The Firing Line Forums

Go Back   The Firing Line Forums > The Skunkworks > Handloading, Reloading, and Bullet Casting

Reply
 
Thread Tools Search this Thread
Old August 1, 2009, 05:55 PM   #1
14cm
Senior Member
 
Join Date: February 17, 2009
Posts: 153
case head seperation

i was shooting some proven loads through my freedom arms. 31.5 of h110 behind a 300gr xtp mag. this load mimics the hornady factory load. 1700 fps.
i guess i should have been checking my cases better. i didnt know it had happened. i fired 5 rounds then checked the string. all looked normal. 1690 to 1710. i went to eject cases and got a suprise. i do not think it was over pressure due to the chrono string. i would guess that it was too many heavy loadings in this case.

14cm is offline  
Old August 2, 2009, 08:34 AM   #2
SL1
Senior Member
 
Join Date: November 8, 2007
Posts: 2,001
Just guessing here

but first guess is that you are talking about a 454 Casull? And, you are loading it pretty hot? (I don't have one, so I only know what I read about them.)

IF I am guessing correctly, I think the max pressure on the .454 Casull is high enough to make the cases grip the sides of the cylinders. Most revolver cartridges are below the pressure necesssary to make that happen. SO, the Casull and some of the really high-pressure rounds like the .460 and .500 S&Ws can develop case stretch, just like rifle cartridges that work at similar pressures. Repeated firings with a little case stretch each time can cause case separations.

Since you didn't write that the case body was tightly stuck in the chamber, I am thinking that the load was not too hot. (I didn't bother to look-up data because I really don't even know what your cartridge is.)

Maybe your pistol has some more headspace than necessary, and that is allowing the cases to stretch more than normal. IF it has more headspace that normal, it could be a manufacturing issue (but Freedom Arms makes really good guns, so I doubt that). Or, the frame might have been stetched a little by a lot of hot loads (but Freedom Arms make really strong guns, so that would require some abuse).

Or, maybe the rim of that particular case is too thin, so It had too much headspace. You can measure that with a caliper.

Or, maybe you just shot too many hot loads in that case. If so, then all of its lot with a similar loading history should be getting close to separating, too. You can check whether that is the situation. If it is, you should be able to detect a circumferential groove INSIDE the case on the wall in the same location as that case separated. In a .45 caliber straight-walled case, you can probably just see it, espcecially if you polish the inside of a case. But, even without polishing, you should be able to feel it with a straightened paperclip that has a small 90° bend at its end.

Hopefully, this will give you some ideas so that you can figure-out what your particular problem is.

SL1

Last edited by SL1; August 2, 2009 at 11:04 AM.
SL1 is offline  
Old August 2, 2009, 08:59 AM   #3
14cm
Senior Member
 
Join Date: February 17, 2009
Posts: 153
what a dummy, i cant believe i didnt post the caliber. it is a .454 cas. the remaining case slid out very nicely. i was getting ready to turn a brass punch to tap it out. however i pushed on it with a wooden dowl and it fell right out. I think i am going to scrap all my brass as i shoot them. they probably have 5 loadings each on them. my bigest problem is the fact i have 300+ loaded. the other problem is with the death grip roll crimp i use, the bullets would not pull well.
I think i am going to drop back to my chipmunk/ground mole loads. I am getting tired of getting beat to death. i can push a 300 gr bullet @ 1200 with little recoil loading 13.3 gr of uniqe.
14cm is offline  
Old August 2, 2009, 10:58 AM   #4
14cm
Senior Member
 
Join Date: February 17, 2009
Posts: 153
sl1, i just checked 50 cases with a booger hook. 8 of them were ready to let go. i guess i never thought about case strech with a revolver cartrige.

thanks, john
14cm is offline  
Old August 2, 2009, 04:01 PM   #5
amamnn
Senior Member
 
Join Date: May 13, 2006
Location: WA, the left armpit of the USA
Posts: 1,323
Just for the edification of others who might be shooting similar loads-- would you care to post the number of times you shot those cases with that load?
__________________
"If the enemy is in range, so are you." - Infantry Journal
amamnn is offline  
Old August 2, 2009, 06:49 PM   #6
14cm
Senior Member
 
Join Date: February 17, 2009
Posts: 153
i would say 3 to 4.

factory fire and 2-3 reloads. i am looking at replacing all my brass. i will shoot what i have loaded and crush them.
i have been thinking alot about hunting with my light loads. the good thing, a light load from a 454 is still more powerful than most other heavy loads. i can get 1250 fps with a 300gr xtp with 13gr of unique and it is a powder puff.
14cm is offline  
Old August 2, 2009, 07:21 PM   #7
Ozzieman
Senior Member
 
Join Date: December 14, 2004
Location: Northern Indiana
Posts: 6,117
The only pistol caliber that I load VERY hot is 44 mag for a Contender. These were hunting loads and were slightly above book numbers and did show signs of high pressure.
I would load new once then scrap them. The sides of the case near the same point that yours failed would have a slightly sand blasted look to them instead of smooth brass, these were also H110. I would only shoot them in a Contender and would mark them so that I wouldn’t accidentally shoot them in one of my 29’s. I would agree with others that you have a case weakened from to many reloading or just a bad case.
I would like to see a photo of the primer of the failed case, to me that would tell more than the case itself.
Having never owned a 454 I have no idea how many loads a case is good for but for me, if I was loading near max, their life times would be very short.
But then again, I am a gutless wonder when it comes to safety.
Ozzieman is offline  
Old August 2, 2009, 08:15 PM   #8
Edward429451
Junior member
 
Join Date: November 12, 2000
Location: Colorado Springs, Colorado
Posts: 9,494
I think it's reasonable to assume that you can thank your close tolerance Freedom Arms 83 for supporting the case enough to not give you a face full of gas and brass!

I've just barely started loading for my 454 but on my heavy 44 mag loads i toss the brass after 3 or 4 loadings.
Edward429451 is offline  
Old August 2, 2009, 08:20 PM   #9
Unclenick
Staff
 
Join Date: March 4, 2005
Location: Ohio
Posts: 14,967
A general rule of thumb is that the dividing line occurs with loads that are at around 30,000 psi at the peak. Blow that, you don't see cases hanging on to the chamber hard enough to stretch the head. Above that, they do. It's not a hard line, because pressure curves are so different, but it gives you a sort of ballpark number. It is why QuickLOAD has you use fired case volume for calculating pressure in loads that peak above 30,000 psi, but using the sized case volume for loads below that peak pressure.

Your Unique load is still getting up past the 30,000 psi point by a little. Try about 14.3 grains of Power Pistol. You should get to the same 1200 fps with about 1/6 less pressure and your cases won't grow any more.
__________________
Gunsite Orange Hat Family Member
CMP Certified GSM Master Instructor
NRA Certified Rifle Instructor
NRA Benefactor Member and Golden Eagle
Unclenick is offline  
Old August 2, 2009, 08:49 PM   #10
14cm
Senior Member
 
Join Date: February 17, 2009
Posts: 153
ozzieman, the prime looks good. rounded edges, no upset in the pin crater. I surely thank you all for the good info. i had no idea about the case streching due to wall gripping.

unclenick, using a 300gr xtp what looks like the best bet for a sub 30,000 psi load? is the power pistol a bulky powder like unique?
14cm is offline  
Old August 2, 2009, 09:41 PM   #11
Unclenick
Staff
 
Join Date: March 4, 2005
Location: Ohio
Posts: 14,967
Power pistol is fairly fine grained and is is about 20% more dense than Unique. I picked it based on it being the fasted thing I could find that still gave 1200 fps at around 25,000 psi. You can go with still slower powders that fill the case better, but of course you end up just blowing the extra powder weight out of the barrel. That gives you an extra large fireball and more muzzle blast, if you like that sort of thing, but the downsides are it means larger charge weights, so it costs more to load, and it leaves the gun dirtier. Waste of money, IMHO. If the lack of case filling concerns you, try a polyester pillow stuffing wad to hold the powder over the flashhole. But try grouping without that first to see if there's actually a problem?

The same powder should give you the same performance with the XTP, but the higher start pressure of the jacketed bullet suggests the load be cut to 14 grains of Power Pistol. This assumes you use Hornady's COL of 1.745" for that bullet, which corresponds to crimping at the cannelure with a case trimmed to the average of 1.373" (maximum SAAMI spec less 0.01", which is standard for trimmer settings).
__________________
Gunsite Orange Hat Family Member
CMP Certified GSM Master Instructor
NRA Certified Rifle Instructor
NRA Benefactor Member and Golden Eagle
Unclenick is offline  
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 07:59 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2018 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent: thefiringline.com
Contact Us
Page generated in 0.06964 seconds with 8 queries