Thanks for posting the data!
You are a bit under the recommended starting loads for these projectiles and A7 as published by Accurate. You may see better cycling if you bump up the charge a bit - or, as you said, go with a lighter recoil spring. The starting loads from Accurate for A7 are:
180 gr plated: 9.9 @ 1041
155 gr plated: 11.2 @ 1173
135 gr NOS JHP: 12.2 @ 1299
The FTEs do not surprise me since you are running pretty light, but I'm curious about the FTFs. High primers? Light primer strikes? I did not notice what type of primer you are working with.
The Shadow is right that if you want to slow down these 10mm loads, faster buring powders may be more effective and tighten up those velocity spreads.
Last edited by Taterhead; 04-26-2010 at 00:57..