What's going on here-Fitting

[gunther66]

Received  a stubbed barrel recently. The first one for me that would not lock up tight on any SB2 frame. Decided to put it on a frame that was too short rather than shimming it. It had quite a gap at the top and would not latch. removed quit a bit of metal from the barrel pivot-still have some gap at the top,but now the barrel fit is getting quite loose. Anyone  have any experience with this?
I was very careful to keep the barrel pivot concentric and even. Looks like I will be shimming after all?

[quickdtoo]

It doesn't take much to go from not fitting to loose when it gets close, when I use the mill to cut the pivot, I cut .0005" at a time and test the fit, then make another .0005" cut and test again until it locks up tight.  This is assuming the barrel face is square, that can cause problems too if it's too long on the lower section of the barrel, I've had to file a couple there that were hitting the standing breech and keeping it from fitting, but I would think the stubbed barrel would have a very true chamber face.

Tim

[gunther66]

The problem is the barrel still has a gap at the top. The breech face was cut on the lathe and is perfect. That is why I don't understand what is wrong here. Any ideas?

[bikerbeans]

g66,
 
unless the latch shelf is hitting the breech face if you have a gap at the top you still need to remove more metal from the pivot.  I suspect your fit is "loose" because the latch isn't engaging the latch shelf.  Look at your barrel release lever when you close the action and if the barrel isn't down all the way into the receiver the lever will be depressed from the latch shelf pushing againist the latch.  Once you have enough metal removed from the pivot the barrel will rotate down enough to allow the latch to engage the latch shelf and the latch release lever will move up some from the depressed position. Wish I could take pics, my descriptions usually aren't the best.    Like quick says, go really slow.  When I fit a barrel I use the positon of barrel release lever to tell me when I am done.  When the action is closed I know I am done when the lever moves up but still has some "free play" in it.  If you remove too much from the pivot the lever will be all the way up and you can't wiggle it and at this point a few rounds down the tube is all you will need before you will have to shim the pivot.  Like Tim says "don't ask me how I know this".
 
 
BB

[petemi]

Before I continue with this post, I want to state this.  I own a stub, my .32-20, but I have never done a stub, so I'm undoubtedly missing something.  The question that comes to my mind is why wasn't the shotgun barrel fit to a frame before the stub work was done?  I'd guess that you bought the barrel already made without its dedicated frame.

Pete

[quickdtoo]

Keep at it Gunther, you'll get there.  ;)Concerning the latch lever being loose, I fitted the 376 Steyr barrel to my extra frame yesterday after making the underlug improvement, it locks up like a bank vault and has excellent latch engagement almost identical to the pic in the FAQs, but the lever is tight, doesn't wiggle at all, this is the first one I've had that's like that, just as a few others have mentioned that were concerned because their new factory guns were. 

Tim

[gunther66]

BB & quick:
The latch lever is at the top of it's travel, the barrel still has a gap at the top only, and the barrel has side to side movement and looseness. Seems like if I remove any more it will just make the loosness worse. where from here?

[quickdtoo]

Depress the latch release and close the action, if it won't close with no gap, the pivot need to be deepened or the lower barrel face is interfering.

Tim

[bikerbeans]

g66,
 
Close the action slowly and watch the latch lever.  On a good fitted action, You would see the lever go down on its own and then it will go back up when the latch clears the back of the latch shelf and then engages the latch shelf.   IF you still need to remove a fair amount of metal from the pivot the lever will go down when you close the action but not come back up.  IF you need to remove a lot of metal from the Pivot the release lever may not ever move down from the up position.  Question, how wide is the gap at the top of the receiver/breech?  Generally if it is a big enough gap you can see it then you aren't real close to a good lockup.  One other thought, you said this is a stub, does it have a brazed underlug or a welded underlug?
 
BB

[gunther66]

I just tried this barrel on another receiver. Beginning to look like the latch shelf needs to be built up some as it almost fits this one but has lots of play in the barrel both horzionally and vertically. The latch is at the topmost travel on this one also.
BB, this is a welded lug.

[bikerbeans]

g66,
 
Take the stub barrel and another barrel (that fits your receiver) and compare the two shelfs against each other.  Maybe someone tried to fit it by relieving the shelf? 
 
 
BB

[quickdtoo]

H&R makes 3 different latches to accomodate fitting, Numrich sells all three. 

Tim

[gunther66]

Thank s Tim.
I guess changing the latch is my next move. I'll post how that turns out.