Canadian Airgun Forum

I thought you might like to see what I whipped up today from my scrap metal box.... It doesn't have the face plate fitted so that you can see the guts and how it works.... The steel face plate will be 3" tall and 7" wide, with two holes, of whatever size you wish up to 1.5", about 4 1/2" apart.... It will bolt on (with the two 1/4" bolts shown) so that you can have several, with different size holes....



The basis of the design is an over-center rocker arrangement, preloaded by a spring so that it sits either left or right....



The paddle holder is a 4" corner bracket from a hardware store, welded to a cut down 4" strap hinge.... all framing pieces are 1" x 1" x 1/8" angle.... The paddles are cut from 1/8" steel plate.... and the mount for the face plate is 1" x 2" x 1/4" plate, drilled and tapped 1/4-20 NC.... The front of the spring rides on an 3/4" long 8-32 bolt and the rear sits on a 2" long 1/4" bolt....



I found the target to be a bit fussy as to spring tension.... If you set it up so that it will flip at 4 FPE, when you shoot it with 12 FPE it will sometimes cycle completely (left-right-left) because it bounces.... I found that for my purposes, if I set it so that it works reliably at 6 FPE then it still works perfectly at 14 FPE (I haven't tried it with anything more powerful yet).... This could easily be solved by making an adjustable spring tensioner.... or by simply changing springs.... Two springs would probably cover most shooting situations....

The base can be either pegged to the ground through the three holes in the ends of the legs, or it could be bolted to a piece of plywood and then weighted down.... I think the functioning could be improved by attaching the paddles further out, so that the center of the holes (and paddles) were 2 1/2" to 3" from the pivot point.... I found that lightening the paddles (they were originally square), and striking them further out, both improved the functioning at lower energy levels.... less mass to accelerate from the pellet impact, and a longer lever arm for the force to act through....

I know that this target doesn't have the satisfaction of having the target fall down when hit.... but there is no string required to reset it either.... you just keep shooting, alternating from side to side....

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!

very nice, I have been working on a similar setup, I havent worked on it in a while but it shouldn't take much more to complete.








GT

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QB.30 PCP w/ Leapers Bug Buster 4x32AO Mil-Dot
QB78D .22 w/ Leapers 3-9x40AO Mil-Dot
QB78 .22 Custom HFT Stock w/ Leapers 3-9x40AO Mil-Dot
Crosman 1100
Crosman 2240
Custom 2050
Brass M2250
Tanfoglio 1911

Yours was the inspiration for mine....

I think the replaceable faceplate so that I can have ones with different holes is a good idea.... I wasn't sure if it was your intent to have holes you have to shoot through or just hit the paddles.... I also noticed that in yours the spring geometry is different on one side and the other.... have you noticed a difference in the energy required to flip it on the two sides?....

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!

Yes one side takes ~6fpe, the other takes ~8fpe, I still would like to change the spring setup, that was just thrown together quick.

As for the face plate, it's 3/16" I may do something later on but for now I will just clean up the edges.

GT

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QB.30 PCP w/ Leapers Bug Buster 4x32AO Mil-Dot
QB78D .22 w/ Leapers 3-9x40AO Mil-Dot
QB78 .22 Custom HFT Stock w/ Leapers 3-9x40AO Mil-Dot
Crosman 1100
Crosman 2240
Custom 2050
Brass M2250
Tanfoglio 1911

So it's your intention to just shoot at the discs?.... that's kinda what I thought.... and why I decided to make a faceplate with holes in it that will mount in front of the paddles.... so you have to shoot through the holes just like on a "real" FT target....

I didn't like the idea of being able to hit the arms for the paddles.... and I also wanted to be able to change target size easily.... I still have to pick up a piece of steel for the faceplate.... I was thinking that 1/8" would be fine.... can anyone tell me if I need to go to 3/16"....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!

no 1/8" should be plenty, I just used what I had on hand. eventually I might add a faceplate, but for now this will work.

GT

_________________
QB.30 PCP w/ Leapers Bug Buster 4x32AO Mil-Dot
QB78D .22 w/ Leapers 3-9x40AO Mil-Dot
QB78 .22 Custom HFT Stock w/ Leapers 3-9x40AO Mil-Dot
Crosman 1100
Crosman 2240
Custom 2050
Brass M2250
Tanfoglio 1911

I made some 1/8" faceplates today.... I couldn't get any 3/16" material.... lucky to even find anything in Princeton....

I made four plates, the one installed in the picture has 1" holes in it.... the other ones are 1 1/2", 3/4", and 1/2".... I also made a sliding adjuster for the spring tension (white slotted gizmo in the photo).... with an added benefit that by rotating it a bit from side to side you can also adjust it so that both paddles take the same energy to flip....



During testing, I found out that FPE is not the only thing that makes a difference.... Surprise, surprise, a .22 pellet will activate it reliably with significantly less energy than a .177 pellet.... It took only 4 FPE to make it flip reliably with a 14.3 gr. pellet, while it took 6 FPE to make it function properly with a 7.9 gr. pellet....

If you have ever used ChairGun2, you will notice that it will calculate the "Momentum" (the basis of the old Taylor "Knockdown Numbers" for hunting big game).... If I remember my Physics, Energy is Mass times Velocity squared, whereas Momentum is just Mass times Velocity.... The idea is that a heavier bullet (pellet) with the same energy will have more "knockdown power".... ie the old argument about why the RCMP carry a .45 not a .38, etc. etc.... It turns out a 14.3 gr. pellet at 4 FPE actually has MORE momentum than a 7.9 gr. pellet at 6 FPE....

In any case, in .22 cal, the target will function perfectly with only 4 FPE, and it will easily handle 14 FPE without bouncing (and I think a fair bit more).... I did confirm that hitting the paddle further out from the pivot does make it flip easier.... but with my adjustable spring tension I can now custom taylor it if I want to shoot a low powered .177 at the longer ranges....

I'm very pleased with the results and can't wait until the Spring when I can take it outside and use it at longer ranges.... BTW, could one of the FT gurus let me know what are the typical ranges for the four sizes I have? (0.5" 0.75", 1.0", and 1.5")....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!

Dude........I am having the same issue with my target.....177 at 7ftlb wont take it down but .22 will at about the same power

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Jonathan

Moderator

I'm really surprised our resident FT gurus haven't addressed the "Momentum" vs "FPE" issues I have raised on this thread.... I am convinced that if you set a target up to trip at 5 FPE with a 2289 (.22 cal) that it won't drop at 5 FPE from a 1377 (.177 cal) especially with light pellets....

I'm also still hoping someone will tell me the typical target ranges in FT for 0.5", 0.75", 1.0", and 1.5" KZs....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!

Well I brought it up on the DrFrankengun forum and it was explained to me that the targets are set at point blank range. I know nothing about ballistics,FPE,energy......ect.......so I let the experts explain it to me.

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Jonathan

Moderator

I do not consider myself a guru, but..

When I test the targets, I shoot them point blank with a pistol generating under 5 ft/lb of energy. If you do not shoot them point blank, the pellets lose energy fairly fast. I have shot them with .177 and .20 cal pellets with similar results. If the energy that hits the paddle is 5 ft/lb, it should go down if adjusted properly.

If you are using a 5 ft/lb gun and shooting them from a distance, you do not have 5 ft/lb hitting the paddle. For example, a gun shooting an 8.4 gr pellet at 500fps generates just over 4.6 ft/lb of energy at the muzzle. At 10 yd, it only has 4,2 ft/lb of energy, at 20 yards, 3.8 ft/lb.

A 14.3 gr pellet traveling at 382fps would have the same energy at the muzzle. The energy at 10 and 20 yards are extremely close to the values for the .177 pellet.

Is there a momentum consideration for different weight pellets? Perhaps so. Since I do all my FT shooting with .177 pellets, testing with .177 pellets is probably the best thing for me. The majority in the sport also use .177. If a .177 pellet with close to 5 ft/lb of energy will take a target down, then at ,20 or .22 at the same energy will definitely take it down.

Another consideration that is often overlooked is trajectory. It comes into play at longer ranges. No pellet hits the paddle a right angle. A slower moving pellet hits at a more severe downward angle changing some of its energy or momentum into a downward component, leaving less energy or momentum to push the paddle straight back. A 14.3 gr .22 pellet with 382 fps at the muzzle (4.6 ft/lb) is dropping at 1" per yard by the time it reaches 40 yards, 1.5" per yard at 50 yards and over 1.6" per yard at 55 yards. An 8,4 gr .177 pellet at 500 fps(4.6 ft/lb) is dropping .5" per yard at 40 yards. 75" per yard at 50 yards and .85" per yard at 55 yards. Although this does not seem like much, watching it through a scope as the pellet flies to the target really shows how fast that pellet is falling.

The mistake many make is trying to use a gun generating 5 ft/lb at the muzzle to take down targets at FT distances. You may be OK at 10-15 yards, but for anything beyond that a person would be lucky to take the target down.

For those of us setting targets up for matches, the problem is having a target that will fall reliably with a shot at or just under 5 ft/lb and not fall if hit on the face with a shot generating 18-20 ft/lb. One or the other is easy, but both needs some fine tuning.

Hope this helps some.

Tim

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Tim
CAFTA Governor and lifetime learner

HI Tim....

Thanks for your answer.... I do all my 5 FPE drop testing at point blank range (but I use about a foot, because I have found the air blast from the muzzle actually has some effect at an inch).... It is at that one foot range that I have found it takes about 6 FPE with a 7.9 gr. .177 pellet to have the same effect as 4 FPE with a 14.3 gr. .22 pellet.... and I am growing more and more convinced that this is due to the momentum difference....

I think it would be an excellent idea to specify that targets must fall when hit by a 7.9 gr. pellet at 5 FPE (ie 533 fps).... there would then be NO confusion about the sensitivity of the target.... and like you say, it would DEFINITELY fall with a 5 FPE hit from a larger caliber and/or heavier pellet....

Any information on the typical target distances for the KZ sizes I specified would be appreciated....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!

The CAFTA BOGovernors is in the process of creating SUGGESTED distances for the different size kill zones. We have been at matches where some targets were placed at distances that basically turned a hit into a lucky shot. We want to address this issue and once we come up with a chart, we will publish it on our website and also outline the highlights in posts on the various forums.

It could very well be resolved and public within a few weeks.

Tim

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Tim
CAFTA Governor and lifetime learner