Am I being silly?

[Wyatt Smith]

Yes, no case split, no breach opening. Do new cases ever split? I have never heard of this, and surely the tens of millions of rounds fired in military use from ill fitting rifles like AK47's support the integrity of new cases.

I have had a brand new factory cartridge separate on a Lee Enfield 303. New cases can and will happen.

 

[Bob Nelson 35Whelen]

Apologies for the boring technicality of what follows. Skip by all means.
Been doing a bit of research into cartridge brass and it's properties, especially Young's modulus. I think I know know what is happening and why. See the curves below (courtesy Physics Stack Exchange, not for brass, but illustrates the point). When you fire the forces are so great that the brass will go instantaneously through it's elastic limit and passes straight into plastic deformation, that is the curved top bit. That is why you can fire-form cartridges. If it is on the rising part its ok, if it passes over then its all downhill from there until the break point at the end of the curve. Note you have far less latitude once the material has been work hardened, see the second steeper curve. Even though the extension begins later it ends earlier and the curve part falls off the cliff sooner and more dramatically. In a nutshell, reloaded brass needs to be quite closely contained in a tight space or you will eventually push it over the edge of the cliff. The greater the head space, the sooner this may happen, even after one reload in my case.
So what is the solution?
1. Bring the head space back into tolerance if you can.
2. If this is impossible use only new brass so you are always on the pre-worked curve. Then discard the brass.
3. There is the option theoretically to anneal the fired brass to restore it's ductility and get back to something like the first curve before reloading. However this is dicey with a headspace issue because plastic deformation will certainly have occured in the first firing anyway and all of the next deformation event will happen at the thinned point created first time around. Young's modulus is about extension per unit length, and if the thinned band is all of say a millimeter or so, then the same few thou of movement due to head space will be happening at that 1mm - result being a split case.

One more thing I have come to realise is that forward pivoted doubles will have some flex, and of course the top barrel in an O/U sees more of it just taking the geometry into account. Now add the extra mechanical advantage of the top barrel firing event trying to swivel about the pin and you see it exacerbates the problem. Cure? A Greener bolt or some other form of top lock up, rising bite, doll's head, etc. Only use modest calibres in O/U especially small framed ones obviously, and never load a hot charge.
View attachment 383480

@Kevin Peacocke
Another option is reload to the fire formed cartridge not original specks. Use a collet die and only size the neck.
Set the O/U up so the bottom barrel always fires first. Helps minimize rotational torque on the frame. A greener style cross bolt only works on a SXS because it uses the space between the barrels that is not available in a O/U.
Bob

 

[Dakota Hunter]

I’ve looked at their rifles and they appear to be fine rifles. I will be following this closely to see how the manufacture handles the problems on your rifle. I sincerely wish they correct your rifle promptly as you deserve.

 

[IvW]

@Kevin Peacocke
Another option is reload to the fire formed cartridge not original specks. Use a collet die and only size the neck.
Set the O/U up so the bottom barrel always fires first. Helps minimize rotational torque on the frame. A greener style cross bolt only works on a SXS because it uses the space between the barrels that is not available in a O/U.
Bob

Not quite true I own a o/u double that has two greener style Kerstin cross bolts, a single cross bolt yes....

 

[Kevin Peacocke]

I have had a brand new factory cartridge separate on a Lee Enfield 303. New cases can and will happen.

Thanks for sharing Wyatt. Has this happened to anyone else?

 

[Professor Mawla]

Thanks for sharing Wyatt. Has this happened to anyone else?

@Kevin Peacocke
During the Bangladesh liberation war in 1971 , I have personally observed shell casings of our service .303 British calibre Lee Enfield rifles separate on more than two dozen occasions . This was 174 grain full metal jacket military ball ammunition . It also sometimes tended to occur in the .303 British calibre Lewis machine guns , which were issued at our LMG ( Light Machine Gun ) posts .

 

[Kevin Peacocke]

@Kevin Peacocke
During the Bangladesh liberation war in 1971 , I have personally observed shell casings of our service .303 British calibre Lee Enfield rifles separate on more than two dozen occasions . This was 174 grain full metal jacket military ball ammunition . It also sometimes tended to occur in the .303 British calibre Lewis machine guns , which were issued at our LMG ( Light Machine Gun ) posts .

Thanks Professor Mwala. Well I suppose that news puts to bed the suggestion that using new cases would solve the problem.

 

[cls]

Good afternoon Sir, just checking to see if you have heard back from VC with a resolution to your problem?

 

[degoins]

"Good afternoon Sir, just checking to see if you have heard back from VC with a resolution to your problem?"

+1

 

[Kevin Peacocke]

Hello CLS and Degoins, no I havent heard anything yet unfortunately.

 

[Kevin Peacocke]

I have had a lot of free time lately, and in the absence of feedback I got out my vernier and my feeler gauge and it seems to me that the problem may have been the action was not closing sufficiently. There were a few high spots on the water table where the barrel horizontal rail contacts it. I measured the resulting gap between the top barrel face and the breach face at about 5 thou. So rather than get out water paper to take off some metal at the high point I just worked the action a couple of hundred times and it seems to have bedded in much better, such that the top gap is now just 2.5 thou with a vigorous snap shut. But the big difference is that the opening lever has now come much further across towards the centre, by about 2mm at it's mid point. I think that has resulted in about 2mm extra sear engagement from what I can gauge, but I cant get in there to measure it. Could it be that all these issues were to do with the breach not closing far enough, thus preventing sufficient locking sear engagement?

 

[IvW]

That will still not solve the rim resses being to deep...

 

[Kevin Peacocke]

True IvW, but we know the rifle fires ok, so I suppose I am looking to assure myself that it wont open even if a case separates. If I am happy of that, then I could fire new cases only. With the 7.5 thou top barrel head space compounded by 5 thou barrel to breach face gap, compounded by the small amount of sear engagement that was obviously enough to both split cases and open the breach. Now we have solved two of those - total head space is now down to 10 thou and sear engagement pretty near maximum. Will it be enough? Is 10 thou acceptable? If only I knew more about all this.

 

[cls]

It's really too bad that @VERNEY-CARRON COLLECTION, a supposedly reputable company has ignored a customer that spent a considerable amount of money on one of their firearms and should be bending over backwards to help them out. You would think that they would be a little more concerned and trying to help out considering there are 63K members here and some of those members potential new customers. After reading all of the posts here I definitely would not buy one of their rifles. Just my 2 cents worth.

 

[shootist~]

.010" Cartridge Head Space (shoulder seatback measurement) seems reasonable (to me) for a DG rifle. I have no idea what factory spec would be. Are you getting these measurements using headspace gauges or fired Vs factory ammo?

 

[NJC]

I’ll preface this by saying that I know they are a sponsor of this site and appreciate the money that they have spent to help provide us this forum, but I couldn’t agree more with @cls statement about not doing business with @VERNEY-CARRON COLLECTION after reading this thread. Which is too bad as I really liked the looks of some of the items in their on line catalog and they make some things on my wish list that others don’t.

What really turned me off was when a member posted in their “200 candles” message that someone needed their help with a problem and wasn’t getting a reply. There was no acknowledgement of the issue just a reposting of their sales information over his note so it wouldn’t pop up on the recent threads section. It just seemed so dismissive toward a buyer who has spent hard earned money for toward a dream purchase.

 

[Hogpatrol]

I have had a lot of free time lately, and in the absence of feedback I got out my vernier and my feeler gauge and it seems to me that the problem may have been the action was not closing sufficiently. There were a few high spots on the water table where the barrel horizontal rail contacts it. I measured the resulting gap between the top barrel face and the breach face at about 5 thou. So rather than get out water paper to take off some metal at the high point I just worked the action a couple of hundred times and it seems to have bedded in much better, such that the top gap is now just 2.5 thou with a vigorous snap shut. But the big difference is that the opening lever has now come much further across towards the centre, by about 2mm at it's mid point. I think that has resulted in about 2mm extra sear engagement from what I can gauge, but I cant get in there to measure it. Could it be that all these issues were to do with the breach not closing far enough, thus preventing sufficient locking sear engagement?

Thinking out loud here and maybe just a WAG, but before shooting it the first time, did you dissasemble it enough to give it a good cleaning? My experience with CZ and their half a barrel of gunk preservative in new rimfires taught me to take every new rifle/action apart, flush it out with solvent and re-lubricate it.

 

[Wyatt Smith]

.010 headspace is too much.

 

[Kevin Peacocke]

Hi Wyatt, that is still with Bertrams brass ar about 55 thou rim thickness. Norma is the same, but Nosler is about 59 thou apparently. If I could get it that would bring the head space down to 6 thou, would that be ok?
Kevin

 

[Bob Nelson 35Whelen]

Hi Wyatt, that is still with Bertrams brass ar about 55 thou rim thickness. Norma is the same, but Nosler is about 59 thou apparently. If I could get it that would bring the head space down to 6 thou, would that be ok?
Kevin

@ Kevin Peacocke
3 to 4 thou would be been better.
Bob