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looks like gases leaking past shoulder?

 
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  #15  
Old 12-08-2013, 03:36 AM
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Re: looks like gases leaking past shoulder?

Quote:
Originally Posted by SidecarFlip View Post
Keep in mind that all bottleneck cases loacate/headspace on the shoulder datum, even your round shouldered Weatherby caliber.
I am pretty sure that belted magnums headspace off the belt.

I understand the idea of just barely bumping the shoulder to keep the case from growing. I do this with my 338-378. In essence you are getting the round to headspace off the shoulder like a non-belted round.

If he has a FL die set to "cam over" and the die is made to spec, then he is surely headspacing off the belt.

Thoughts?

Rob
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  #16  
Old 12-08-2013, 03:36 PM
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Re: looks like gases leaking past shoulder?

So, I cleaned it up real well, ran 7-8 dry patches thru the barrel, got a clean dry rag up in the chamber and swirled it around to dry up any solvent, then stood it up leaning against the counter all nite, muzzle up. This a.m. I didnt think to look in there, but I'm convinced the chamber was dry and clean. I'm kicking myself now for not triple ckecking, and for not indexing the 9th shot, but that is water under the bridge now. Here is what it looked like after I fired it. LOTS of bolt lift.looks like gases leaking past shoulder?-20131208_131206.jpg

looks like gases leaking past shoulder?-20131208_131245.jpg
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  #17  
Old 12-08-2013, 04:07 PM
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Re: looks like gases leaking past shoulder?

Not sure what you mean by "lots of bolt lift". The only time I have seen my 338-378 dent the shoulder like that is with light loads. Not enough pressure to swell the brass out and create a good seal. That in combo with a wet chamber could cause the hard bolt lift you had.

What load are you shooting?

Rob
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  #18  
Old 12-08-2013, 04:12 PM
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Re: looks like gases leaking past shoulder?

Quote:
Originally Posted by robert6715 View Post
I am pretty sure that belted magnums headspace off the belt.

I understand the idea of just barely bumping the shoulder to keep the case from growing. I do this with my 338-378. In essence you are getting the round to headspace off the shoulder like a non-belted round.

If he has a FL die set to "cam over" and the die is made to spec, then he is surely headspacing off the belt.

Thoughts?

Rob
Thats right

...and they do (but I have none), all mine headspace off the shoulder. Having said that and looking at the latest pictures, I'd say there is a headspace issue but not a shoulder headspace, rather a headspace issue with where the belt locates in the chamber.

I'm not at all sure if you can alter the headspace on a belted magnum by altering the relationship between the closed shellholder position and/or the die base because again, I don't have or load any.

I believe I'd be taking it back to the builder with some hard questions (and a smoked case in hand).

I'm curious about the accuracy and how the pills group.

Theoritically, if the cartridge was headspacing (beltspacing in this case) too far out, that would allow the combustion gases to leak around the case and cause what the pictures show. I would assume that it would also cause inconsistent groupings.

Again, not familiar with any belted magnums, I don't own any and don't reload any and I apologize for leading anyone down the wrong path.
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  #19  
Old 12-08-2013, 05:59 PM
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Location: tucson az
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Re: looks like gases leaking past shoulder?

Quote:
Originally Posted by robert6715 View Post
Not sure what you mean by "lots of bolt lift". The only time I have seen my 338-378 dent the shoulder like that is with light loads. Not enough pressure to swell the brass out and create a good seal. That in combo with a wet chamber could cause the hard bolt lift you had.

What load are you shooting?

Rob
Sorry, I meant really hard to open. The load is:
225gr Speer BTSP
96grs H1000
9 1/2 Remington primer
3.735 OAL
Listed as 2850fps, but its just a guess as to actual, I've no chronograph
yet. Groups? Unknown at this time.
Information is power- if any one has any ideas, I'm open, but to be honest, I'm sort of afraid to shoot it any more till a more knowledgeable shooter/smith actually looks it over. Discretion being the better part of valor, and all. This problem has gotten progressively worse, and I sure don't want it blowing up in my face!
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  #20  
Old 12-08-2013, 07:14 PM
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Re: looks like gases leaking past shoulder?

No matter what, so long as the receiver has cross drilled holes in it (most modern receivers do in bolt action rifles) it won't blow up 'in your face'. Those are there for one reason and that reason is to let the pressure escape if there is an issue.

Having said that, if the fire does come out the sides, chances are the action is ukered anyway.

Myself, I've never experienced 'side fire' and don't want to.
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  #21  
Old 12-08-2013, 07:16 PM
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Join Date: Feb 2012
Location: Afognak Island AK
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Re: looks like gases leaking past shoulder?

Hodgdons start load for h1000 and a 225 is 104 gr. That load is for a partion, but should be close enough for your speer.

Hodgdons max load is 111 gr of h1000.

I understand being leary of shooting it more, but dented shoulders and sooty cases are clasic light load symptoms. not enough pressure to seal the case to the chamber.

Was your chamber cut to saami spec with freebore? If so you are surely underloaded.

Hope this helps Rob
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