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Reloading Forum >
80gr. Bullets in 1:14 Twist
80gr. Bullets in 1:14 Twist
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waterdog
2 posts
Sep 17, 2004
9:22 AM
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I have a 10.5lb Sporter chambered for a 6BR with a 14 twist Hart barrel. Some of us were discussing whether it would stabilize 80gr. Fowler bullets at 600yds, so we decided to try it in a match. I had a week to try to work up some kind of load. I tried Varget, Benchmark, N-135 and N140 and all of them shot decent at 100yds. The N-140 gave me 3120fps with an extreme spread of 9, so that is the load I used.
We didn't know if the bullets would go straight or keyhole at that distance, but they shot straight. My best group at 600yds was 2.2 inches. I am going to work on some more loads and see if something better can be developed.
If you have a BR with a 14 twist barrel and want to try it at 500 or 600yds, it should stabilize 80gr. bullets. If anyone else has tried this, please share your results with us.
Larry Isenhour
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jb1000br
8 posts
Sep 17, 2004
10:27 AM
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man those things must be on the ragged adge!! So with that hart barrel it is probably actually a little over 1:14--WOW!
BTW--nice group!!
JB
Last Edited by jb1000br on Sep 17, 2004 10:28 AM
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JoeR
3 posts
Oct 01, 2004
11:58 AM
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Waterdog;
Thanks for the info on the Fowler 80s, I have been shooting Berger 74s in my 14 Twist 6br and was wondering about the 80 Fowlers... If it will shoot the 80s at 600 near as good as the 74s do at 500 I will have a 600yd F-class to go with my 1000yd F-class gun...We have been shooting mostly 1000 but are going to start shooting 600 also, I think. ...Thanks a lot and... Have a good .1"...Tater...
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waterdog
3 posts
Oct 04, 2004
7:45 AM
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Joe,,,,,,,,,,,I have been working with N-135 and came up with a couple of good loads. I could get over 3200fps but my gun didn't group as good at that speed. The load I settled on was 31.2gr of N-135 with a MV of 3158fps. It grouped great at 100yds. Our last 600yd match is Oct. 30 and it will be cooler, so we will see if these 80 Fowler's will still group at 600yds in the cooler temperatures.
This gun is chambered for the 6BR Norma with a .274 neck. Barrel is 24 inches.
When you try these bullets, please let us know your results. If my results weren't "just a fluke" and we find these bullets will stabilize in a 14 twist barrel, it opens up a whole new ball game for BR shooters with 14 twist barrels. Jef Fowler makes some of the best bullets available.
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HBC
Ballistics Editor
22 posts
Nov 24, 2004
5:21 PM
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Larry,
Very interesting that a 14" twist will stabalize a 6mm, 80 grain Fowler at around 3120 f/s.
Here are the dimensions on the 80 grain Fowler provided to me by Rich DeSimone:
meplat diameter 0.077" dia.
ogive length 0.570"
bullet length 0.919"
depth to top of core 0.284"
core weight 55.3 grains
Jacket thickness:
near base of ogive 0.018"
center of bearing 0.020"
base 0.018"
Based on that data, a 14" twist barrel should not work well with the 6mm, 80 grain Fowler unless fired at a higher elevation above sea level.
If you don't mind, what elevation and temperature did you get the good groups out of your Hart barrel with the 80 grain Fowlers at 600 yards?
Have you actually measured the twist of that Hart Barrel, and if so what were the results, please?
I am always looking for field data and your's would definately be interesting.
Henry
Rev.: Confirmed that Rich provided dimensions. Added jacket thickness.
Last Edited by HBC on Nov 24, 2004 6:15 PM
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waterdog
8 posts
Dec 04, 2004
5:42 PM
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HBC,,,,,I shot the 80 Fowlers in two matches at Piedmont. I don't know the elevation of the range,(probably around 1600 feet). The loads were developed at my home and the elevation here is 3200 feet above sea level.
The temperature at Piedmont during the last match was somewhere in the 60's I think.
I haven't checked the actual twist of the Hart barrel, but I will and let you know the results.
Sorry I haven't replied sooner, but I have been in PA doing some deer hunting. I took this gun with me to let my friends there do some shooting with it. We shot it at 500 yds with good success breaking lot's of clay birds. The elevation there is 1200 feet and the temperature was in the low 40's.
Larry
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HBC
Ballistics Editor
23 posts
Dec 05, 2004
12:15 PM
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Larry,
Thanks for the additional information. Look forward to your twist measurement results.
The data for Pennsylvania at 1200 ft. AMSL and low 40s, muz. vel. of 3120 f/s for the 6mm, 80 grain Fowler and a true 14" twist: I would expect very large amounts of yaw at about 7 yards with the bullet settling down at about 100 yards or a little further but shooting very poor groups at that range and 600 yards for that matter.
A 12" twist should shoot that load very well for the above conditions and even a 12.3" twist should do ok but an 11" twist would be a better choice.
Henry
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waterdog
9 posts
Dec 05, 2004
3:40 PM
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Henry,,,,,Let's go to the new forum with this discussion. The Moderator wants us to move.
Larry
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ourway77
2 posts
Feb 28, 2009
8:08 AM
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I have a shilen OTT 16-1/4" 6BR 1 in 14 tried 80 grin bullets. They were all over the target entering side ways. Dropped too 75 grain Hornady V-max, What a difference.[IMG]http://img.photobucket.com/albums/v401/ourway7/HPIM1172.jpg[/IMG]
Last Edited by on Sep 04, 2009 4:44 AM
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