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Understanding ubiquitous data?

non mortuusnon mortuus Member Posts: 649 ✭✭✭✭
When given data is very general... say "180gr jacketed bullets", what should sort of unwritten conditions(?) should I assume to this data?
Is this data for flat base bullets boat tail?
I was looking up some rifle loads for 303Brit for 180gr bullets. Happens I have a box of 180gr 'round nose', and some are 180gr pointed 'spitzer' type bullets [?][?]

Comments

  • bpostbpost Member Posts: 32,669 ✭✭✭✭
    edited November -1
    As long as you start with a reasonable middle of the list charge weight and work up you will be OK. The bearing length and jacket material will determine the friction in the bore. Each 180 grain bullet you have might vary a bit but not enough to make a difference at normal pressures.
  • MEMPHISJOEMEMPHISJOE Member Posts: 185 ✭✭✭
    edited November -1
    quote:Originally posted by non mortuus
    When given data is very general... say "180gr jacketed bullets", what should sort of unwritten conditions(?) should I assume to this data?
    Is this data for flat base bullets boat tail?
    I was looking up some rifle loads for 303Brit for 180gr bullets. Happens I have a box of 180gr 'round nose', and some are 180gr pointed 'spitzer' type bullets [?][?]

    Do not assume that all bullets of the same weight are safe to use because one of that weight worked within limits. For example a Barns bullet has much more engraved area for that same weight as does a lead core projectile, shape and material used in the construction is critical. Imagine using a 180 all copper, with a different type of brass (with a smaller cap), a hotter primer etc, you can and will get into a over pressure situation. There is good loading data out there for almost every projectile produced, the best advice, is take two minutes on the computer and find the data.
  • RCrosbyRCrosby Member Posts: 3,808 ✭✭✭
    edited November -1
    A good rule of thumb, especially if you're already working with loads that approximate factory velocity/pressure or more, is to drop back down whenever you change a component; whether that change is brass, primer, or bullet, and then work your way back up.
  • non mortuusnon mortuus Member Posts: 649 ✭✭✭✭
    edited November -1
    quote:Originally posted by MEMPHISJOE
    quote:Originally posted by non mortuus
    When given data is very general... say "180gr jacketed bullets", what should sort of unwritten conditions(?) should I assume to this data?
    Is this data for flat base bullets boat tail?
    I was looking up some rifle loads for 303Brit for 180gr bullets. Happens I have a box of 180gr 'round nose', and some are 180gr pointed 'spitzer' type bullets [?][?]

    Do not assume that all bullets of the same weight are safe to use because one of that weight worked within limits. For example a Barns bullet has much more engraved area for that same weight as does a lead core projectile, shape and material used in the construction is critical. Imagine using a 180 all copper, with a different type of brass (with a smaller cap), a hotter primer etc, you can and will get into a over pressure situation. There is good loading data out there for almost every projectile produced, the best advice, is take two minutes on the computer and find the data.

    Thats kinda what is bothering me. Some data is specfic to one certain brand/weight/design and that's great for proj's & data I can match up. While other bullets I can't find (old, weird, cheap imports??) data for, and the only thing that seems to apply is data for just '180 grain jacketed' [V]
  • bpostbpost Member Posts: 32,669 ✭✭✭✭
    edited November -1
    When the load book lists a generic charge with a broad based statement like "180gr jacketed bullets", You are safe in shooting that load in your rifle. Of course ALL manuals have the recommendation to start low and work up from there. There is enough "fudge factor" in loading that as long as you start low and keep an eye out for pressure issues you will be OK.

    Example; I have hundreds of the same bullet weight you used in a large box. They are all mixed .3078-.309 diameter bullets weighing from 174 to about 185 grains. I load them for plinkers in a 30-06 with 46 grains of IMR-4895 powder. That is a low to middle of the road load for that range of bullet weight in a 30-06. They all go BANG with no problems or pressure issues in mixed brass.
  • MEMPHISJOEMEMPHISJOE Member Posts: 185 ✭✭✭
    edited November -1
    quote:Originally posted by bpost1958
    When the load book lists a generic charge with a broad based statement like "180gr jacketed bullets", You are safe in shooting that load in your rifle. Of course ALL manuals have the recommendation to start low and work up from there. There is enough "fudge factor" in loading that as long as you start low and keep an eye out for pressure issues you will be OK.

    Example; I have hundreds of the same bullet weight you used in a large box. They are all mixed .3078-.309 diameter bullets weighing from 174 to about 185 grains. I load them for plinkers in a 30-06 with 46 grains of IMR-4895 powder. That is a low to middle of the road load for that range of bullet weight in a 30-06. They all go BANG with no problems or pressure issues in mixed brass.
    This is good advice! May I add, if you run into data that says "jacketed bullet, any brass, any primer, oal within spec, but this exact amount of powder" throw that "data" out, it was written by the unknowing for the unknowing!
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