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Post by oversteer on Aug 24, 2021 3:14:03 GMT -8
Hello
I have a 4K Pro mounted on a T1X 22LR shooting Eley Subsonic hollows 1040fps 38gr 0.115 BC and CCI Subsonic 1050fps 40gr 0.12 BC, before the latest firmware upgrade the ballistic calc worked OK, gun in sighted in at 50m and I range/shoot between 25 and 95m mostly, BC put POI very close using bullet GL.
After latest firmware upgrade which basically wiped the scope so I had to start completely from scratch(I screwed up and didn't save profiles to SD card...would have been nice for the upgrade tutorial video, which was quiet involved, to have mentioned to save your profiles at the start...).
So now while sighting in rifle, using the variables above(which I used before) puts the POI way high at 90m, like 5-6 inches !
So I played around with the ballistic calc and put in 0.2 bc and its very very close, just a touch high at 90m.
What's happening here !? 0.2 is way different in terms of BC to the published and tested figures for the ELEY and CCI ammo, is changing the BC the best thing to do ?
I wasted a LOT of pricey ammo getting an acceptable sight in with this scope, the rabbits also don't like getting wounded and the foxes are laughing at me and learning too much !
Cheers
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tciii
Contributor
Posts: 46
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Post by tciii on Aug 24, 2021 17:16:24 GMT -8
It's quite common to adjust the BC and FPS to dial it in.
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Post by oversteer on Aug 24, 2021 21:56:35 GMT -8
Ok thanks good to know.
My concern here is what the ballistic calc is going to do with fudged numbers at ranges outside what I have actually shot targets at like 100m+ and in-between 50-100, not that I actually use the distance input currently outside 50 and 90(just guess hold over and do alright) but I have a the laser rangefinder on the way which will set things exact.
More testing required I guess ! would help if I was using a flatter caliber, but this is all he law allows here, where I shoot there's a lot of livestock and buildings etc so I'm just trying to be careful, need high percentage shots to catch the round in the varmint, rocky ground see's a lot of ricochet's, even sometimes after going through varmint.
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pattism
Member
Not what I fathom, but the Truth
Posts: 17
ATN Products Owned: Smart HD Optics, Night Vision Optics
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Post by pattism on Aug 25, 2021 5:33:23 GMT -8
I use several 22LR with my scope (mostly <2000 fps), with and without suppressor. Each one I've zeroe'd without issues around 40-50 yards. I find that most 22LR, between 1050→1080 fps, has an ideal range around 40 yards. Meaning that 40 yards, a ±10 yard movement will only have ~1/8" drop (pretty flat). But at 100 yards with that same ±10 yard movement, could have ~2.5" rise or drop (5.0" variance); That's enough to completely miss or inhumanely injure; So for me, 75+ yards just isn't an accurate enough range for the rounds I used. In my case, my rifle likes the CCI SV, which using a chronometer, it measures around 1065→1075 fps. At the range on a bench, I shoot about 1/3 MOA with it at 40 yards. Then with using the ballistic calculator and ranging at 100 yards, I get ~1.5 MOA on target. My last thought... It's one thing for bench shooting, where things are not moving and you're ideally not forgetting to re-range distances, set temperature, elevation & pressure. It's something different in the field where you might not re-range or notice a 10 yard change in things.
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Post by oversteer on Aug 25, 2021 18:31:06 GMT -8
Yeah I hear what your saying, I can chart the bullet drop on my target 50-90m and its a far bit, 5-6 inches between those ranges, but also going down from 50-30 there's 2 or so inches iirc, I have a friend that shoots semi professionally for land owners(rabbit fox cat dog) and he uses subsonic rounds too for accuracy, once dialed with quality rounds they are very consistently accurate. Restricting the 22lr 1050fps round to under 40m I think is a bit short plus the rabbits and foxes learn ! hard to get that close round here.
Would love to step up to 17HMR, but its just too loud to keep the peace with the horsey people round here, if you know what I mean !
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