.22 bullet BC's ?
- Thread starter boxhitch
- Start date
- Location
- Western Manitoba
If you are typing into a ballistic app, you might be one notch out with the decimal point - I do not think many bullets have G1 ballistic co-efficient larger than 1.000, but apparently some do - just a guess on my part, but probably 0.172 or 0.155 is likely what you meant. Is possible that some Finns, or some Europeans, might ignore the decimal point altogether when they type out numbers. As per lapua.com website, Lapua makes centerfire cartridges in Finland, and rimfire cartridges in Germany.
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It's worth noting that published BC values -- Lapua's 0.172, for example, or those provided elsewhere -- are approximations and actual values may vary. Bullets within the same lot can have different BC values. Unlike jacketed centerfire bullets, .22LR bullets are soft and malleable, and they obturate as they pass through the leade and bore. It won't matter much when calculating trajectories up to 100 yards or so, but the potential for inaccurate calculations grows as distance grows longer.
turbo_bird
CGN Ultra frequent flyer
- Location
- Kamloops, BC
For CCI standard I'm using .1 RA4 BC in Strelok, and it's pretty close out to 200m or so. I did a bunch of playing with the multi BC settings in Strelok and managed to get it close out to maybe 300m. I switched to SK long range match ammo for PRS, and at the same time one of the local hotshot shooters suggested that I try the Lapua custom drag function for 22lr in Strelok, and it works great. All I ended up doing was adjusting my velocity to get the prediction to line up with my actual results. I haven't even chronographed the SK, just started with the advertised speed and that was close enough to get started. It gets me pretty damn close out to about 400m or so, so good enough for me. The only time I get a surprise as far as elevation goes, is when the wind is doing weird things like a tailwind going up a hillside lifting the bullet, or I forget to account for angle when shooting up or down a slope.
Kristian
Kristian
the question came up when looking at the Lapua site for info on their Long Range offering 421068 , thought the numbers looked high so wanted some comparisons
they claim improved wind performance, so I'm guessing they have some proven testing behind their numbers
they claim improved wind performance, so I'm guessing they have some proven testing behind their numbers
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I have an Infinity Sierra program and see readings from 0.109 to 0.140 (Eley Match).
When that 0.172 appeared it struck me as somewhat elevated as most other Lapua are considerably lower and wrote it off as Metric or Internet Enhancement.
When that 0.172 appeared it struck me as somewhat elevated as most other Lapua are considerably lower and wrote it off as Metric or Internet Enhancement.
True BC function is your friend. SK RM under G1 BC is .152 and SK LRM under RA4 is .116 for me out of the same rifle. Have never used the multi bc function. I verify at 50,100,200 & 300m. Been told the Lapua drag function works for SK but haven’t found the need to play with it yet.
turbo_bird
CGN Ultra frequent flyer
- Location
- Kamloops, BC
The only reason I tried the Lapua drag function was because I was starting with different ammo and no baseline, and it was suggested by a guy that is always above me in the standings. Haven't tried the SK LRM with a regular BC yet, and haven't had any reason to try anything else. There's more than one way to skin a cat it seems.
Kristian
