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PostPosted: Mon Jun 28, 2010 3:49 pm 
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Joined: Sat Nov 03, 2007 4:19 pm
Posts: 8935
Location: Coalmont BC
I asked for a link to the Kill Zone sizes and this was given for the CAFTA guidelines (many thanks for that):

I was curious about how much aiming tolerance was allowed to be able to get a clean kill at the maximum range selected for each KZ size so I did some calculations.... I made three assumptions....

1. That the rifle is .177 calibre and that for a clean kill the edge of the pellet must clear the edge of the kill zone.... I realize that if just the edge of the pellet is shaved off, the target will probably still fall.... depending on the pellet energy, shape and hardness.... but I have no way of assessing those variables....

2. That the rifle being shot was just capable of shooting consistent dime sized OD groups from a solid bench rest at 50 yards with no wind.... This means that the C-T-C distance of the worst shots is 0.5" across at 50 yards.... plus 0.18" for the pellet gives a group of 0.68" OD.... In most circles, that would be considered a pretty darned accurate rifle....

3. That the shooting position is not "forced" so you can shoot from whatever position is the best for you.... If you are forced to shoot from kneeling or standing the KZs must be at least 1.5" and the distance a maximum of 45 yards.... so this chart will not apply....

Here is a table showing the OD of the group.... assuming a cone shaped C-T-C variation proportional to the range.... which I have found to be typical from the bench with no wind.... The note following the group size is how much your shot can be off compared with how you shoot from the bench and still drop the target....

55 yards: C-T-C size = 0.55" + 0.18" pellet diameter = 0.73" OD group.... 1.5" KZ allowed.... 0.38" aiming error OK
50 yards: C-T-C size = 0.50" + 0.18" pellet diameter = 0.68" OD group.... 1.25" KZ allowed.... 0.28" aiming error OK
45 yards: C-T-C size = 0.45" + 0.18" pellet diameter = 0.63" OD group.... 1.0" KZ allowed.... 0.18" aiming error OK
35 yards: C-T-C size = 0.35" + 0.18" pellet diameter = 0.53" OD group.... 0.75" KZ allowed.... 0.11" aiming error OK
25 yards: C-T-C size = 0.25" + 0.18" pellet diameter = 0.43" OD group.... 0.5" KZ allowed.... 0.03" aiming error OK
20 yards: C-T-C size = 0.20" + 0.18" pellet diameter = 0.38" OD group.... 0.375" KZ allowed.... NO room for aiming error
15 yards: C-T-C size = 0.15" + 0.18" pellet diameter = 0.33 OD group.... 0.25" KZ allowed.... You do the math!.... NO room for aiming error even at 10 yards

Now before I get jumped on my the CAFTA Board.... Let me clarify that these are the MAXIMUM distances for the KZ sizes in the chart.... I would imagine that a significant number of targets are placed closer than that.... This post is NOT to be construed as a critiism of FT in any way.... It is only meant to let people be aware of just how difficult this sport CAN be if the targets are used at their maximum allowable ranges....

Have a look at the above chart.... Then think about the variables of wind.... and how much you wobble around even in your best FT shooting position compared with shooting from a bench.... You can be darned proud of your FT scores.... particularly on those targets placed at or near the maximum allowed for that size KZ.... :mrgreen:


Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
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PostPosted: Mon Jun 28, 2010 5:18 pm 

Joined: Fri Aug 24, 2007 9:21 pm
Posts: 2102
Location: Greater Napanee, ON, Canada
Can't see why any of the FT guys would be upset at this. It is a pretty good illustration of how tough some of the shots in a match are. There are always those targets close to the maximum distance and they are the ones that usually ultimately determine the winners in the FT classes. A pretty good pucker factor on a few of those, what.

Thanks Bob.


CAFTA Governor

PostPosted: Mon Jun 28, 2010 9:25 pm 

Joined: Sat Jul 14, 2007 11:45 am
Posts: 2099
Location: Southern Ontario
rsterne wrote:
It is only meant to let people be aware of just how difficult this sport CAN be if the targets are used at their maximum allowable ranges....
You don't have to remind any of us how tough FT is! Maximum allowable ranges or not, there are so many factors that contribute to a successful or unsuccessful match. To watch some of these guys consitantly put together nearly perfect matches is really incredible!

PostPosted: Tue Jul 06, 2010 8:02 pm 
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Joined: Fri Jun 26, 2009 7:42 am
Posts: 4080
Location: Somewhere In Time
....... :|

Great info Bob, I would be interested in seeing the PFT numbers as well.....Really puts things into perspective

"Are you guys silly? I'm still gonna send it..."

PostPosted: Sat Jul 24, 2010 3:42 pm 
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Tread has been cleaned up . :|

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PostPosted: Sat Jul 24, 2010 4:41 pm 
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Joined: Sun Oct 04, 2009 7:44 pm
Posts: 1279
Location: Longueuil
thank you under500fps it was geting out of hand

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