GTA
Target Shooting Matches, Discussion & Events => The Long Range Club => Topic started by: rsterne on February 24, 2017, 06:54:43 PM
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I thought you might be interested in a comparison between what we are doing in NUAH and shooting a .308 Winchester (7.62 NATO) round on the NRA 600 yard course, using the MR-1 target.... First of all, with the new proposed changes to the NUAH target, the target proportions are identical, in terms of MOA, to the MR-1 target.... Here are the dimensions....
(http://i378.photobucket.com/albums/oo221/rsterne/Targets/NUAH%20vs%20NRA_zps5znb3soy.jpg) (http://s378.photobucket.com/user/rsterne/media/Targets/NUAH%20vs%20NRA_zps5znb3soy.jpg.html)
In the chart below, I compared a RN .308 bullet to a .25 cal pellet, and a HPBT .308 bullet to a typical .25 cal airgun bullet.... using 600 yards to the target for the PB and 100 yards for the airgun.... I used 2700 fps for the .308 PB round, and 900 fps for the airgun as being typical velocities.... In both cases, I chose to zero the rifle at 1/3 of the distance to the target, as those ranges are pretty typical... I used a BC for the airgun that is 1/6th of the BC for the PB, again fairly typical.... In both cases, I assumed a 10 mph 90* crosswind all the way from shooter to target.... The drop and drift are in MOA, just like the targets are....
(http://i378.photobucket.com/albums/oo221/rsterne/Targets/NUAH%20vs%20308%20b_zps2jccm8wz.jpg) (http://s378.photobucket.com/user/rsterne/media/Targets/NUAH%20vs%20308%20b_zps2jccm8wz.jpg.html)
You can see that shooting an airgun at 100 yards is a lot like shooting a PB at 600 yards, in terms of the challenges involved.... In fact, individual differences between pellets or bullets is more significant than the difference between a centerfire rifle @ 600 and a typical airgun @ 100.... Some airgun bullets used in high performance Big Bores, have even higher BCs than I used in the above chart, so a fairer comparison would be to shoot those further away, such as at 200 yards.... At such distances, the drop becomes more of a concern, and the drift actually less (in MOA).... but of course you can compensate for the drop with your scope adjustment, or by using an elevated rail.... The fact remains, that for the airguns that most of us are using, shooting on the NUAH target at 100 yards is very similar in terms of challenges to shooting a .308 Win. (7.62 NATO) on the NRA MR-1 target at 600 yards.... Nice to know !!!
Bob
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You just gave the little kid in my head the biggest grin, thanks again Bob!
Blue
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Bob, may I assume if I reduce the NUAH target by 50% on my printer, and shoot that target at 50yrds it remains the same dimensions as if I was shooting the MR-1 target at 600?
Might be more realistic for those shooting .177.
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Bob, may I assume if I reduce the NUAH target by 50% on my printer, and shoot that target at 50yrds it remains the same dimensions as if I was shooting the MR-1 target at 600?
Might be more realistic for those shooting .177.
Bob's the man and I totally defer to his reply.
My thought would be that the dimensions would remain close but the drop/drift/deflection wouldn't be the same.
I remember reading an article years ago (and time is not always my memory's friend) where someone found that shooting a 14ish grain .22 pellet at somewhere in the mid 800 FPS range mimicked the drop and drift of a (I think) .308 at (here's where my memory really fall off) 500 yards (more?).
Fun to think about, more fun to not have to walk that far to change out targets (or find someplace that lets you stretch out that far).
Blue
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My Brother bought a new Tikka in .308 for last deer season, and while sighting it in I was able to shoot a 3 shot, 1/2" ctc group at 100yds with it, from a very warm barrel.
Pretty darn good for a hunting rifle! Would be fun to try it at 600yds.
Jim - jhm757
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Bob, may I assume if I reduce the NUAH target by 50% on my printer, and shoot that target at 50yrds it remains the same dimensions as if I was shooting the MR-1 target at 600?
Might be more realistic for those shooting .177.
There will be an ongoing 50yd match. sixshootertexan will be hosting a 50yd match again this year. Check out his .177 target here http://www.gatewaytoairguns.org/GTA/index.php?topic=117473.0 (http://www.gatewaytoairguns.org/GTA/index.php?topic=117473.0) . The 10 ring is only 1/2" which would be 1/2 the size of the NUAH target reduced by 50%. Come join in this coming season.
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Bob, may I assume if I reduce the NUAH target by 50% on my printer, and shoot that target at 50yrds it remains the same dimensions as if I was shooting the MR-1 target at 600?
Might be more realistic for those shooting .177.
There will be an ongoing 50yd match. sixshootertexan will be hosting a 50yd match again this year. Check out his .177 target here http://www.gatewaytoairguns.org/GTA/index.php?topic=117473.0 (http://www.gatewaytoairguns.org/GTA/index.php?topic=117473.0) . The 10 ring is only 1/2" which would be 1/2 the size of the NUAH target reduced by 50%. Come join in this coming season.
Yup! I'm impressed, great shooting.
Jim - jhm757
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Well we eliminate the drop by sighting in our guns at the target, the only relevant part of that comparison is how much MOA adjustment you need to reach the target from what might be a "normal" sighting in range for the rifle in question.... Drift isn't linear with distance, when measured in inches, but when you measure in MOA, it's not that far off, especially when you are reducing the distance.... so within reason, then yes, shooting at a half size target at half the distance is still pretty close.... However, this is the NUAH Club, so I don't think we would ever consider doing that.... If you look at my post about using the inside of the ring, and the advantage that gives to smaller calibers, you may have your answer....
Bob
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Wow! Really puts the challenge into perspective. I'm curious to see how all this shooting I am doing with my air rifles transfers over to my powder burners. Funny, I haven't touched mine since I got my air rifles.