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Don Fischer
Joined: 24 Mar 2005
Posts: 2503
Location: Antelope, Ore
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| Posted: Thu Sep 10, 2009 5:47 pm Post subject: About bug holes |
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I started fooling with my 25-06 today with 100 gr SMK bullet's and setting FL dies to partical re-size with a feeler guage. The idea being to make the setting up of FL dies for that operation much less complicated. I only recommend partical re-sizing on belted and rimmed cases to make those cases head space on the shoulder rather than the belt or the rim.
Well I tried with my .243 and found out that to partical re-size with it, the die needs to be .001" off the shell holder. That don't show much! So I decided to try with my 25-06 and got bullet's to do it with yesterday, 100gr SMK's.
Got out a box of MTY but primed FL cases and made four try loads up to max listed for IMR 4350. Those cases will get partical resized and soon as they won't chamber after being fired anymore, go to the feeler guage to set the die.
Went to the gravel pit where I do a lot of 100yd shooting and set up. Shot at 100yds from a bench and off a sand bag rest. Got to the fourth group, listed max load, and pulled the first shot, knew it when I did it. 1st shot was 3/4" low and 3/4" right of the second shot. Went back and fired another, then walked down to look while the barrel colled. Missed the target completely! Couldn't possibly be but there it was. Went back and fired one more and walked down again. 4th shot opened the 2nd shot just barely and I mean barely. Huh! Fired the 5th shot and could see the hole moved just a smidge.
Got home and looked at the back of the target and could see the paper torn a bit more than one hole would do. So got the calipers out and measured the widest point best I could eyeballing. .368"! That's more than one hole. Take away one dia, .257, and that leaves a group size c to c of .111". Nothing special, do it all the time! Yea right. I'll take a picture of this this and post it tomorrow, I still have a hard time believeing this and the target is right here.
BTW, I'm still gonna try the experimant with this rifle. Then I'll probably get back to this load! |
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Don Fischer
Joined: 24 Mar 2005
Posts: 2503
Location: Antelope, Ore
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| Posted: Thu Sep 10, 2009 6:58 pm Post subject: |
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Here it is!
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ChesterGolf
Joined: 17 Aug 2002
Posts: 1825
Location: Nova Scotia
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| Posted: Fri Sep 11, 2009 5:06 am Post subject: |
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| Looking good Don. Was that with the FL cases or the new PL cases? |
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Don Fischer
Joined: 24 Mar 2005
Posts: 2503
Location: Antelope, Ore
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| Posted: Fri Sep 11, 2009 8:46 am Post subject: |
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| That was with a full length case. Going back out today and shoot up 20rds with the same cases and old Herter bullet's. Once I get the cases where they won't chamber unless FL sized, I'm gonna take them down with the feeler guage and see what happens. |
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ChesterGolf
Joined: 17 Aug 2002
Posts: 1825
Location: Nova Scotia
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| Posted: Fri Sep 11, 2009 12:46 pm Post subject: |
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| So what is the perceived advantage to the partial sizing? More case life? I don't think you are going to get much more accuracy from that load! :thumbsup1: |
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Don Fischer
Joined: 24 Mar 2005
Posts: 2503
Location: Antelope, Ore
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| Posted: Fri Sep 11, 2009 1:38 pm Post subject: |
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I haven't been a fan of partcial sizing except for belted and rimed cartridges. Then you can change ti headspace from the belt or rim to the shoulder. Both belted and rimmed cases have pretty sloppy chambers. With them you see case head seperation start just in front of the head in the form of a bright ring.
With rimless cartridges the story changes. They do headspace on the shoulder and streach isn't near the problem. I've heard a lot of people claim better accuracy with partcial sized cases but the gain, if any, never seemed worth the time taken to adjust the dies for it. Then a couple rounds and your back to a FL re-size to get the case to chamber. Guy on another site claims it's the only way to go. He say's properly done you'll bump the shoulder back just a bit every time. Maybe so. In fact I'm sure if you did you wouldn't have to FL size again, for that rifle. But if you use that preset die for another rifle, them you have to go through nto whole setup process again to gain what, maybe a quarter inch? That's not much on a hunting rifle and a macth chamber fits to well to worry about it.
I do think it would be good to set the die to bump the shoulder just a bit, might get a few extra loadings out of a case. But a few extra loadings still doesn't justify the trouble to me. Then if you do change the die for another firearm, How do you get the same setting again with 14 tpi threads? Gotta be nerve wracking. But if you could get the setting once through the use of a feeler guage it would be simple to reproduce it at any time.
This is all just an experiment for me as I really don't think its worth the trouble. If it were everybody would have FL and neck sizing dies for all their cartridges. Then again if the die could be set up quickly and exactly evertime with the feeler guage, that might be worth it. |
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