Enfield headspace issue?

[NC_Xplorer]

Hello everyone,
I shot my No.4 in a CMP vintage rifle match on Saturday and I was using new reloads that I had worked up using new brass. I experienced multiple cases with visible splits about .125 to .250 above the rim and at least 3 complete head separations. My Enfield is fitted with a #3 bolt head. From my research on this forum I have concluded that I have excessive headspace issues. Will this require a gunsmith to fix or is there another solution? I know from reading a copy of a manual that was posted here that I have the largest bolt head already. I don't think switching to a lower numbered bolt head will fix this. Has anyone else had a similar problem like this?