Specs Trued and nitrided 700 action with one piece PTG bolt (also nitrided) Bedded in an HS precision stock 27" 5C Broughton Barrel with SSG brake, also nitrided All velocities were from a Magnetospeed. OK, about a week ago I loaded up cases from 94 gr to 103 gr of RL33 pushing 230 Hybrids along with work up loads for my other 2 rifles, 6-284 and 6.5 WSM. Went out to the range and worked up all the way to 103 gr. At 103 gr I had a slight bolt lift (no ejector mark) with an MV of 3192. The 102 load show no signs of pressure and MV was 3162. Ambient temp was about 23*. Today I decide to do some temp regression testing with my 3 newest rifles, the 300 RUM being one of them. The plan is to load here at the house and shoot out the back window down into a wooded ravine using a big cottonwood as a backstop. Temp inside is about 75*. I accomplish the shooting with the 6-284 and 6.5 WSM without any hitches. 4 shots each with the loads I identified as max from last weeks shooting. Velocities were a little higher but no pressure signs except one slightly stiff bolt out of 4 shots from the 6.5 WSM. Then I chamber a 230 Hybrid with 102 gr of RL33 and fire. Very heavy bolt and blown primer, MV 3215. Very surprised at this. I go to the bench and load one with 101 gr. Chamber and fire. Heavy bolt lift and powder ring around the primer and big shiny ejector mark, MV 3219. Go back to the bench and load one with 100 gr. Same exact signs as the 101 load, MV 3160. Back to the bench and load one with 99 gr. Almost the same signs as 100 but slightly easier bolt, still heavy though, MV 3186. I decide to give the bore a quick scrubbing. So I give it a few passes with nylon brush and BTE. Then run half a dozen wet patches through it until powder and copper is gone. Then patch it dry. I load up another 99 gr round and this time, very easy bolt lift and no signs of pressure, MV 3101... hmmmm... so I load one with 100 gr and boom, back to heavy bolt, powder ring around the primer and big shiny ejector mark, MV 3207. I go back down to 99 and boom, all the bad signs and MV 3192. Then I go to down to 98, and boom, all the bad signs, MV 3164. Then I try another quick cleaning and load up 98 again. This time i still get the bad signs, MV 3148. Bolt lift isn't real heavy but it's a bit heavy with ejector mark and powder ring. So I load 97 gr and still get pressure signs with an MV 3121. That's it.... I throw in the towel Something is not right here fellas and if you can help me figure it it out I would be very grateful. And yes, I did check the accuracy of the scale (Chrgemaster) against my 10-10. It was right on.