200 ft lbs is a little disappointing

[Kabic]

CCI Blazer 158 LRN .38 Special has a muzzle energy of 200 ft lbs.

I was using that to test my homebrew resetting knock down target (version 1). I was afraid it would not stand up to the beating. What I found was that it would only knock it down with springs disconnected and hitting high on the target.





Here are the reasons I think it failed my expectations

1) Too much slop in the system eating energy. 1/2 conduit would not go though the 1/2 tee so I used 3/4 ... that is a loose fit. Also the landscape timber might be moving in the concrete block. I tried to wedge a 2X4 in there as well, but can do better I think.

2) I might need to lower the pivot point so it turns easier.

3) maybe just too heavy

I have some ideas for version 2 that should be simpler.

 

[Waveski]

I noticed the pivot point right away , and WOW - that's a lot of spring. Looks like it would take 30-30 to overcome.
When we shoot steel plate at our local club the targets are leaning just forward of TDC , no springs. Even then , a low hit with 9mm at 15 yards sometimes fails to knock down.
Looks like you did a real good build , but overkill. Better off hanging the steel from chains.

 

[Kabic]

I think I will also test this first version as a rifle target, 223 at 100 yards should be close to 1000 foot pounds ( I think)

 

[TonyAngel]

At the place where I shot indoor steel, when they were "calibrating" the plates, the would hit them with a 9mm to see if they would fall. A plain ole .38 would't do it. It apparently takes a lot to over come the inertia of those steel target plates. If spring tension would hold it up, maybe mount it so that it is leaning a little backwards so that not so much of the weight of the plate needs to be over come.

 

[Kabic]

I noticed the pivot point right away , and WOW - that's a lot of spring. Looks like it would take 30-30 to overcome.
When we shoot steel plate at our local club the targets are leaning just forward of TDC , no springs. Even then , a low hit with 9mm at 15 yards sometimes fails to knock down.
Looks like you did a real good build , but overkill. Better off hanging the steel from chains.

I think you are probably right on the springs, but they do stretch pretty easy by hand. I do have other targets that I hang with chains, just trying something different with this one.

 

[Waveski]

Given the mass of your build you may have a real nice rifle target.
I shot on private property that had a spring loaded steel target ; the round target disc was even on a 4" pedestal; the darn thing only wiggled with 9mm or .38 sp. 30-30 slapped it down pretty well , but I wondered how high and far the cartwheeling bullet went when it left the steel. Handgun bullets sometimes came back to the shooter. Bullets seemed to deflect downward and die much better with targets on chains , except for .22 which did not disturb the target sufficiently. Lots of small pieces came back , but with minimal velocity. Real good case for safety eye gear.

 

[Walkalong]

Over built, I like it, suffer from it, but in this case.......

 

[jmorris]

What I found was that it would only knock it down with springs disconnected and hitting high on the target.

Look where your pivot is, if you hit it at that point or below, the only way it’s going to fall is if the stand is flexible enough to move back and forth underneath the target making it fall.

I built my plate racks (all 3/8” plate) so even a .22 LR would drop the plates several hundred yards away, by putting the pivot well below the plate itself.



The button is only on the last plate, to reset them all. The “C” shaped piece of metal is so the barstock cannot bottom out the button, rather just depress it enough to close contacts.

 

[Kabic]

Look where your pivot is, if you hit it at that point or below, the only way it’s going to fall is if the stand is flexible enough to move back and forth underneath the target making it fall.

I built my plate racks (all 3/8” plate) so even a .22 LR would drop the plates several hundred yards away, by putting the pivot well below the plate itself.

View attachment 895934

The button is only on the last plate, to reset them all. The “C” shaped piece of metal is so the barstock cannot bottom out the button, rather just depress it enough to close contacts.

I like it. Are you using an electric actuator to raise the plates?

 

[jmorris]

Automotive power window gear motors on the plate racks with further gear reduction. Two very high torque gear motors on the large plate under them.

 

[Jim Rau]

Why not just C-graph your loads and do the math??????

 

[Kabic]

Why not just C-graph your loads and do the math??????

That sounds interesting, can you elaborate?


For version 1, I used hardware that was available in store. For version 2 I just ordered hardware. Torsion springs from McMaster-Carr & some 90 degree Super Strut brackets from Home depot. Good price on the springs, but looks like McMaster-Carr charges you actual shipping cost and do NOT give you an estimate. Hopefully I wont regret that order, cost wise.

 

[Waveski]

Put the plate up on a shaft or pedestal like the one in #8. Leverage in your favor.

 

[Waveski]

jmorris -

Outstanding rig!

 

[MikeInOr]

It seems like that target would have a tendency to ricochet the bullet up into the air and off to who knows where?

 

[WestTexShooter]

CCI Blazer 158 LRN .38 Special has a muzzle energy of 200 ft lbs.

I was using that to test my homebrew resetting knock down target (version 1). I was afraid it would not stand up to the beating. What I found was that it would only knock it down with springs disconnected and hitting high on the target.

View attachment 895827
View attachment 895828
View attachment 895829

Here are the reasons I think it failed my expectations

1) Too much slop in the system eating energy. 1/2 conduit would not go though the 1/2 tee so I used 3/4 ... that is a loose fit. Also the landscape timber might be moving in the concrete block. I tried to wedge a 2X4 in there as well, but can do better I think.

2) I might need to lower the pivot point so it turns easier.

3) maybe just too heavy

I have some ideas for version 2 that should be simpler.

View attachment 895830

Sorry, but what is with all that Styrofoam looking stuff surrounding the target and on the ground?

Looks similar to what i saw in our freezer one day!

 

[Waveski]

If I may offer an answer to that —-
The words we use in reference to that stuff this late in the season would get me a warning from the forum moderators.

 

[Jim Rau]

That sounds interesting, can you elaborate?


For version 1, I used hardware that was available in store. For version 2 I just ordered hardware. Torsion springs from McMaster-Carr & some 90 degree Super Strut brackets from Home depot. Good price on the springs, but looks like McMaster-Carr charges you actual shipping cost and do NOT give you an estimate. Hopefully I wont regret that order, cost wise.[/QUOTE
High school physics.

 

[jmorris]

I like it. Are you using an electric actuator to raise the plates?

This is inside one of them and how it works. Took me a long time to come up with something that’s so simple, once you see it.



The other is a bit larger as the “gear” I used for the window motor is an old 168 tooth Chevy flex plate.

 

[Kabic]

Not all of the parts I ordered came in on my Home Depot order, but I am seeing what I can do with what I have.

Items ordered:

From home depot
super strut 2 hole 90 degree bracket (box of 10)
super strut 4 hole 90 degree bracket (qty 4) waiting on this still

McMaster-Carr 3 each of these two springs (shipping was $8 - $1.33 per spring)

Torsion Springs 120 degree deflection

OD                              0.871"                  1.102"
For Shaft Dia.                  0.625"                  0.666"
Wire Dia.                       0.095"                  0.135"
Leg Lg.                         3"                      4"
Number of Coils                 6.17                    7.17
Spring Lg. @ Max. Torque        0.713"                  1.102"
Max. Torque, in.-lbs.           15.75                   44.36
Material                        Music-Wire Steel        Music-Wire Steel
Pkg. Qty.                       1                       1
part number                     9271K908                9271K706
Pkg cost.                       2.47                    2.10

$3 of 1/2 inch hardware, sold by the pound at the local farm store chain.


The smaller spring (9271K908) is two weak to hold up the 8 inch plate...even two of them are not stong enough to return the plate upright. It might work with a 6 or 4 inch plate.

The larger one (9271k706) seems like it should work. Here are both springs pictured with 1/2 inch bolt.



I had to trim the corner on a pair of the 2 hole strut brackets to have room for the nuts on the carriage bolts to rotate around. The 4 hole strut brackets were ordered because I feared there would be some kind of clearance issue, too bad they are not showing up for a few more days.

A 6 inch long bolt 1/2 bolt ties it all together. If I had gotten a longer bolts, I could have put the timber side brackets on the outside and avoid having to trim the corner on them. I also added a piece of spindle I had left over as spacer for the spring to rest on, just cut a groove in it to retain spring leg.



I hope to test it tomorrow.

 

[Kabic]

2nd version was definitely an improvement. The 38 actually moved it ... 9mm markov about the same as the 38. 7.62x25 moved it pretty good as well.

I think i will try a slight revsion to lower the pivot and see how i like that.

 

[jmorris]

Any videos in action?

 

[Kabic]

Any videos in action?

I'll bust out the tripod and see what i can do.

 

[Kabic]

Disclaimers:
1. My pistol work can use some work.
2. The Combloc pistols do not shoot to point of aim with the ammo I have( Wolf & Prvi Partizan)
3. I cherry picked the video I took to try to make me look some what competent in shooting.
4. Could not find the camera I wanted to use, so I used the GoPro and I struggled a little to make it work.

The middle target is the target I lowered the pivot point on, but it had issues with some of brackets moving\twisting which blocked it from falling backwards. The target on the right is version 2 I posted above. Target on left is pretty similar to the one on the right, just taller base brackets and they are on the outside versus the inside.

38 Special:


9mm makarov


7.62X25

 

[jmorris]

Looks like the one hanging from the chain has good action.

I spent about 18 hours this weekend cleaning up in the shop and was about to go bonkers so I threw some of the stuff I had come across together and made a reactive target that works even for my old pellet pistol.