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.3115" 170grn M30 bullets |
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Goosic 
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Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8842 |
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 Topic: .3115" 170grn M30 bulletsPosted: August 23 2023 at 3:30pm |
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I have been working on creating a target load for my Custom No4 Maltby. The bullets I was given to work with are 170grn FMJ-BT, .3115" diameter, have a sectional density of 0.265 and a coefficient of .460 @ 2500 fps or above.
Using extrapolated data, I have chosen to start with 41.0grn of VihtaVuori N540 which should yield a fps of 2495 - 2550. The C.O.L. of .3111" seats the bullets just past its cannelure but still allows for reliable feeding from the magazine. This also puts the bullet .030" from the rifling on my rifle; "It has a M47C BSA barrel on a Maltby reciever." If I have done everything correctly, this round should be as accurate as the .308W using the 168grn Sierra HPBT Match King. I plan on testing this load this weekend...
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Honkytonk
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Joined: December 30 2017 Location: Brandon Mb Status: Offline Points: 5190 |
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Posted: August 23 2023 at 3:44pm |
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Nice looking round!
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Sapper740
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Joined: July 15 2021 Location: Texas Status: Offline Points: 1737 |
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Posted: August 24 2023 at 2:23am |
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Should be a decent combination, you're right in the sweet spot for Varget and BL-C(2). N540 is only slightly slower burning.. Much airspace in the case?
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Goosic
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Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8842 |
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Posted: August 24 2023 at 6:37am |
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Sapper740: 80% - 85% case fill. I dropped the charge to 40.9grns or more specifically 2.65 grams and yes, I am weighing out each charge. I am playing with the unknown here and want to be as precise as possible. The slow burning N540 has me convinced to use Federal GM215M primers to assist with a more complete burn as well.
I think some visuals are in order here. Post Script: The ONLY thing I know about the cartridge cases are that they supposedly were made in Canada somewhere. I have 77 unfired cases currently...
  
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britrifles
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Posted: August 24 2023 at 11:58am |
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VhitaVuori website gives a max charge of 42.9 gr N540 with the 174 gr Sierra HPBT (likely a typo in their data, they list the bullet as 175 gr) and a standard Large Rifle primer. Your load should be fine.
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Goosic
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Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8842 |
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Posted: August 24 2023 at 12:26pm |
Geoff:
You do understand that I am using a (.3115" 170grn FMJ-BT) projectile that is intended for the 7.62x54R correct? The VihtaVuori 2023 reloading guide that I have does indeed give a maximum charge weight of 42.9grns forbthe .303 British when using the N540 smokeless powder with a 174grn BTHP Sierra Match King but again, I am using a 170grn M30 FMJ-BT projectile designed for the 7.62x54R...   |
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britrifles
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Posted: August 24 2023 at 4:02pm |
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Yup, sure do. SMK is .311 diameter, and slightly heavier. You will be fine, no need to worry.
Generally, it is advisable to drop max charge by one grain when substituting a magnum primer for a standard primer. But, at the charge weight you’re using, it’s fine.
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britrifles wrote: