new barrel fitting (again)

[rdlange]

Opposite problem this time with different barrel I just got.  Don't have to shim.  The lug is too long to lock up in my only S1 receiver.  FAQs explain deepening in general, but not as detailed as shimming.  Any one got any personal experience tips on how to deepen the pivot area so it will lock up tight with no slop?  Tool hints?  Not excited about power grinding.  Patience... I know.  Thanks.

Be Well...

[bikerbeans]

Tom,

The things to keep in mind are not to change the radius of the pivot, needs to stay @ .375" and also to keep the pivot square to the breech face, that is not cocked.  I  have done this two ways.  One with a fine 3/8" rat tail file and working very slowly. Note:  just cause the package says its a 3/8" file don't necessary make it so.   Couple of light strokes on the pivot, then clean the pivot & check the fit and repeat as needed.  Another way is a steel rod that is undersize and make up the the difference with emory paper to get the 3/8".  Then slow sand by hand.  You can use a dremel but in my case this means you will shortly be fitting a shim.   Just remember it only takes a little bit of metal removal to go from no lockup to too loose.  Go slow and check often, making sure to clean the pivot and pin each time so you get a true check of the fit.

IMHO, I think the folks who keep buying receivers and barrels until they get perfect lockup, or sell barrels that don't lock up, are probably the smart ones.   Me personnally, I like bangin' me head againist the brick wall cause it fells so good when I quit.

BB

[rdlange]

Kinda figured what you said.  Have a 5/16 drill I'll wrap with 220 should give me 3/8.  I like fiddling with stuff too, so no problemo. 

Just found out the slug barrel locks up perfect on my 'spare' SB2 frame - better than the 30-30AI I had on it.  I guess it should work, even though smaller firing pin.  Time for another SB2... and I just lost sleep over getting a 45-70 barrel.  This never ends.

Thanks for the good advise.  Be Well...

[tallyho]

This never ends.

Yep, that says it all! 

[revbc]

If it's a rimmed cartridge, check the brass to barrel face clearance.  If it's over say .002 (most are well over that) you may have enough to flat file the barrel face and get it to lock up.  Put your barrel on and close the breech and hold it to the light and see if there is a gap at the top of the breech to barrel fit.  If so, and you have plenty of brass to barrel face clearance, commence filing (remove the extractor) the barrel face flat.  Go slow and check your fit by smoking the face.  Once you get aluminum foil to lock top and sides you have about .0005 - .001 clearance.  If it's not locking up, you might have to do a little latch shelf work.  Filing very slowly and carefully.
But in the end you will have a superior fit with very little headspace.  This will cure a lot of FTF problems.

[Papa Jack]

I think If I was doing this fitting I would invest in a couple round stones, like Norton Medium India in .375 dia. . These will give you a nice smooth finnish, Rat tail files are ......well, kinda crude. ( No,No, I'm not flaming you here, not at all ...) I understand, your using tools that you have at hand, but stones don't cost too much and do come in handy if your going to be fitting another barrel someday....
 Stones are available in different grits and most good hardware stores or machine tool suppliers.....              "PJ"

PS: Read post below...Measure the stones for Diameter, mine vary from .255 to .395" dia...              PJ

[quickdtoo]

That'a a great idea Jack, but are they actually .375" diameter? 3/8" Files aren't, they're all under size by at least .005"- .015", but a little under size is better than oversize. I bought a dozen 3/8" chainsaw files which are fairly fine cut, they vary in diameter from .360" to .366".

Tim

http://ssunl.com/ToolRoomRndIndia.html

[gcrank1]

Darken the hook, even 'magic marker' will work, to make sure of where you are really removing metal. It helps you to keep it all 'squared up'. I only want to see metal removal at the bottom of the hook radius, not at the outer edges.
The suggestion to check the rim seat depth and minimize the headspace first at the breech is a good one, then do any hook work.I suggest you remove the ejector/extractor before any of this, it can give you a false reading/fit.

[quickdtoo]

The suggestion to check the rim seat depth and minimize the headspace first at the breech is a good one, then do any hook work.I suggest you remove the ejector/extractor before any of this, it can give you a false reading/fit.

Yes it is, that's why it's the first "adjustment" to be made mentioned in the barrel fitting info,  making sure there isn't excess headspace first.

Tim

http://www.gboreloaded.com/forums/index.php/topic,82412.msg504758.html#msg504758

Before removing any metal from the pivot, use a flat mill file to make sure the barrel face at the chamber is flat, you'll see metal being removed on the high spots as bright while the low spots remain blue. A little degreasing and touch up blue will restore the finish after you make sure its nice and flat. DO NOT file the breech face flat if a factory cartridge is perfectly flush with the barrel face, doing so will cause negative headspace and the chamber will need to be reamed a bit by a gunsmith. But if the face of the cartridge is slightly recessed below the barrel face, you should file the barrel face to true it up and reduce the built in headspace caused by the uneven barrel face. Removal of the ejector is necessary to do the filing, an extractor can remain in place, but you'll probably want to remove the extractor as well to clean up after filing.

[gcrank1]

I am glad you put that 'right on out there' Quick; It cant be stressed enough !!

[Papa Jack]

That'a a great idea Jack, but are they actually .375" diameter? 3/8" Files aren't, they're all under size by at least .005"- .015", but a little under size is better than oversize. I bought a dozen 3/8" chainsaw files which are fairly fine cut, they vary in diameter from .360" to .366".

Tim

http://ssunl.com/ToolRoomRndIndia.html

 Yer right again Tim !!       I just measured my India stones with a "very near"....these are NORTON brand, Number MF234 ( Medium India ) , I have three, one is NEW and it measures .285", the others measure .390" and .395" a little oversize I guess... Looks like these stones are all over the place as far as diameter.
I suppose ya might get lucky if ya bought a dozen of em.....        
Next best thing would to find a nice wooden dowel that is undersize and wrap it to size with a little fine grit sand paper....()   PJ

[Spanky]

I don't remember the size off the top of my head but I used one of my center punches wrapped with 400 grip paper to fit a barrel.
Whatever you do... don't use power tools. Like BikerBeans said, it only takes a second to go from too tight to too loose.

Over the past few years though I have taken the advice of some of the "wise old men" of the site and bought a few extra frames. I always seem to be able to find a frame that will work without altering the barrel.



Spanky