 |  | | | |  |  |  |  | Anybody know the BC of HN Field Target in .22? |  | |  |  |  |
Posted: Fri Apr 29, 2011 10:28 pm |
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| domer_pyle |
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| Even though the Polys whomp, they have a worse BC than Premier domes in .22 despite being heavier and appearing to be more aerodynamic. Pretty much set on keeping with the HN but I'm curious about what Chairgun will tell me. Thanks |
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Posted: Fri Apr 29, 2011 10:37 pm |
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| rsterne |
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I measured the BC of H&N FT's at 0.021.... and the Silhouette at 0.016.... The Silhouette looks the same but has a ridge around the outside of the head and weighs ~16 gr. instead of ~14.5 gr....
Bob |
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_________________ Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal: Too many to count! |
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Posted: Fri Apr 29, 2011 11:52 pm |
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| domer_pyle |
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| Thanks for the quick response. I'm just a little confused, you mean the FTT are .021 and the FT are only .016? What are a few other BCs you've measured with other pellets? Just to compare, I think when I looked it said the FTT were somewhere around .03 unless that was the wrong pellet. It would be nice to see results people have gotten with some popular pellets and compare to what is in the program |
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Posted: Sat Apr 30, 2011 3:14 am |
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| domer_pyle |
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| Found the link to the BC and weight chart Chairgun provides, sure enough the FTT is .029 Premier domes (Accupel) are .026. Wish I could say more but I'm at work and on my phone right now |
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Posted: Sat Apr 30, 2011 11:48 am |
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| rsterne |
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I dug a little deeper into my data and found that the first BCs I quoted you were done with a 26 FPE PCP (numbers in red & bold below) .... The Beeman FTS is the same pellet as the H&N Field Target Trophy.... The Beeman Ram Jet is the same as the H&N Field Target (with the ridge around the edge of the head).... BC varies a LOT depending on the velocity, and not in a linear fashion.... it has a "peak" and falls off both at low and high speeds.... In addition, the barrel (particularly if choked?) has an effect.... here are some measurements I have done over 25 yards at different velocities:
Beeman FTS / H&N Field Target Trophy
492 fps - 0.020
665 fps - 0.029
690 fps - 0.026
888 fps - 0.021
Beeman Ram Jet / H&N Field Target
474 fps - 0.014
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664 fps - 0.018
859 fps - 0.016
JSB Predator
470 fps - 0.017
623 fps - 0.025
649 fps - 0.020
854 fps - 0.024
JSB Exact (Numbers in Red all with the same PCP at different power settings)
476 fps - 0.020
612 fps - 0.040
650 fps - 0.028
611 fps - 0.030
749 fps - 0.037
862 fps - 0.031
955 fps - 0.024
1024 fps - 0.020
The numbers in black & bold were done with a B-26 Springer.... and the ones immediately below them (just a few fps higher) were done with a Phantom Springer.... Although the velocity is very close, the B-26 produces a much higher BC for whatever reason (and I wouldn't use those numbers as they don't compare to most other guns).... clearly demonstrating what a difference barrels can make.... I tested the JSB Exact series extensively in my adjustable PCP and you can see what happens to the BC with velocity.... It peaks at ~750 fps and falls off drastically after 860 fps....
Bob |
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_________________ Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal: Too many to count! |
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Posted: Sat Apr 30, 2011 1:04 pm |
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| domer_pyle |
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| Veeerrrry interesting. I knew the BC changed a bit with speed, that's why I wanted to compare your numbers to CG's but I didn't know there was a curve and sweet spot to the change. At the speeds Preds are doing to get .024 I think I'll actually stick with them and use the HN FT to practice (same exact POI in my rifle). Those Polys really smack critters into submission |
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Posted: Sat Apr 30, 2011 6:41 pm |
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| packrat |
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| Which of those 2 pellets are the most accurate??? |
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_________________ HEY !! This getting old thing is NOT for sissies... |
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Posted: Tue May 03, 2011 6:46 am |
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| domer_pyle |
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| packrat wrote: |
| Which of those 2 pellets are the most accurate??? |
Guess you'll have to get some and see for yourself! Out of my XL they're both stacking on top of each other at 25 yards though |
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Posted: Wed May 04, 2011 7:19 am |
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| packrat |
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| I asked the question because it is pertinent to making the correct decision..if one was more accurate than the other...your "oh so wise" remark was totally unwarranted IMO..... |
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_________________ HEY !! This getting old thing is NOT for sissies... |
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Posted: Wed May 04, 2011 2:59 pm |
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| domer_pyle |
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| Do you need a hug? I didn't know anyone around here couldn't handle a little joke. Guess next time I'll make it more apparent I'm being a smartass |
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Posted: Fri Jun 10, 2011 3:18 am |
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| DavidS |
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| domer_pyle wrote: |
| Veeerrrry interesting. I knew the BC changed a bit with speed, that's why I wanted to compare your numbers to CG's but I didn't know there was a curve and sweet spot to the change. At the speeds Preds are doing to get .024 I think I'll actually stick with them and use the HN FT to practice (same exact POI in my rifle). Those Polys really smack critters into submission |
Say Domer,
When you said those Polys really smack critters into submissions I figured I pass this bit of info along that I discovered the other day.
Three errant shots, scope got out of alignment, hit a fairly heavy gauge Aluminum shed along side the target stand. I was shooting from a distance of 35 yards/105 ft away and the Benjamin NP no sooner let go when I heard the pelltets hit. The first two were RWS Super Points and punched right through the skin like it wasn't there. The third shot hit a stiffening channel on the side that extended out about 3/4" and was about 1.25" wide. Again the Crosman Hunter pellet with a semi-point being slightly rounded, weighed in at 7.5 grn [I just wighed 6 of them on my RCBS Electronic Powder scale] made an entrance hole of .208" but made an exit hole the .311" dia which I say is really quite amazing for such a little projectile.
Now, I don't know the speed it was traveling at but I'd have to say it was quite significant to cause an impact like that. |
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_________________ I'm a Firm Believer in Gun Control!
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