Thread: 7mm Rem Mag Troubles

Righteo. Pls help.

So I've been having a bit of fun/frustration recently reloading for my 7mm Rem Mag Browning X-Bolt. I've been running the 162g ELD-X with AR2217, 20 thou off lands.

First attempt (new brass):

Did a pressure test - one round each charge, increasing half grain each time til quite far over max (up to 74.0g) because wishful thinking. Managed to get up to that point with no sticky bolt - only some faint ejector stamps. Good (and expected) velocities.

Second attempt (once fired brass):

72.5g - light ejector stamp, no heavy bolt lift - average group (just over 1")
73.0g - heavy bolt lift and heavy stamp. Also much higher velocities experienced than in attempt 1. Tried two rounds to make sure it wasn't a rogue load - exactly the same result and the two shots were touching... classic.

Third attempt (twice fired brass):

70.5g - average group, higher than expected velocity - no pressure signs
71.0g - average group, higher than expected velocity - no pressure signs
71.5g - two shots touching and one flier (probably me), roughly expected velocity - no pressure signs
72.0g - three shots 0.5" group, expected velocity - no pressure signs

Fourth attempt (twice fired brass):

71.5g - 2" group, higher than expected velocity - the odd faint ejector stamp
72.0g - heavy bolt lift, heavy stamp, higher than expected velocity
71.5g - heavy bolt lift, heavy stamp, higher than expected velocity (went back to this load just because I was at a bit confused)

There seems to be a pattern here but I haven't worked out what's going on. I'm new to reloading but I also load for my 7mm08 and have found a couple of good loads for that rifle with no issues. I know my rem mag can shoot, as I've had reasonably good loads for it in the past. I have not tried these loads out recently but that would be a sensible next step. I suspect, though, whatever is causing this pressure issue is also causing the grouping to go wonky.

Any advice is very welcome. My suspicions are something to do with cleaning (have heard mention of carbon ring on other threads), possibly funky primers but I'm not sure why that would cause an incremental decrease in pressure threshold, or something completely new to me.

Cheers,
Elliott