looks like gases leaking past shoulder?

[robert6715]

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

 

[greggc1960]

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.

 

[robert6715]

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

 

[SidecarFlip]

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.

 

[greggc1960]

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!

 

[SidecarFlip]

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.

 

[robert6715]

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

 

[greggc1960]

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 l ary 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

Well, dang, nothing ventured, nothing gained, I guess. I got back in my book, Hornady 8th Edition, and the load I built is on the light side of middle of the road. Online Hogdon, like you said, starts at 104, so I guess I'll try again. Seems odd Hornady published this info, but it is Hogdon powder. Reckon they ought to know. I have some other rounds with 94grs of Hybrid 100V, which is still not a hot load. Maybe better results will occur. What load do you use, Rob? As far as I know, smith used a standard reamer, I certainly did not specify any different, and from what I read, he got the reamer really quick. I've asked him about the freebore(same as throat, is that right), but never got an answer, and kept forgetting to ask again, and ultimatly decided I'd figure it out on my own. I do think the chamber is a touch short. My fl die does toggle. I had anticipated backing it f just a touch, and neck dize only till necessary to bump the shoulder

 

[robert6715]

My factory Mark V Accumark shoots the 300 gr Berger into very small groups with 98.5 gr and 100.5 gr H1000. These are right at or above max loads depending on whos data you use. ALWAYS work up to these loads.

As you can see I am shooting 4.5 gr more powder with a 75gr heavier bullet. That alone should tell you that your loads are very light.

I have never loaded anything lighter than the 250's and they were a waste of my time IMO.

Load some 104gr loads and I bet your problem goes away.

I use a 45 cal cotton mop on a pistol rod to soak up solvent from my chamber, it fits tight and works great. A wet chamber will not allow the case to grip the chamber wall, so all force is put on the recoil lugs. Which is why you were having hard bolt lift with a light load. Also could be that the load is so light that the case is not expanding enough to grip the chamber walls at all, because it is surely not expanding enough to seal out the combustion gases.

Another BIG thing to consider with a 378 WBY based case is the primer. Federal desighned the 215 at the request of Roy Weatherby for the 378. All the load data I have seen says to use federal 215's.

I dont know where the Rem 9-1/2 stacks up in comparison to the federal 215.

Hope this all helps, and look forward to your results Rob

 

[greggc1960]

All you folks that chimed in here when I asked for help, wow, I can't thank you enough. Took some different ammo to the range, and, its a different gun! No problems at all. In fact, it groups fairly well, too. Still gotta bed it, and shorten the die length, but you all have made a believer outta me!! Rob, Sidecar Flip, Barnesuser, Hired Gun, everybody, thanks a lot. Till my next malady, then!

 

[robert6715]

So was it the 94gr of hybrid 100V behind a 225 that you shot?

What you have expierenced is the reason why we should always consult more than one reloading manual when starting a load. The damned lawyers got the bullet manufacturers listing there load data on the light side.

Glad you got it figured out.


Rob

 

[robert6715]

Greggc1960 If it was an ammo issue, may I suggest we ask a MOD to move this to the reloading section, where it maybe the most usefull to others.


Rob

 

[greggc1960]

Absolutely. And yes, I shot the 225gr w Hybrid 100V , did the trick nicely. Thanks again, Rob