At a monthly police PPC & Bullseye match some years ago an officer was shooting in the bullseye match and using very mild WC loads. He fired 6 rounds with no damage to the heavy barrel Mod 15. A local machinist/gunsmith removed all 6 and put the gun back in service. The officer didn't notice the problem until he went down to check his target after the last stage of rapid fire. He must have left one in the barrel on his previous stage and stacked the last 5 behind it.
That is a problem shooting mild hand loads that barely recoil. With normal power loads a squib will be instantly noticed, but with super-mild target loads, a squib can easily go with little notice.
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