Case shoulder cave in

U

Universeman

Inactive
Greetings,

i'm a new member to this forum and i had an issue at the range with some handloads today.

my problem is with my .257 wby mag.
i've been working up a load and took three loads, two different powders to the range today. shot three of each at 100 yards one looked promising. i shot two more at 300 yards and started to get high pressure signs. these loads are well under max in the book and the first three showed only a slight mark on the head.
the last one i shot collapsed the shoulder in severely. i had this issues once before but i discovered that i had over charged those rounds by accident.
my question is if anyone has seen this before and knows a cause. could it be something wrong with the gun itself. the cases seem to have quite a bit of soot on them after firing as well.

the loads we as follows.

115gr nosler ballistic tip
67.0 gr imr 7828

115gr nosler ballistic tip
62.0 gr viht N165

115gr nosler ballistic tip
63.0 gr viht N165

this was all brand new never fired weatherby brass

Shoots factory rounds without a problem

Thanks!
 

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What primer are you using?

Nosler's website said a start of 62 gr and max 66 gr with N-165 and a 115 Ballistic tip.They specified a Federal 215 Primer.That matters.It is the big fire light them up primer.

I suspect you need to pressurize,expand,obturate the case more quickly to get a seal.
 
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I agree. Sounds like you are not using a magnum primer. This can lead to over pressure as well as under pressure. I know it sounds strange, but it's true even for the same load.

Pull bullets you have loaded and start over with mag primers. Standing the rifle up to get the powder on the primer might help. You really want a powder that comes close to filling the case for best results.

Good luck
 
Thanks for the replies. i'm using Winchester magnum rifle primers, WLRM.
would those be good enough?
i kinda started to think that maybe it was not sealing quick enough in the chamber too.
previously i had press formed and shot 50 7mm rem brass in this gun. no pressure signs, still some soot though.
is there a powder that might fill the cases more?
 
Here's what QuickLoad thinks for top-end loads:

Cartridge: .257 Weath. Mag
Bullet: .257, 115, Nosler BalTip 25115
Cartridge O.A.L.: 3.170 inch
Barrel Length: 26.0 inch
Matching Maximum Pressure: 60000 psi

Code: 
Powder	        Wt(gr)	(%Case)	V(fps)	Press	Burn%
ADI AR 2218	78.6	105	3,472	60,000	98
Vihtavuori N570	74.7	100	3,437	60,000	98
Hodgdon Retumbo	73.8	104	3,405	60,000	100
Norma MRP 2	70.2	100	3,371	60,000	100
IMR 7828	66.0	96	3,369	60,000	100
Alliant RL-25	68.3	97	3,358	60,000	100
Hodgdon H1000	70.5	101	3,356	60,000	100
Vihtavuori N170	72.5	104	3,280	60,000	96
Accurate 3100	65.4	98	3,242	60,000	100
					
NOTE:  Calibrate on 105% case fill being right at the start of compression

I make the assumption that your IMR7828/66/67.0gr load did OK, while
the N165/62/63.0gr Loads were relatively low pressure (49,000psi)-ish

Were it me, I'd look real hard at using N570 and/or Retumbo.
NOTE: (Starting lower than listed above until calibrated)

See
http://benchrest.com/archive/index.php/t-36961.html
 
as far as grouping wise the 93 gr of N165 was best. i'm not sure what the pressures would have been though, i didn't have a chrono. i plan on getting one in the near future though.
i have some H1000 that i want to try as well.
i bought some federal primers today, prepped a bunch of brass and will build some more loads tomorrow. wont be a range day, its supposed to be really windy here.
i also cleaned the rifle really well with "wipe out" seemed like it took about a fair bit of copper fouling. i wonder if that will help?
thanks
 
so i loaded up some new rounds with federal large rifle magnum match primers. these loads we doing much better. no soot and no pressure signs. until i got near the end of my loads and one sounded funny and the next round wouldnt chamber. i looked in the bore and there was about 5 grains of unburned powder. any ideas what that could be?
thanks!
 
If it was double base (ball) powder and you don't get the pressure high enough you'll get unburned powder in the barrel. It's much more fussy then extruded (single base) powder.
 
Collapsed Shoulder

The Collapsed Shoulder is in an old Speer manual. Light loads & slow powder are the cause. Use a faster burn rate of powder. Pressure is low & neck not expanding to seal. Make sure the bullets have enough neck tension. The expander should be .002" smaller than bullet diameter. This will keep the bullet from moving when the primer fires. What is your COL? The bullets bearing surface should be in full contact with the neck. If seating the bullet long to get close to the lands/rifling there may not be enough shank of the bullet in the case neck.
 
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I do not know if Weatherby still practices it,but in years past part of the Weatherby design was a substantial amount of "freebore",which,IIRC,would be removing the rifling for about the first inch plus of bore.f your Weatherby has freebore,it will be even harder to get the pressure needed to obturate the case.

I agree stepping a little quicker on the powder might be an idea.H-4831 is a bit quicker and may be worth trying.

Likely its not going to work so well to stay down in the starting load range.You may need to push things closer to max,with all due caution.

Please be aware that with a very high capacity case with a very small bore to let the pressure diminish,pressures can jump from moderate to too high rather quickly.Change one thing at a time and sneak up on it,but it may take a near maxload to work well.

While sometimes the mfgr's tech help is a bit guarded,sometimes making a phone call to Nosler or Hogdon or whatever mfgr you are buying components from will help.
 
Under-powered loadings

The Collapsed Shoulder is in an old Speer manual. Light loads & slow powder are the cause. Use a faster burn rate of powder. Pressure is low & neck not expanding to seal.
Click to expand...

This is the correct answer.
 
Thank you very much for the responses. i'm going to try a faster burning powder and try going a little closer to max. changing to the federal primers has helped too.
i was seating fairly long, at 3.250. i'll try seating a little shorter as well
 
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One thing I would do is anneal the neck and shoulder on the brass. It may be work hardened to the point it is preventing a good neck seal during firing. I shoot a few "overbore" cartridges and Retumbo works well for me. I use it in my 25-06 with the same bullet you are using. Sooty necks are not in themselves a problem but they may be an indicator of the low ignition problem. As stated before, quicker powder, hotter primer ... and annealing may solve the problem. Good luck.
 
I'll try annealing, i actually just bought a temp stick and a torch for that purpose. most of the brass i had issues with was brand new weatherby brass though.
 
Collapsed shoulders can also be caused by ...

excess case lube when sizing the brass.

Failure to seal/obturate can be caused by forgetting to clean the lube off the sized brass when the sizing step is finished. IF THE CASE DOESN'T SEAL, IT MAY SLAM BACKWARD, CAUSING FLATTENED PRIMERS AND ejector marks on the case head-resulting in false excess pressure signs.
 
I just thought i would post an update for any that cared.
new loads are working great, no more cave ins and no more soot on the cases even. i am once again able to shoot my favorite rifle without worry!

Thank you to everyone who offered advice
 
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