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March 23, 2014, 07:41 AM | #26 | |
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That's a good micrometer and the price is excellent. Once you get it, you'll be glad you spent the money. I also have the outside micrometer, but I'm a bit of a tool junkie.
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March 23, 2014, 10:45 AM | #27 | |
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last round I fired was not extracted
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March 23, 2014, 12:38 PM | #28 |
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243winxb that's what I was thinking as well, however, after I was able to extractor the case, once it was rechambered it stuck again. The only thing I can think of is the case expands and doesn't contract enough because it's been hardened.
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March 23, 2014, 04:42 PM | #29 |
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I use a standard vernier caliper to measure case neck wall thickness. It's as accurate as a ball micrometer and has a lot more applications. Comparing its readings to a borrowed ball micrometer, the difference was no more than .0001".
You've done good by geting your die set right to bump shoulder back just right. And a .003" spread in case headspace across a batch of cases is normal due to the amount and type of lube that's on each case. Most of that spread's caused by the press springing up with a case all the way up in a sizing die then pulling the die back down on the case a bit before you lower the ram and pull the case out of the die. Using competition shell holders from Redding will help as the one of the right height used and the sizing die stopping hard against it when full length sizing and setting shoulders back it's more consistant in sizing the case. Or, when the ram's all the way up with the case full into the die, let the press set for several seconds and the press' springing will contract and pull the die back down further on the case. Commercial match ammo has about the same spread in its case headspace and that doesn't cause any significant accuracy problems. That's case dimension consistancy is least important of all for best accuracy. |
March 23, 2014, 05:10 PM | #30 |
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Thanks guys. Feeling good about where this ended up.
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March 25, 2014, 10:25 AM | #31 |
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This is very interesting to me, as I just started loading for a M1-A. My best friend just bought one. It just happened that my son scarfed up some once fired LC .308 off the firing range while training with the Army reserve. It had been fired in a 240-bravo machine gun. A 50 cal ammo can full of brass, a few belt clips and a few stones.
Interesting to see the wide variation in length of the fired rounds. I asked him if it were possible that they had been fired in more than one weapon, he said very possible. The fired shells measured from not needing any trimming,(under 2.015) to 2.040! Of course that's after sizing. First step was to decap, I'm using a dillon 650 to load them. So an empty tool head was put in with just a lee decapper die in it. (After a trip through my vib-tumbler to get the range grit off the brass, and sort the belt links). This allowed the use of the case feeder to quickly decap. Then sitting watching a movie, using a cordless drill with a Hornady primer crimp cutter in it. Then switching to a Hornady .308 size die set with a Wilson case gauge to the low step to insure the shells would chamber, as I didn't have the rifle to check, and it hadn't even been picked up at the gun shop yet. Then trimmed with the lee system, and chamfered with a VLD inside, and a lee outside. Loaded 100 with Hornady 130 spire points to mid level loads using WC-844 and winchester LR primers. He showed up on Saturday with the rifle, it's a beauty. Went directly to a range and put about 50 rounds of that ammo through it. Now, having fired cases from the rifle, I used my RCBS precision mic to measure them. Fired cases miced out at + .003 over zero. I then set the FL sizer die to set the shoulder back to -.004. I figure that give some wiggle room in case some brass springs back, the shell will still chamber. This resulted in less shoulder bump back than with the die tight against the shell plate. I also have some 150 gr. core-loct remmys and he brought out some Hornady 165 interlock pointy bullets. Once the rifle is broke in, I have some Sierra palma 155 match bullets to work up a load for. I also have some S-168 match kings to try out. His rifle has a rail like a Weaver scope base in front of the receiver so that a medium eye relief scope could be mounted, or any of the red-dots.
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March 25, 2014, 02:54 PM | #32 | |
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http://www.travers.com/57-101-430?Ca...FWxp7AodK2IAXQ |
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March 25, 2014, 05:10 PM | #33 |
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Snuffy sounds like an m1a scout. Fwiw I have one and love it. Favorite rifle.
Let me know if that military brass becomes to much work to decrimp and trim. :-) Mil thanks, I have heard they can be difficult to manipulate. |
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