Standard GC design Boolits with Alu. or Copper gas checks.
I have read that once the Boolit leaves the barrel its' job is done .
I have also read that many have retrieved boolits with the GC still attached and they seem to feel this is a very good sign.
I have read that many feel that accuracy was improved just by adding GCs.
It would seem to me that if the GC comes off in flight that it could cause a disturbance which could effect accuracy.
I admit that I have only been using gas checks for a very short period of time and only on 55 gr. .225 dia Boolits in a AR15 M4 1:7 twist . I powder coat but till use gas checks as I have no desire to lead up the barrel and until I get a Chrony I really have no idea how fast my H 335 19 gr. load is. I know it runs on the dirty side which may mean that it needs bumping up.