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Offline Tentman

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Barrel Stubbing Problems
« on: March 01, 2008, 12:59:03 PM »
Hello Guys

I have been following the Barrel stubbing thread with interest, as my Gunsmith completed a stubbing project for me.  Applogies in advance for the poor quality photos.

However it has not turned out just quite right and I would sure appreciate the input of you guys as to what might have gone wrong.

Firstly the completed barrelset
and the breechface . 

The stub was from a 22.250 barrel that had already been stubbed when I got it, to 22 Hornet, but the barrel used was an old soft .22 RF target barrel I think, and it had not liked the higher pressures, even if it was good to begin with.

My smith fitted a new take-off Tikka 25-06 stainless barrel - this was a very nice tube, as smooth as anything on the inside.  The dimensions of the stubbing project are approximately (I can't be precise because I only have the finished article to measure) barrel diameter 0.787 giving a stub outer wall of 0.162 .

Now have a look at the picture of the cases.

 Firstly (left to right) a loaded round, then the cases in the order of firing, case 1 and 1a 38.0 grains of H4831 behind a Sierra 100gn SPBT projectile, case 2 (extreme right) 38.5 grains H4831.  These were to my mind light loads, I was just starting up, being very conservative and using starting loads designed for SMLE rifles.

As the cases show, something drastic has happened here, it looks to me as if the chamber has "bulged" at the case neck.  The neck of case #2 (the third shot fired) is all rounded and not at all the right shape.

Any thoughts or comments

Cheers - Foster
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Offline trotterlg

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Re: Barrel Stubbing Problems
« Reply #1 on: March 01, 2008, 01:08:21 PM »
I can't find any pictures, and a picture of the breach end of the barrel would be good.  Larry
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Offline Tentman

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Re: Barrel Stubbing Problems
« Reply #2 on: March 01, 2008, 01:25:11 PM »
Pictures now up. sorry again about the quality and delay.

Cheers
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Offline trotterlg

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Re: Barrel Stubbing Problems
« Reply #3 on: March 01, 2008, 01:29:17 PM »
OK, I see pictures now.  You need to know I am not a Gunsmith or an Engineer that does stress calculations, so what I say, take with a garin of salt.  My first thought at seeing the pictures is that the chamber is cut for a 25-06 AI.  I would be somewhat concerned about shooting a large case diameter in a stubbed barrel, plus it is a stainless barrel which is not as forgiving as a regular 4140 barrel.  The 25-06 is also a 65,000psi round.  I would clean the chamber really well, give it a light coat of oil, plug the bore with a patch just in front of the chamber and melt some wax and pour it in and make a cast of the chamber and see what you get. I would think it would be unlikely it would buldge the way you are discribing, but you never know.  Larry
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Offline billy_56081

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Re: Barrel Stubbing Problems
« Reply #4 on: March 01, 2008, 02:15:36 PM »
Maybe it's the poor picture but that case looks like a rimmed cartridge? It is a 25-06 correct?
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Offline krod47nw

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Re: Barrel Stubbing Problems
« Reply #5 on: March 01, 2008, 04:35:42 PM »
The pictures are not very clear, but I tend to agree with Larry. They look like AI, or some sort of improved shoulder chambering. Your post says the gunsmith completed the project, but it seems to me he isn't quite finished.  I'm not a gunsmith, but how could he check his work and not notice the chamber?

Kevin
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Offline krod47nw

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Re: Barrel Stubbing Problems
« Reply #6 on: March 01, 2008, 04:48:57 PM »
After looking again, the neck on the first (unfired) round looks way too long.  Are these factory ammo, or resized brass?
The round doesn't even look like a 25-06.
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Offline trotterlg

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Re: Barrel Stubbing Problems
« Reply #7 on: March 01, 2008, 04:49:42 PM »
If this is a takeofff barrel the gunsmith would have had to run a reamer in deeper to make a barrel for a Handi so that the case head is flush with the breach.  On any of the bolt rifles the case head is left about .120 high for the extractor to grab the groove in the case head, the bolt head covers down to about .010 from the breach end.  If it was an AI type reamer then things will be fine, he just ends up with a 25-06 AI which if it is properly done will shoot the factory ammo just fine.   Larry
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Offline Smokin Joe

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Re: Barrel Stubbing Problems
« Reply #8 on: March 01, 2008, 05:24:55 PM »
Tentman, that is Not a .25-06 in the picture.
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Offline Tentman

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Re: Barrel Stubbing Problems
« Reply #9 on: March 01, 2008, 05:34:34 PM »
No - not a 25-06, its a wildcat that was common here many moons ago - the 303-25 (a 303 brit necked down to .257) so yes it is rimmed, and yes, we have checked that the chambering reamer matches the dies I have.  Its a mild cartridge that suits SMLE actions.

Look at how the case shape changes from rounds 1  to 2 in the neck/shoulder area.
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Offline trotterlg

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Re: Barrel Stubbing Problems
« Reply #10 on: March 01, 2008, 05:50:58 PM »
I would say it is nearly impossiable for the chamber to bulge at the sholder.  It would really be worth the effort to make a wax cast of the chamber, you will be able to see a lot from that.  I am not sure that a .303 will clean up a 25-06 chamber unless it is cut fairly far back.  The rim makes sense it will hold the cartridge in position, so if the chamber is long (or improved) it will blow the sholder forward just like what you are getting.  Lots of wildcats have to have the brass fireformed to get a proper sholder on it, so you may be seeing an intermediate step in your brass making process.  Then on the other hand it may be ready to turn to tiny little pieces the next time you shoot it.  Larry
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Offline MSP Ret

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Re: Barrel Stubbing Problems
« Reply #11 on: March 02, 2008, 03:06:07 AM »
Just a question, but what does the gunsmith say about this? Has he seen the cases? How familiar are you with the .303-25(?) and have you shot one before and fireformed brass for one before? Do you know anyone that has that you can check with personally? Perhaps the gunsmith? This may all be as is supposed to be. I suggest you start by going back to the gunsmith with everything you have. He is the one who is going to have to decide what is wrong and to make it right. After reading all this I get the nagging suspicion all is not as bad as you may believe. The .303-25 sounds like an interesting caliber....<><....:)
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Offline billy_56081

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Re: Barrel Stubbing Problems
« Reply #12 on: March 02, 2008, 04:38:59 AM »
You might want to Anneal your brass also if this hasn't been done allready.
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Offline Smokin Joe

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Re: Barrel Stubbing Problems
« Reply #13 on: March 02, 2008, 04:45:57 AM »
I'm wondering if the 'smith was shooting for this (25-.303 Improved):

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Offline trotterlg

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Re: Barrel Stubbing Problems
« Reply #14 on: March 02, 2008, 06:39:54 AM »
My guess is that smokinjoe has the answer for you.  Cast the chamber and see if he is right.  Larry
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Offline stimpylu32

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Re: Barrel Stubbing Problems
« Reply #15 on: March 02, 2008, 07:09:41 AM »
Tentman

You have a PM coming .

stimpy
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Offline oneshotonekill

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Re: Barrel Stubbing Problems
« Reply #16 on: March 02, 2008, 03:49:01 PM »
I think what you may be seeing is various but incomplete stages of fireforming.  Using a light load you may not be generating enough pressure for the case to fully form in one firing leaving you with cases somewhere in between.  It looks like the shoulder has to move forward quite a bit from the unfired round compared to the fired rounds and even more so compared to the photo smokinjoe posted (if that is in fact what your gun is chambered to).  I would definately cast the chamber and have a talk with the gunsmith before shooting any more.  Are you indexing the brass?  Just curious what the marks are near the case heads in your pic. 
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Offline Tentman

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Re: Barrel Stubbing Problems
« Reply #17 on: March 02, 2008, 04:13:35 PM »
Hello guys

Panicking early and springing into print is not always the best solution (and an easy way to look like stupid).

On further analysis (aided by a PM from Stimpylu32, and also Oneshot kills coment) and a discussion with the gunsmith here is what we think has happened.

If you have a look at the cases again, the second from left (first one fired) has the shoulder filled out and moved forward.  The third and fourth cases (fired next) have only semi formed shoulders, just why is a bit of an unknown, especially as the powder charge was increased for the last one.

So what does this mean (to me, comments welcome) – well the 303-25 is a very “unstandard” wildcat, and my dies have a longer neck than the chamber reamer, (which has a short neck and pushed out shoulder).  I'll have to adjust the dies for subsequent sizings.  The case necks however are very soft already (can be dinted with a thumbnail), so should push out nicely with a bit more pressure

These cases also have very old primers (1943) which may not be lighting up H4831 very consistently.  I think I will replace the primers and move to a slightly faster powder.

Thanks for your ideas and comments - I’ll report back later .. . .
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Offline wtroger

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Re: Barrel Stubbing Problems
« Reply #18 on: March 03, 2008, 03:03:46 AM »
If the Primers are 1943 then make sure you clean the barrel throughly with hot soapy water. Even though you have only shot this 3 or 4 times I suspect those primers are corosive.
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Offline Tennessee.Traveler

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Re: Barrel Stubbing Problems
« Reply #19 on: March 03, 2008, 10:23:52 AM »
Tentman,

I've fireformed hundreds of .358 Win cases out of .308 brass.  I used 150 gr with 10% under max loads and never had an incident.  What I would love to do is use 45-70 stub and buy a Midway Mauser barrel in .35 Whelen or even .358 win.  I think McLernon knows something about calculating max case use on stubs. 

Dick 
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Offline McLernon

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Re: Barrel Stubbing Problems
« Reply #20 on: March 04, 2008, 05:39:56 AM »
If the stub is shrunk fit there would be no effect on case life. If you have 0.01 inches clearance and fill with one of these super adhesives with steel powder in the gap I have to believe that case life would not be affected. One proviso is that you don;'t get the action too hot too often as the adhesives will break down at prolonged hi temperatures

------but since a Handi is not a machine gun I doubt that this would become a problem. Having said this why not shrink fit the thing. On the down side of shrink fitting,  you'll find it awful hard to get apart if ever you decide to and you have to work to closer tolerances.

JMO

Mc
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Offline Tentman

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Re: Barrel Stubbing Problems
« Reply #21 on: March 04, 2008, 12:31:11 PM »
Hi Mc

Thanks for your comments.  My 'smith must have been on to this cause he mentioned that he had filled the threads with a special grade of Loctite "to reduce the chances of any chamber buldging".

Cheers - Foster

PS Rifle is still shooting ok with slightly hotter loads, will start to test the grouping as soon as I can get to the range.
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Offline McLernon

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Re: Barrel Stubbing Problems
« Reply #22 on: March 04, 2008, 01:52:23 PM »
One thing that has become apparent to me with all the different stubbing projects we have seen in the last year or so is that there is more than one way of doing it :D

Mc ;D
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