#1
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20 VT high pressure
Winchester brass fireforming load 20.3gr AA2200 - 40 rounds fired (65 degrees) with no issue when one round - heavy bolt lift and stuck to the bolt. Same load last year (about 75 degrees) 1 round out of 300 blew a primer.
What could be the cause of this seemingly random issue? I weigh every charge from the same lot of powder. thanks |
#2
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Is your brass made from Winchester .223 Rem brass? What bullet are you using?
If your brass is from Winchester .223 Rem then it is probably thicker and has less case capacity than the Remington .221 Fireball brass Western Powders used to test their loads. You are probably using a powder charge that is too hot. Using Remington .221 Fireball brass and the Sierra 32 gr. BlitzKing bullet, Western's max charge of A-2200 is 20.0 grains for 3758 fps at 60,928 psi. You can get Western Powders load guide in PDF form here: http://www.accuratepowder.com/load-data/ This might help too: http://www.saubier.com/forum/showpos...1&postcount=16 |
#3
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Two 40grain bullets among 340-32grain?
case length too long? case neck diameter out of bounds? Too much fouling in neck area of chamber?
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#4
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My guess is headspace issue with new brass, I had this problem with some 221 FB brass with my brothers 20 VT.
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#5
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neck thickness
heavy case slightly heavier powder charge ( some digital scales can drift) case length to long and it is crimping the bullet bore fouled temperature change from when load was worked up and you are on the ragged edge of excess pressure combined with any of the above list. I had a Shilen 17 barrel that shot lights out for about 40 rounds and then it would start blowing primers. clean the barrel and you were good for another 40 rounds. sent the barrel back to Shilen and they said there was a tight spot half way down the bore. lapped the barrel and didn't have anymore problems. I would check all the above and then back the load off .5 gr and if it shoots well try another 300 rounds
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#6
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Quote:
32 grain Z-Max bullet. Looking closely the stuck case was R-P. The one last year was either LC or Norma FB brass. The neck thickness on the stuck case is similar to my other neck turned brass so I don't think I missed turning the neck. All cases trimmed appropriately. Wouldn't sticky extraction or flattened primers show up before sticking a case or blowing a primer? Headspace - would too little cause the issue? I will measure each one before loading to verifty. Thanks -I will back off a little on the charge. Last edited by SmittyWerben; 03-29-2019 at 02:31 PM. |
#7
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My problem with the R-P brass was they were .010 short, but being to long can be a problem. You should feel some resistance on brass that is to long.
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#8
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For whatever reason the photo just appears to show a classic overload issue. Somehow this one round was overloaded.
However the one post saying the max load for the standard 20VT is 20 grain or under is correct. I would find a accurate load a little lower than 20.3 of A2200. Play safe and sane. Bill K |
#9
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Quote:
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#10
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Is the click at the beginning of the bolt lift or the end?
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