Sensible question about stretched cases in a 305.

Lost...again

Lost...again

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Hi.
I have a question and if it is self explanatory, then Im missing it.
Today was range day, and I shot thru two boxes of Remington 150 Corelokt, to get the fresh brass for future reloading
So last night as an experiment I measured the case length on all 40 rounds, 2.010 for all of them.
Tonight I have just finished measuring all the fired cases and Im a bit surprised. I would have expected all the cases to have stretched somewhat but some have shrunk !!
I have case lengths from 2.004 all the way thru to 2.027 and every stop in between.
I shot all the rounds with the gas turned off and a 10 to 15 second pause before ejecting the case.
There were no problems at all with the ammo, just wondering how some have shrunk and is my #### safe.

Cheers.
 
Well that is kinda odd bc the gas was off you would think they would come out more matched in sise ... Are some of the primers giving you a false reading ... It is normal for them to shrink but a 20tho difference is fishey , I think the powder charge was not equal in all rounds how was the accuracy ?
 
I personnaly found out that all commercial load like winchester x or rem lock are on the hot side. Check your primer Im pretty sure its flatted. Thats a bit of overpressure sign. With the PRVI ammo, the case and primer are perfectly fine, maybe theres less powder. I guess the m14 likes no more than 40 gr of powder.
 
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dieseldawg said:
how are you shutting your gas system off?
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With the gas selector. In case you don't know , there is a selector screw in front of the handgaurd on the right hand side . That's only in case you didn't know...not trying to be sarcastic.
I get better results with the gas off, and more fun with the gas on :)
 
Lost...again said:
With the gas selector. In case you don't know , there is a selector screw in front of the handgaurd on the right hand side . That's only in case you didn't know...not trying to be sarcastic.
I get better results with the gas off, and more fun with the gas on :)
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HAHA i wondered what that screw was for!! haha thanks man!
 
Lost...again said:
Hi.

Today was range day, and I shot thru two boxes of Remington 150 Corelokt, to get the fresh brass for future reloading
So last night as an experiment I measured the case length on all 40 rounds, 2.010 for all of them.
Tonight I have just finished measuring all the fired cases and Im a bit surprised. I would have expected all the cases to have stretched somewhat but some have shrunk !!
I have case lengths from 2.004 all the way thru to 2.027 and every stop in between.


Cheers.
Click to expand...

The fired cases were all 2.010? I would almost think that in itself was odd. Were they measured after firing, and before resizing? Or measured after resizing.
 
ok the case OAL has nothing to do with head space, so no your #### won't fall off.
a lot of comercial mid range grade brass isn't the best so the streach on the neck veries between rounds.

Ive seen federal brass streach over 8 thou in a tight tikka chamber. I can only imagine how much it could strech in a loosy goosy norc. As for the shrinking... that happens, the case popped outwords enough it sucked back the neck.....thats a lttle more concerning ....
 
Check your primer corners for signs of variable powder charge. I hate factory ammo, some may be flattened right out at the corners, some will be rounded like they were lower pressure.

Like Lord EP said, COAL isn't a good indicator. Get your callipers out and check rim to shoulder, it should be more consistent. When you trim your brass and start reloading, things might settle down.

Also, how many round have you put through you 305? Are these the first rounds through it?
 
saskgunowner101 said:
The fired cases were all 2.010? I would almost think that in itself was odd. Were they measured after firing, and before resizing? Or measured after resizing.
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The cases were all 2.010 out of the box prior to firing. Measured again after firing just to see what was going on. I thought brand new virgin brass would give me a good idea of what was going on. As soon as I can get photobucket working I will post pics of all 40 rounds with the primers
 
The case legth does not matter much as it will change after siseing and all trimmed the same what you need to measure is the base to dantum line with the hornady pice that attaches to the calipers !
 
You will observe the stretch after you resize the fired cases. All you have measured is the before and after firing right? If the shoulder moved forward and the case expanded in diameter, it is understandable that the length might shorten.

Imagine a fire cracker going off inside an aluminum beer can. The walls bulge out and can appears shorter.

But after you iron out that expansion to the proper diameter through resizing, the stretch will be evident.
 
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crashcollins said:
Holy hell man! Read the stickies or something. LOL
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Your probly on to somthing!
But truly I prefer to be outside shooting things rather than sitting infront of the comp posting useless cheeky coments! :p. Oops I just posted a useless cheeky comment! Must be contagious! Haha :p
 
Finally got photobucket working. These are the 40 rounds fired. I would appreciate very much any opinions from more knowledgeable eyes than mine.
I suspect hat at least 4 or 5 of these are showing pressure signs, which ties in with what I heard and felt at the range. I know pple will say its impossible to hear a difference or feel a difference, but when you shoot 40 "identical" rounds the differences are apparent.
I have measured all the cases from the rim to the shoulder and they all come in at 1.712, but I could be measuring at the wrong point so I measured at the other end of the shoulder and they came out at 1.571. Only rough masurements with calipers to see if there was any significant difference between cases.



Thanks for taking the time to have a look :)
 
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