Lordgunner

More than anything it really depends on the gun and the breech plug.

I use W209's for most of my shooting from a Knight, but I have shot a lot of Win T7 primers also and they work just fine.

BH is a hard to ignite powder, Western knows this also and to help reduce complaints they naturally recommend the hottest primers like the Fed 209A or the CCI-209M.

I would also say if there is any doubt in your mind - shoot the hotter primer.

I would not exclude your ML primers in this warmer weather - but you are going to need to do some load and primer development anyway.

Make sure that you compress your load - push the sabot/bullet combination down snugly on the powder.

One thing that you might find the hotter the primer the quicker the flash channel in your breech plug might clog up.

Good luck...