Hi Jack ! I had a similar question recently on .223 rem. You'll find chamber dimension variances for different mfgs. including the Wylde by going to: r/l standard cartridges page # 15 and look for my post " .223 rem. SAAMI specs needed". If you know the mfg. of your present hd space gauge you can compare it to Wylde specs. & add a shim or tape to the base of your .223 gauge to match the Wylde specs. ( Wylde chamber will be longer) Chk. the specs for the base to shoulder length. If you have a cartridge hd space gauge for .223 rem. you can also measure your present gauge and compare to the Wylde specs & add scotch tape accordingly to base of your gauge. Hope this helps, Dale Forgot to mention the shoulder angle on all .223's will be the same except .223 AI.