ORIGINAL: elmer deer
I was doing some load development in my 7mm mag using RL22 and 160 accubonds, I checked a few books and started at 65grs and went past max at 67grs. So my velocity at 65gr was 2843 5 shot average, 65.5 gr shot up to 2990av. could not figure out why? Any Suggestions? Next 66gr back down to 2886 av. and my group shrank to.250" shots, great!Then went a touch over max to 66.5grs and speed was 2933 and it opened up some, next went up to 67grs and my group for 3 shots went into .153" excellent again but the other 2 shots opened a bit, my error I think. I see that most everyone pushes their speed to 3050 alot of times,is it safe for me to go a little higher like to 68 grs of RL22? Have not seen any pressure signs like sticky bolt.My barrel is also 26 inches long and the gun is a Sauer202, What are your experiences with the first situation of a jump of velocity? And is velocity a safe way to gauge if your getting near max? Because book velocity does not match my numbers.
Thank you
Elmer
Your 65-66gr velocity gain seems reasonable. I am not a big advocate for people trying to build loads in such fine grandularity. REally with magnum loads, its not going to be consistent. I only see one set of velocities out of whack and thats your 65.5gr set. Rest seem reasonable. I believe you are expected way too much expecting 3050 for a 160gr bullet.
I personally know 3 people who are trying to obtain nosler's numbers for this combo, and all are little shocked they are not.
Nothing out of the ordinary not to meet the numbers.
Look for the classic pressure signs. Primers, hard bolt lift, etc. A chrony number is just another piece of data for you to make your decision on max load. use it for what its worth. If you see your velocity shoot up like incredible numbers, your gettin in dangerous territory.