If say, you need to gain .005", use a shim .010 to ,015 thick and then relieve the barrel shoulder to get the correct spacing.

My opinion, the .30-40 was the best of the #3 chamberings.  Good luck.

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Ken Campbell Iowa posted this 03 May 2020

. just a note on the chance you need a shim to get the correct headspace ... it is hard to make a thin shim on a hobby lathe without tearing .. so make  a nice thick one ... maybe 0.12 ... then do the math and cut that calculated much off the barrel tenon shoulder ...  

you could get fancy and use a fat brass shim ring ... looks like a gold inlay .... theoretically this could eventually cause some problem from ionic transfer ... but should be good for 20 or 30 years  ...

i fit winchester take-off barrels onto Ruger rifles and do this if the customer wants to go cheap ..

lastly, if it is just the extractor clearance cut out of time ...  ... you can run that clearance almost all the way around the tenon if necessary and it won't hurt anything.  .... but if for a customer, you need to explain this ugly crutch... hah ...


i might mention that my own ruger 3 in 45-70 .... extractor cut from the factory is about 0.002 too shallow from the factory ...  if i ever need another project i will unscrew the barrel and sink it a tad ...   or actually i have always wanted a 40-60 ... 

just some trivia ... ken

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Rich/WIS posted this 10 May 2020

Well I got the barrel off E-bay and it it is like new,  few tiny marks on the outside and looks about new on the inside.  Tried the local gunsmith but he doesn't do Ruger single shots.  Have seen gunsmiths mentioned on various other forums but they seem more into custom work on the No1.  Any recommendations would be appreciated.

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Ken Campbell Iowa posted this 10 May 2020

hi Rich ...  you might consider doing the swap yourself ... if the ebay barrel is a lucky fit, it would be "" simple "" ... heh ...

or to put it another way, if you try it yourself and find it needs some fitting, you won't be any further behind than if you just take it to a gunsmith in the first place.  actually, a little ahead since you will have removed the original barrel.

the only tricky part is getting the original barrel off.  if you don't have any equipment, you might get a local gunsmith to pop it off for you.  they should have the barrel vise to do that.

if you have a heavy bench vise, you can crutch up a 1-time way to remove the barrel .  or buy a big vise from Harbor Fright and wind up with a handy tool. you can also then screw the ebay barrel back on with the same simple set-up.  what helps is that screwing on the new barrel is much easier than removing a 40 year old barrel that was way too tight and might have dried sealant on the threads.

just a thought...  when govco made us all way much safer by not letting us ship a gun through the post office for $7. it took some fun out of our lives.




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TRKakaCatWhisperer posted this 10 May 2020

My experience (sample of 1).  Changed out the .45-70 barrel with a 375 Win barrel.  Vastly different, took a bit of machining to get it to work.  BUT since it was the gunsmith doing it - I got what I wanted with little effort.

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Rich/WIS posted this 11 May 2020

Have been doing some Googling and have a few leads, Best so far is Penrod Precision, but have some other possibilities to check out.  Doing it myself is not an option, don't have the skills needed or proper tools. I can afford to have the work done and that is a much safer option than doing it myself.

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Wheel Weights posted this 11 May 2020

Have you tried screwing it in ?


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Rich/WIS posted this 15 May 2020

WW, original barrel is still on the receiver and don't have the tools to do any of this myself.  Found a gunsmith in Lexington who has done Ruger single shots before and will be dropping it to him next week.  

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Wheel Weights posted this 15 May 2020

All you need is a barrel vice that you can resell with 10% loss and a home made action wrench.


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