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Thread: comparing flatshooting calibres

  1. #1

    comparing flatshooting calibres

    When comparing bullet drop at 300m ( as an example ) for diffrent calibres, we must start from the same point. For any calibre a max high shot at 100 m must be determined. RWS use max 4 cm high at 100m, which is about 1.6". When using this 1.6" high at 100 m as a maximum for all calibres, the drop at 300m can be very diffrent. If we can believe the catalogues a 150/160 grain 308 can drop from 3 to 5 inches more than a 130/140 grain 270 bullet. This can be the diffrence between a dead animal and a broken leg.

  2. #2
    Quote Originally Posted by Hales Smut View Post
    When comparing bullet drop at 300m ( as an example ) for diffrent calibres, we must start from the same point. For any calibre a max high shot at 100 m must be determined. RWS use max 4 cm high at 100m, which is about 1.6". When using this 1.6" high at 100 m as a maximum for all calibres, the drop at 300m can be very diffrent. If we can believe the catalogues a 150/160 grain 308 can drop from 3 to 5 inches more than a 130/140 grain 270 bullet. This can be the diffrence between a dead animal and a broken leg.
    where did you read that?

    Flatness is marketing hype unless you are shooting beyond stalking ranges.

    if you exclude the 4000fps varmint calibres and the Ultra Magnums 90% of deer legal calibres when zeroed +1" at 100yds will be there or there abouts at 200yds and around 6-8" at 300 yds

    Norma 130gr .270 is +1.3, 0, +6.4" for 100, 200 and 300yds http://www.norma.cc/en/Products/Hunt...er/Soft-Point/
    Hornday 150gr 308 is +1.6, 0 and 7.2" at 100, 200 and 300yds http://www.hornady.com/store/308-Win...superformance/

    I know I cant shoot well enough to put down a 1.2" difference at 300yds to the "flatness" of the calibre I am shooting. more chance its just my shooting!

    almost all of these calibres have a 4" MPBR of with +/-30yds with very few exceptions
    the only exceptions are breaking 3100-3200fps MV

    http://www.chuckhawks.com/rifle_trajectory_table.htm

    .243 Win. (95 BT at 3100)* .379 +2.5" +2.3" 3"@150 300
    .243 Win. (100 Sp at 2960) .351 +2.6" +1.9" 3"@140 283
    6mm Rem. (100 Sp at 3100) .351 +2.5" +2.2" 3"@150 296
    .243 WSSM (100 Sp at 3100) .351 +2.5" +2.2" 3"@150 296
    .240 Apex (100 Sp at 2900) .351 +2.6" +1.8" 3"@135 278
    6x62mm Freres (100 Sp at 3300) .351 +2.4" +2.5" 3"@150 312
    .250 Sav. (100 Sp at 2820) .336 +2.7" +1.6" 3"@125 270
    .257 Roberts (100 Sp at 3000) .336 +2.6" +2.0" 3"@150 286
    .257 Roberts (120 Sp at 2780) .391 +2.7" +1.6" 3"@125 271
    .257 Rob. Imp. (115 BT at 2900) .453 +2.6" +1.9" 3"@140 286
    .25 WSSM (120 Sp at 2990) .391 +2.5" +2.0" 3"@145 291
    .25-06 Rem. (100 Sp at 3210) .336 +2.5" +2.4" 3"@150 305
    .25-06 Rem. (120 Sp at 2990) .391 +2.5" +2.0" 3"@145 291
    6.5x54 (140 PSP at 2400) .435 +2.9" +0.2" 3"@115 238
    6.5x55 (125 NP at 2875) .449 +2.6" +1.9" 3"@135 284
    6.5x55 (140 Sp at 2645) .435 +2.7" +1.2" 3"@125 260
    6.5x57 (140 SP at 2740) .465 +2.7" +1.6" 3"@130 272
    .260 Rem. (120 Sp at 2890) .433 +2.6" +1.9" 3"@135 284
    .260 Rem. (140 Sp at 2750) .435 +2.7" +1.6" 3"@125 271
    6.5-284 Norma (140 PSP at 2900) .435 +2.6" +2.0" 3"@140 286
    6.5mm Rem. Mag. (140 PSP at 2900) .435 +2.6" +2.0" 3"@140 286
    6.5x65 RWS (127 Sp at 3313) .449 +2.4" +2.6" 3"@160 323
    6.5x68 S (140 Sp at 2990) .435 +2.6" +2.1" 3"@150 294
    .264 Win. Mag. (120 Sp at 3300) .433 +2.4" +2.6" 3"@160 321
    .264 Win. Mag. (140 Sp at 3100) .435 +2.5" +2.3" 3"@150 303
    6.8mm Rem. SPC (110 BTSP at 2500) .360 +2.9" +0.5" 3"@125 243
    6.8mm Rem. SPC (115 Sp at 2800) .325 +2.6" +1.3" 3"@130 267
    .270 Win. (130 Sp at 3140) .416 +2.5" +2.4" 3"@150 305
    .270 Win. (140 AB at 2950) .496 +2.6" +2.1" 3"@140 293
    .270 Win. (150 Sp at 2900) .481 +2.6" +2.0" 3"@138 287
    .270 WSM (130 Sp at 3206) .416 +2.4" +2.4" 3"@150 311
    .270 WSM (150 Sp at 3150) .481 +2.5" +2.4" 3"@150 311
    .270 Wby. Mag. (130 Sp at 3375) .416 +2.3" +2.6" 3"@150 326
    .270 Wby. Mag. (150 Sp at 3245) .481 +2.4" +2.6" 3"@160 320
    7-30 Waters (120 FP at 2700) .195 +2.9" +0.4" 3"@125 238
    7x57 (140 BT at 2660) .485 +2.7" +1.3" 3"@125 264
    7x57 (175 Sp at 2540) .519 +2.8" +1.0" 3"@125 256
    7mm-08 Rem. (120 Sp at 3000) .343 +2.6" +2.0" 3"@140 287
    7mm-08 Rem. (140 BT at 2860) .485 +2.6" +1.9" 3"@140 285
    7x64 (140 BT at 3000) .485 +2.6" +2.2" 3"@150 298
    7x65R (175 Sp at 2650) .465 +2.7" +1.3" 3"@125 262
    .284 Win. (150 Sp at 2750) .456 +2.7" +1.6" 3"@130 272
    .280 Rem. (140 BT at 3000) .485 +2.6" +2.2" 3"@150 298
    .280 Rem. (160 Sp at 2890) .475 +2.6" +1.9" 3"@140 287
    .300 Sav. (150 BT at 2630) .435 +2.8" +1.2" 3"@125 259
    .307 Win. (150 FP at 2600) .268 +2.8" +0.5" 3"@120 243
    .308 Marlin (160 EVO at 2660)* .400 +2.8" +1.2" 3"@130 261
    .308 Win. (150 BT at 2800) .435 +2.7" +1.7" 3"@135 275
    .308 Win. (165 Sp at 2700) .410 +2.7" +1.3" 3"@130 264
    .308 Win. (180 Sp at 2610) .483 +2.8" +1.2" 3"@125 259
    .30-06 (150 BT at 2910) .435 +2.6" +2.0" 3"@145 287
    .30-06 (165 Sp at 2800) .410 +2.7" +1.7" 3"@135 273
    .30-06 (180 Sp at 2700) .483 +2.7" +1.5" 3"@125 269

  3. #3
    Just the printed Norma catalogue that I picked up at the small Belgian Game Fair this year.

    Just checked RWS ammo. Both KS bullet.
    270 / 130 grain / + 4cm at 100 m / - 27,4 cm at 300m
    308 / 165 grain / + 4 cm at 100m / - 41,6 cm at 300m
    diffrence is 14,2 cm or 5.5 inch.

    That superformance is not representive I think? I plan to buy a 308 to stalk and pratice on the range. ( Cheap training ammo as I do not reload )
    I agree that flatshooting is not everything, but it probably makes life easier if it's difficult judging the distance.

    My point is that if you zero your rifle so that the bullet never rises above 1,5" above the line of sight the diffrence in drop of the bullet becomes more important with the slower calibres.

  4. #4
    No need to judge distance anymore,rangefinders all the rage

  5. #5
    I would prefer to check the real MV of the bullet out of my rifle.
    Sometimes ammo manufacturers show off a bit with figures. In one case they use data from a 29" barrel. (With hunting ammo)
    Either way, it shows neither the 308 nor the mighty 270 can be point and shoot to 300m.
    If one shoots at game above 200m the safest is to laser the distance and adjust scope. Second best is hold over dots or lines on
    a FFP scope. Hold over points on a second focal plane would be too risky for me.
    edi

  6. #6
    As I don't handload I have to trust the data given in the ammo catalogues. My first rifle to buy will be a 308 for the knwon reasons. I just think when you take into account human errror when shooting, the less bullet drop the easier it is to get the bullet in the vital parts. At 300 metres all calibres will need compensation. I also think it's better to avoid shooting at 300m , but that's one of the data you find in the catalogues.
    Edi, do you have any idea how those mil dots compare to the traditional n 4 in low light? Are they thick enough to be visible with slightly older eyes?

  7. #7
    Possibly better than trusting the data on the ammo box is to have a rifle 100% zeroed at 100m or yds and then see how many clicks are needed
    to hit your 300m or yds target. Try get the average and make up a drop chart from that data. Might have to use the bc that the catologue
    uses but the speed you reverse find out with a ballistic program.
    You'll be astonished how accurate it is at say 250 or 350 after dialing in.
    The reticles are different on almost all scopes. Must check individually on the scope spec. FFP/SFP and the width of the lines at x distance and mag.
    Had a 4-16x50 S&B varmint reticle with, If I remember right 4mm at 100m line thickness. When set at 4 mag I couldn't see a thing at low light, at
    8 or 12 mag it was half ok but not great.
    edi

  8. #8
    Quote Originally Posted by ejg View Post
    When set at 4 mag I couldn't see a thing at low light, at
    8 or 12 mag it was half ok but not great.
    edi
    low mag usually gives better light gathering in lower light than higher mag.

  9. #9
    what about the unknown effect windage it a greater variable
    Last edited by african jack; 01-09-2012 at 22:06.

  10. #10
    Quote Originally Posted by bewsher500 View Post
    low mag usually gives better light gathering in lower light than higher mag.
    That is right, but to the eye on a ffp scope the crosshair line gets finer with lower mag. That's why this is not really a low light reticle.
    Think it's called varmint 8. You can imagine a line that is 0.14" thick at 100yd only magnified by 4 is hardly visible in day light.
    At 16 the line is well visible but as you say light gathering.
    If you like I can post you the S&B PDF that explains it better.
    edi

    African Jack,
    plenty practice at longer ranges will sort that.
    At least you'll learn when not to shoot due to wind.
    Stalkers head into the wind, little effect. ha ha
    Anyway I don't think Hales is talking of much more than 300m
    edi

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