Author Topic: barrel fitting question (Read 1136 times)

MAN - GA · « **on:** February 25, 2014, 09:13:02 AM »

I am trying to fit my 357 barrel factory fitted to a SB1 (small FP gun) to an extra SB2 receiver I have. Will close with ease, but won't lock up if I put a .0015 feeler guage as a shim it starts to fit tight but still won't lockup - a .002 and .0025 shim and it won't close all the way. Do you think that the underlug needs to be shortened up to engage? With no shim on underlug the barrel will not fit tight on the receiver to hold the .0015 shim I it just slides in and out with ease but if I close on a .002 feeler guage it has a heavy drag almost too tight.

Please advise expert GBOers

Dinny · « **Reply #1 on:** February 25, 2014, 09:23:17 AM »

I have found that when using feeler gauges you will lose some thickness when you heat them with a small torch. Also, when sanding them for a rough texture some thickness is removed. You can always sand it to fit once it's in place.

Thanks, Dinny

MAN - GA · « **Reply #2 on:** February 25, 2014, 09:25:58 AM »

so your saying put in a shim on the underlug and work it down with sanding - even though it closes the barrel breach is not falling far enough to engage?

MAN - GA · « **Reply #3 on:** February 25, 2014, 09:30:50 AM »

My first time trying this guys

Dinny · « **Reply #4 on:** February 25, 2014, 09:38:16 AM »

I place the shim on the foward end of the lug, on the front pivot point. Heating it to red first takes the plating off the feeler gauge and takes away the spring temper, making it much easier to form to the semi-circle pivot.

Thanks, Dinny

tacklebury · « **Reply #5 on:** February 25, 2014, 09:41:32 AM »

In that scenerio and it will close completely but not engage, that means that the latch shelf on that barrel is slightly higher than will work with your latch. It's a simple fix. I hold the barrel upright where I can see the shelf decently and take a FLAT diamond file and using finger tip pressure only and no rocking move it side to side. I do about 10 rubs, then wipe off any steel flecks and test it on the frame. If it starts to engage you will feel a slight pressure then it will still pop open. You continue doing this until you cannot break the action pushing down your knee lightly. At that point, make sure all the steel flecks are cleaned up, use cold blue to reblue the latch shelf, oil it and take it for a test shot or two. I say to reblue because if you get uneven wear pattern, you might want to slope the shelf opposite the wear marks. If it doesn't pop open when you fire, shoot a few more and if it's still good you are done. If you shoot and it opens on it's own, just repeat the process and make sure there's a little stronger engagement, and test again. The worst barrel I had to fit was my 7mm-08 and it took about 1 hr of slowly removing material until I got a good lock-up.

MAN - GA · « **Reply #6 on:** February 25, 2014, 09:41:52 AM »

Dinny - so your thinking that I need the shim to get it to lock up and the underlug is too short as it stands right now - I guess I got to compensate for the epoxy to hold shim in place? Kind of difficult to read and apply everything from the FAQ's w/out a little talk thru

Thanks for input

MAN - GA · « **Reply #7 on:** February 25, 2014, 09:45:00 AM »

tackelbury this makes sense - I honestly feel better shooting hot max rounds (GBO reamer) off the SB2 than the SB1 - I intend to make this my go to deer gun as it is the only centerfire I have other than a Hornet. Thanks for input

Dinny · « **Reply #8 on:** February 25, 2014, 09:53:27 AM »

Modifying the latch shelf always gets me in trouble. I either make it too low or uneven. Good thing I'm medical and not a machinist. If the barrel fits loosely and closes with noticeable play, then the underlug is too short and needs a shim. The epoxy squeezes out the sides and into middle. No need to compensate for it's thickness.

Thanks, Dinny

revbc · « **Reply #9 on:** February 25, 2014, 10:05:17 AM »

Before I started filing the latch shelf, I would shoot the Max on the SB1 receiver. Had one...........shot hot loads with no problem.

MAN - GA · « **Reply #10 on:** February 25, 2014, 10:11:41 AM »

revbc you make an excellent point - maybe I shouldn't mess with what isn't broke - I know several have shot the MAX on SB1 without issue - heck it used to be factory offered on cast-iron so maybe I should just send off the receiver and have two. I am sure PETEMI would agree with this philosophy from all his posts

THANKS

MAN - GA · « **Reply #11 on:** February 25, 2014, 10:15:31 AM »

Now I am tied up tighter than a ski rope knot - I scored 400 Hornady 180SSP locally and some brass from fellow GBOers so I can burn some powder and see - I guess?

Spanky · « **Reply #12 on:** February 25, 2014, 10:24:54 AM »

You're driving yourself nuts for no reason. Keep it on the SB1 frame and enjoy it. I've shot a lot of Maxi rounds on my factory SB1 frame with no problems at all.

Spanky

MAN - GA · « **Reply #13 on:** February 25, 2014, 10:29:33 AM »

Guess I'll send the SB2 off for a 30-30 barrel and then I can shoot a deer with both and report my findings!!!! Plug against the 30-30vs. 357 post

Spanky · « **Reply #14 on:** February 25, 2014, 10:32:00 AM »

You'll like 'em both.

Spanky

gcrank1 · « **Reply #15 on:** February 25, 2014, 10:56:53 PM »

Something not often stressed in this barrel fitting thing is that as one is getting the barrel breech down far enough or modifying a shelf is that you must be constantly checking the primer strike for close to center as you do it.
This is easily done with a primed empty case.

revbc · « **Reply #16 on:** February 26, 2014, 12:04:36 AM »

I vote for puttin her back together.......................loadin up those 180's with some 1680 and get after it!

petemi · « **Reply #17 on:** February 26, 2014, 12:31:10 AM »

MAN - GA, at the moment, I have four spare frames. I may go for another barrel or two and that would still leave me with two. They don't come in "Handi" just for fitting. A little while ago, my .38-55 started popping open. I slapped it on another frame, end of problem. I had another with way off center firing pin strikes. I just changed frames. It's a heck of a lot easier than filing and whittling, and shimming.

Pete

ousooners1baby · « **Reply #18 on:** February 26, 2014, 02:40:39 AM »

Not really off topic but somewhat, I have two sb2 frames that just about everything fits. Then I have two that are very picky about what will fit on them.