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Discussion Starter #1
I have a steel swinging target that has held up well for 3 years. Last summer I put up a 4 gongs and I am having a hard time with the carriage bolts. The heads of the carriage bolts are shearing off when the target is hit. It happens from 100 yards with anything from 5.56/223 to 450bm. Usually they last 4-5 hits on the smaller calibers and 1-2 on the larger. When the heads are hit (on purpose) they are just fine so I know it is straight sheer forces. Maybe I got 3 bad batches from two different stores. Planning on buying grade 8 carriage bolts if the next batch doesn’t pan out. What is everyone using and how are they holding up?
 

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Come and Take Them!
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Increasing the mass (thickness) of the plates may reduce the stress on the bolts. Going to grade 8 could also be a solution. Are the plates free to swing??? If not, they should be.
 

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Discussion Starter #8
F89B9EDC-8DF3-47F3-8889-7FB9C768A564.jpeg

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Here are the photos. The target is layered like this. Bolt head, target, washer, chain, washer, lock washer, nut. Chain is swinging on a piece of rebar suspended on Shepard hooks.
 

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You might try some bumper bolts they're better steel than those carriage bolts you buy at Home Depot etc, if you have a NAPA parts store they can get the Bumper bolts ..
 

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Live Secret, Live Happy
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View attachment 296468

View attachment 296470

Here are the photos. The target is layered like this. Bolt head, target, washer, chain, washer, lock washer, nut. Chain is swinging on a piece of rebar suspended on Shepard hooks.
Carraige bolts are not intended for your application, and the fracture you are getting, indicates your bolts are cheap chinese junk.

Consider buying grade 5 bolts (std hex head) machine bolts, and touque them solid.
 

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Free-ish Man
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Just use regular grade 8 bolts. Grade 8 carriage bolts are hard to come by. I just tighten the nuts finger tight anyway so there's no real advantage to using carriage bolts.
 

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View attachment 296468

View attachment 296470

Here are the photos. The target is layered like this. Bolt head, target, washer, chain, washer, lock washer, nut. Chain is swinging on a piece of rebar suspended on Shepard hooks.
It's not a shear problem, you're exceeding the tensile strength of the bolt. The plate is absorbing the energy from the bullet and the distance from impact to the bolt is acting like a lever arm multiplying the force and popping the head off.

If this is the case the solution would be a looser connection so the plate movement isn't applying stress on the bolt. Could probably ditch the spring washers and leave 1/8" of play between the chain and target.
 

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"TURGID FLUX"
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Longer bolts with compression springs.

Sent from my SM-T350 using Tapatalk
 
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Hang Fast Targets
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Grade 8 bolts

Grade 8 bolts have high tensile strength which is exactly what is needed to keep the heads from shearing off.

Grade 8 Carriage bolts are hard to find but you can get them here:
 

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Start up the rotors
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I just use regular bolts with washers and they work just fine.
A metal washer and a rubber washer under would be one solution.
We tend to weld a direct connection, but have used simple hooks through the holes. Have to replace those occasionally too.
Part of the deal.
 
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