Barrel Fitting Advice Needed

[Mainer]

I recently purchased a .308 Ultra barrel.

When mounted on the frame I want to use, the barrel resists locking up unless the action is closed briskly.

When the action is closed, there is a visible gap between the top rear of the barrel and the top of the receiver (standing breech?).  The bottom half of the barrel appears tight against the standing breech.

I have removed the ejector from the barrel and the problem persists.

I have read the sticky on Barrel Fitting 101.  I assume that I need to remove metal from the pivot point under the barrel.

The idea of removing metal makes me cringe, so before I do so I need to confirm that deepening the hinge point under the barrel is the correct fix for this problem.  No, I do not plan on modifying the receiver.

Also, I understand that the hinge point needs to be deepened (not widened) with a cylindrical object .370" in diameter.  I am planning on using 400 or 600 grit automotive sandpaper as an abrasive.  Any reason not to?  Can anyone recommend a particular diameter drill bit to wrap the sandpaper around?

I apologize for the basic questions but I'd rather ask now than after damaging the barrel.

[trotterlg]

You do need to remove some metal from the hinge area, but that is better than having to add it.  I would not use emery cloth or paper, I have tried this and it is very difficult to make the raidus the right diameter, it is either too large or too small, and either is bad.  What I finally did is take a small plate of about 3/8th aluminum about 3 inches square and bolt the barrel to it using a couunter sunk screw through the base and the large hole in the hinge thing under the barrel that the extractor rides in and has the hinge on one end and the latch shelf on the other.  I then used that plate to hold the barrel flat and parallel on a drill press, and chucked up a .375 diameter steel rod, (.375 is what you need).  I put some valve grinding compound on the rod and the hinge area and just ran the drill press at low speed with the rod through the hole in the press plate and the rod in the hinge  of the barrel, the plate is used to keep the barrel at right angles to the honeing rod.  I just pulled on the barrel to hone out the hinge, It made the best fitting barrel I have.  I probably need pictures, but I hope you can get the idea.  Larry

[Mainer]

Larry:  I understand your description, but I don't have ready access to a drill press.  I may have to find a section of .375" rod and use it by hand (or with a hand held drill) to deepen the hinge point.  I like the idea of using valve grinding compound.  Thanks.

[trotterlg]

I think if you held the drill horizontal and just sort of hung the barrel on the rod you would do fine also.  My first try was with the sand paper, I ended up with an under sized hinge, then honed it up to size with the rod and grinding compound.  It won't take much to fit it.  Also while you are fitting it, you may want to take a flat stone and take the machine marks off the rear of the barrel where it contacts the4 standing breach, they are normally fairly corse, and you can make it very flat and smothe and the fit will be even better when you are done.  Do this before you hone out the hinge.  Larry

[Mac11700]

You may want to smoke the latch shelf before you start taking any metal out of the hinge pin area...you need a 1/8"-3/16" line all the way accross the shelf on lock up.....if this is holding the barrel from locking up...use a white Arkansas stone and stone the shelf evenly...this is a stone a-little...try and fit it by smoking the latch again...you may find this allows a complete lock up with out having to remove any metal on the hinge...I've had 2 barrels like this...had about a .008" gap at the top...stoned the latch ...fits extreamly tight...down to .0015" now..

From the Barrel Fitting 101...by Quickdtoo..

You want the emery cloth wrapped drill bit to measure as close to .370" diameter so the pivot surface is the same size as the pivot pin...so use the right size drill bit to get that total diameter including the emery cloth

The main thing to remember...is to go slow...one or 2 strokes...maintaining even pressure with the emory clothed drill bit...and keeping the drill bit perpendicular to the lug...holding it in your hands..can result in a uneven hing area..(been there...done that...)..so..clamp it down so you only have to hold the drill bit...it's a-lot easier doing it this way...and makes getting a even lug soooooo much easier...

Mac


It's not as difficult as you think...fight the impulse to just start filing metal away...don't rush it...one or 2 stokes with the stone or emory clothed drill bit...and try it again...you can always take off a-little more...if needed...but remember this...you can added a layer back with the feeler gauge strip...and stone it down if you take off too much...

[Mainer]

Larry:  I like the idea of starting off by stoning the back of the barrel flat.

Mac:  After reading your post, I don't know whether to start by working on the lock up shelf or the hinge point.  Most of the time the barrel doesn't lock up at all.  I really need to close the action firmly (more firmly than I think is good) to get it to lock up.  I think the lower rear of the barrel is hitting the standing breech prematurely.  Originally I had intended to do the hinge point first and then fine tune the shelf.  What do you think?

[dodd3]

mainer before you do anything check the under barrel lug where it is welded to the barrel and make sure there are no lumps of weld,this will stop the action from closing up properly my buff classic had this.barrel tight at the bottom and gap at top when i removed the weld dags the action fully closed with no gap between barrel and standing breech and the firing pin strikes in the centre of the primer now.any new action needs to bed its self in .hope this is some help.
bernie :-D

[trotterlg]

If there is a gap at the top it is not a latch shelf problem.  Avoid work on the latch shelf until all other options have failed.  Larry

[quickdtoo]

Mainer, if the barrel face is hitting the standing breech at the bottom only and there's a gap at the top after you've cleaned up the barrel face, it means there's too much metal between the pivot and the barrel face, the only way to make a fit there is to deepen the pivot just enough for the barrel to fit flush against the standing breech with no gap. I'd make sure there's nothing on the bottom of the barrel or in the frame to prevent it from closing properly. After that is done, smoke the latch shelf and hone if needed until you have good engagement. As always, go slow and check often, you can always removed a little more metal, but it's a lot harder to put any back on!!! :wink:

[Mac11700]

Larry:  I like the idea of starting off by stoning the back of the barrel flat.

Mac:  After reading your post, I don't know whether to start by working on the lock up shelf or the hinge point.  Most of the time the barrel doesn't lock up at all.  I really need to close the action firmly (more firmly than I think is good) to get it to lock up.  I think the lower rear of the barrel is hitting the standing breech prematurely.  Originally I had intended to do the hinge point first and then fine tune the shelf.  What do you think?

That's a little different then what I thought you meant at first..I thought you meant if you slammed it closed..it would lock up but if you closed it..you would get a bit of a gap....sorry...before removing any metal in the hinge area...check for anything outside the hinge pivot..that can cause the barrel to hold out on the top like Dodd3 said....this isn't just a 1 step process..if there are no obstructions and the barrel is hitting low..check for burrs on the lower section of the chamber where the 2 surfaces will meet..look at the latch shelf closely..Is it smooth all the way accross?...It needs to be to ensure a good strong lock up...I had 2 barrels that had raised areas on them out towards the corners...and the barrel wouldn't lock up unless slammed shut...I removed the illregularities..and now it locks up tight as a drum..The tighter everything fits...the more accurate it will be..

If you do have to remove metal in the hinge area...like I said before..go slow..the way Quickdtoo has given works pretty darn good...but securing the barrel as trotterlg has said would work real good too if you have access to a drill press..if you don't...secure the barrel in a padded vise at least...

It's sooo much easier saying what's wrong when you can actually see what it's doing...Sorry for the confusion..

Mac

[quickdtoo]

As for the method of deepening the barrel pivot, use what ever works for ya, I've used a single wrap of crockus cloth on a drill bit on several barrels and it works fine, a file of the right size would work better, but I don't have one that size. They all shoot sub moa, so I can't see changing what works for me.  Whatever you use, it's imperative to keep the surface square and not off center or rounded. :wink:

[Mainer]

I've discovered that the shaft of a 9/16" bolt is exactly .370".

I only need to remove a small amount of metal from the hinge point.

Do you think it would work if I put valve grinding compound on a 9/16" bolt and turned it by hand in the hinge point?  (It's too big to turn in a power drill).  Alternatively, I could put valve grinding compound on the bolt and work it back and forth in the hinge point.

Let me know what you think.  Thanks.

[quickdtoo]

Sounds like a plan, let us know how it works out.  :wink: I may have ta try that myself on the next one that doesn't need much "adjustment"! Just to be sure, measure the hinge pin to verify its diameter, all of those I've worked on have been .370", but there may be more than one size since Larry's was .375".

[Mainer]

Fitting the barrel will be my Friday evening entertainment!! :grin:   Maybe I need to get out more!! :-D

[quickdtoo]

I'll be home if ya need some cyber moral support!!

[Mainer]

Between getting the house ready for winter and the Thanksgiving Holiday I got sidetracked from this project.

This morning I started working on it.  As suggested by Larry, the first step I took was to begin stoning the breechface.

Amazingly, after taking just a small amount of metal off the breechface, the action already locks up better.

From the picture, you can see high spots I stoned down.  There's still a small gap between the top rear of the barrel and the top of the standing breech.  The bottom is tight.  I'm going to do some more stoning to see if that gets it to lock up tight.  If not, I'll work on the hinge point.

[Mainer]

I got excellent results from stoning the breech face.  I got a tighter fit of barrel to frame than the factory did with the original barrel.  All I did was stone the breech face.  I didn't touch the pivot notch at all.

It took 2+ hours of stoning and the medium stone worked much better than the fine stone did.

[quickdtoo]

Hmmm, less headspace, hope it still works for ya. :wink:

[Mainer]

True, but the amount of metal I removed was miniscule, so I suspect the headspace will be fine.  In fact, I didn't even remove all of the bluing from the breachface.

[RemingtonMagnum]

Why is it more shinny on the outer circumference of the barrel?. The center of each long black mark is deeper and darker why? Will this cause a Simi circle and a rocking chair effect? Will you be better for creating this affect?

If you stand the barrel on the chamber and a piece of glass with the barrel up in the air can you see between the two? After standing the barrel up get level with the glass and chamber if it is cut Simi Circle you can see about .003 under each side of the barrel (outer circumference) and the glass!


Don Jackson Remington Magnum

[Mainer]

The dark spots on the breechface are bluing that remains after the stoning.  They are low spots from the factory machining processes.  I could stone them out completely, but that would require removing a little more metal.  I've already got a good fit.  The breech face is now substantially flatter than it was when I started.  The factory breechfaces are quite rough.

[RemingtonMagnum]

These dark marks can be made from slack in the auto feed in a milling machine, and bluing. I know because I have created them on a face surfacing. If the barrel is surfaced with the end of the mill tool it will cut cleaner.

Don Jackson Remington Magnum

[Ricci Price]

If your a reloder you can always shorten your fl die to shorten your cases a little, won't hurt a thing, just remember that your pressure may raise a little with reduced capacity. I would check it with a factory case and see, I suspect you'll be fine. I done the samething to another barrel but I removed about .003 and I still didn't have to shorten the die.

[trotterlg]

That is a very nice looking job!  The dark is just low spots, just think how low they were before you worked over the breach.  If it locks up good then I would say you will have a very nice shooting rifle.  You can drop a round in the chamber and measure the depth to the rim with dial calipers with the depth gage, my .223 was .003 on one side and .001 on the other side, that was factory.  Generally on a rimless case up to .006 is consiidered good, and less is better.  I had my .17 rem machined to .0005.  Larry

[MSP Ret]

Mainer, a 3/8" drill bit shaft is what I have used. A 3/8" drill is .375". A 9/16" drill bit is .5625". If you have miked the shaft of a 9/16" bolt and it is .370 go for it. That diameter with some fine paper on it should work great. I have used the shaft of a 3/8" drill bit with fine paper and it worked fine also. Doing it by hand is an easy job, place the barrel lug in a vise being careful not to tighten on any cross pins, you only need to hold the barrel snug enough and vertical so you can file level, flat, and evenly. Good Luck, take you time and check the fit often, stopping just before it's an easy fit, it will wear in the final little bit. Remember it's easier to take a little more metal off later if it does not wear in than having to add some back again....<><.... :grin:

[Fred M]

Mainer.

One thing I do is to smoke the chamber end of the barrel then ease the barrel down to see if the barrel is touching all the way across. I found both my Handis to touch on one side. I stone the high spots before I do anything with the hinge seat.

A one to two thou stoning the high spot will perhaps close your barrel just fine. This happens when the hinge pin is not parallel to the breech face or you have some rough tool marks on the barrel face.

When smoke testing the barrel face remove the ejector and spring and check the ejector without the spring to make sure it is not sticking out past the barrel face.

For barrel face fitting if there is a gap put on a piece od masking tape on the hinge seat. The tape will compress some for fitting. The better the barrel face fits to the standing breech the better the gun will shoot. What you want is a zero gap all the way from one side to the other.

This usually takes less than two thou. If it is more than that then you have an alignment problem in the action well. With shims soldered to the underlug you can correct the alignment before you tighten up the barrel gap.