have recently acquired my new toy in the shape of a Tac.20.

i am using 32gn v max on 25gns of n130, 24gns of n130 pushed the v max up to 3950fps,

so at a guess the 25gn load would be pushing just over 4000fps,

can anybody tell me what the drop off would be on 200, 300,400 and 500yds?

appreciate any help, thanks.

Try here.

Hornaday

My .20 Tactical has a working load that chrono's 4,175ish. That's a safe load in mine with cases that have been loaded with it 7 or 8 times and still have tight primer pockets. Here's the data print for my load.

Load Data
~~~~~~~~~

Name: .20 Tactical @ 4,175
Ballistic Coeff: 0.210
Bullet Weight: 32
Velocity: 4175
Target Distance: 250
Scope Height: 1.500
Temperature: 70
Altitude: 4800

Ballistic Data
~~~~~~~~~~~~~~~
Range Elevation Velocity Energy ETA Drop Max Y 10mph Wind Deflect
0 yds -1.50 in 4175 fps 1238 fpe 0.000 sec 0.00 in -1.50 in 0.00 in
25 yds -0.64 in 4051 fps 1166 fpe 0.018 sec 0.06 in -0.58 in 0.05 in
50 yds 0.08 in 3930 fps 1097 fpe 0.037 sec 0.26 in -0.53 in 0.19 in
75 yds 0.67 in 3813 fps 1033 fpe 0.056 sec 0.60 in -0.45 in 0.44 in
100 yds 1.10 in 3699 fps 972 fpe 0.076 sec 1.08 in -0.32 in 0.80 in
125 yds 1.38 in 3588 fps 914 fpe 0.097 sec 1.73 in -0.14 in 1.26 in
150 yds 1.48 in 3480 fps 860 fpe 0.118 sec 2.54 in 0.08 in 1.83 in
175 yds 1.41 in 3374 fps 809 fpe 0.140 sec 3.53 in 0.35 in 2.51 in
200 yds 1.15 in 3272 fps 760 fpe 0.163 sec 4.71 in 0.69 in 3.33 in
225 yds 0.68 in 3171 fps 715 fpe 0.186 sec 6.10 in 1.08 in 4.28 in
250 yds 0.00 in 3073 fps 671 fpe 0.210 sec 7.71 in 1.54 in 5.34 in
275 yds -0.91 in 2978 fps 630 fpe 0.235 sec 9.53 in 2.08 in 6.54 in
300 yds -2.05 in 2884 fps 591 fpe 0.260 sec 11.60 in 2.69 in 7.86 in
325 yds -3.47 in 2793 fps 554 fpe 0.287 sec 13.94 in 3.40 in 9.36 in
350 yds -5.18 in 2703 fps 519 fpe 0.314 sec 16.56 in 4.19 in 11.02 in
375 yds -7.17 in 2615 fps 486 fpe 0.342 sec 19.48 in 5.10 in 12.83 in
400 yds -9.47 in 2529 fps 454 fpe 0.371 sec 22.70 in 6.11 in 14.79 in
425 yds -12.11 in 2444 fps 424 fpe 0.402 sec 26.26 in 7.23 in 16.92 in
450 yds -15.11 in 2361 fps 396 fpe 0.433 sec 30.18 in 8.50 in 19.23 in
475 yds -18.53 in 2280 fps 369 fpe 0.465 sec 34.52 in 9.91 in 21.78 in
500 yds -22.39 in 2200 fps 344 fpe 0.499 sec 39.30 in 11.49 in 24.54 in

"CAUTION"!!
There seems to be a large variance between one rifle to the next with the .20 Tactical as to obtainable velocities. This load is safe in my rifle using IMI brass but a lot of rifles wouldn't get close to that and I've seen some faster as well.
What the heck, why be lazy? I ran your data using 70 degrees F at 1500ft elevation arbitrarily. Here it is.

Load Data
~~~~~~~~~

Name: .20 Tactical @ 4,000fps @ 1500ft elevation
Ballistic Coeff: 0.210
Bullet Weight: 32
Velocity: 4000
Target Distance: 250
Scope Height: 1.500
Temperature: 70
Altitude: 1500

Ballistic Data
~~~~~~~~~~~~~~~
Range Elevation Velocity Energy ETA Drop Max Y 10mph Wind Deflect
0 yds -1.50 in 4000 fps 1137 fpe 0.000 sec 0.00 in -1.50 in 0.00 in
25 yds -0.55 in 3865 fps 1062 fpe 0.019 sec 0.07 in -0.58 in 0.05 in
50 yds 0.25 in 3735 fps 991 fpe 0.039 sec 0.28 in -0.53 in 0.23 in
75 yds 0.89 in 3609 fps 925 fpe 0.059 sec 0.66 in -0.43 in 0.53 in
100 yds 1.37 in 3486 fps 864 fpe 0.080 sec 1.19 in -0.29 in 0.95 in
125 yds 1.67 in 3367 fps 806 fpe 0.102 sec 1.91 in -0.09 in 1.49 in
150 yds 1.77 in 3252 fps 751 fpe 0.125 sec 2.82 in 0.16 in 2.19 in
175 yds 1.67 in 3139 fps 700 fpe 0.148 sec 3.93 in 0.47 in 3.03 in
200 yds 1.36 in 3030 fps 652 fpe 0.173 sec 5.26 in 0.85 in 4.01 in
225 yds 0.81 in 2923 fps 607 fpe 0.198 sec 6.83 in 1.30 in 5.13 in
250 yds 0.00 in 2819 fps 564 fpe 0.224 sec 8.65 in 1.84 in 6.43 in
275 yds -1.09 in 2717 fps 524 fpe 0.251 sec 10.75 in 2.47 in 7.91 in
300 yds -2.47 in 2617 fps 487 fpe 0.279 sec 13.15 in 3.19 in 9.57 in
325 yds -4.15 in 2520 fps 451 fpe 0.309 sec 15.85 in 4.03 in 11.40 in
350 yds -6.17 in 2425 fps 418 fpe 0.339 sec 18.88 in 4.98 in 13.42 in
375 yds -8.58 in 2331 fps 386 fpe 0.370 sec 22.30 in 6.06 in 15.67 in
400 yds -11.40 in 2240 fps 357 fpe 0.403 sec 26.14 in 7.30 in 18.17 in
425 yds -14.67 in 2151 fps 329 fpe 0.438 sec 30.42 in 8.70 in 20.91 in
450 yds -18.39 in 2064 fps 303 fpe 0.473 sec 35.15 in 10.28 in 23.86 in
475 yds -22.62 in 1979 fps 278 fpe 0.510 sec 40.40 in 12.05 in 27.09 in
500 yds -27.33 in 1895 fps 255 fpe 0.548 sec 46.13 in 14.01 in 30.51 in
525 yds -32.78 in 1815 fps 234 fpe 0.589 sec 52.59 in 16.25 in 34.34 in
550 yds -38.96 in 1737 fps 214 fpe 0.632 sec 59.79 in 18.78 in 38.54 in
575 yds -45.91 in 1662 fps 196 fpe 0.676 sec 67.75 in 21.61 in 43.08 in
600 yds -53.62 in 1589 fps 179 fpe 0.722 sec 76.48 in 24.75 in 47.92 in

Hope that helps.

P.S.
I would personally consider N120 a fair bit too fast for the .20 Tactical and would at least slow it down to the H4198 or N133 range, preferably something between BenchMark to H4895ish. Quite likely that would provide more consistency in your loads. I'd be cautious however of real fine ball powders especially like H335 as they are quite temperature sensitive. Just a thought.

thanks montdoug,

i will get out and have a tinker with it.