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Goosic
Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8792 |
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Posted: January 09 2020 at 9:44am |
I must preface this by stating that I do not recommend that anyone attempt to duplicate my findings. I went to the range yesterday and ran my test of firing .308 diameter, 180grn Norma Vulkan bullets through a .303 two groove barrel,comparing those with .312 diameter 174grn Hornady BTHP bullets.
The specifics are: All tests were done at a distance of 100 yards!!! Rifle: 1942 No4MkI* Long Branch with new barrel. Headspaced correctly, using a Forster .070" field gauge Bore diameter between the lands are .3035" Hornady 303B cases trimmed to 2.212" with an average rim thickness of .0585" Test batch #1: .308 180grn Norma Vulkan bullets loaded with 40.0grns of Norma 202,primed with WLRM primers with a C.O.L. of 2.992" Test batch #2: .312 174grn BTHP Hornady bullets loaded with 40.0grns of Norma 202,primed with WLRM primers with a C.O.L. of 2.933" The results show a very minimal tighter grouping with the .308 Vulkan and they hit higher on the target then the lighter 174grn BTHP bullets. I did not include the two extreme outside shots in the measurements because those were my allowed sight in shots per test batch. The overall comparison between the two rounds show no discernible differences when firing a .308 caliber bullet through a. 303 British Enfield rifle. |
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Shamu
Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 17603 |
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Interesting! How well did they sit in the larger ID neck?
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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)
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Goosic
Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8792 |
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I ran .020"- .0230" of the opening into my .308 die and then used a .303 factory crimping tool to finalize the process.
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Shamu
Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 17603 |
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Ahh I don't crimp.
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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)
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philtno
Senior Member Joined: May 04 2019 Location: Blenheim, NZ Status: Offline Points: 261 |
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Nice shooting Goosic!!
Question: Could the lack of significant difference in the groupings between the two rounds come from the fact that it's a new barrel??
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Pukka Bundook
Senior Member Joined: February 02 2015 Location: Canada Status: Offline Points: 1369 |
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Goosic,
I have been doing the same with .308" in the Finn M/24 Mosin Nagant, and have the same results. I'd love you to try the Lapua D-46, (185 gr) Or the D-166, (200 gr) in the .303. I have a bit of advantage in that the RCBS dies for my rifle come with two neck expanders, for .308" or .311/12" Very nice shooting by the way! Very interesting topic to me as well!! |
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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Even if you include the two "fliers" in the groups, the results are still very good.
I see the .308 bullets look spread more vertical. Or were these the first two shots with sight adjustments made after each? Any thoughts on this behavior? This might explain why some barrels still group well even after lands are worn to .305, or more! Although you suggested we don't "attempt to duplicate" your findings, I might have to see how the .308 bullets shoot in my LB No. 4 five groove, but I don't think I could shoot 1 MOA groups (maybe for 8/10 shots on some groups if I got lucky). |
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Goosic
Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8792 |
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I have yet to locate a supplier of the D 166.
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Goosic
Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8792 |
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The very first shot for the Vulkan is the one at the very top. I held to the six o'clock and that was the placement. I tried to compensate and aimed farther south and placed the second shot in the black at the six o'clock. The remaining shots, I aimed at the second shot .
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Stanforth
Senior Member Joined: January 08 2017 Location: Oxford England Status: Offline Points: 773 |
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I bet you could get a MOA group using only your bayonet..
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Life.. a sexually transmitted condition that is invariably fatal.
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