180 grain Scirocco II\'s & .300 Winchester Magnum - Perplexed
I posted this on the a/r site, so if you have already seen it I apologize for the duplication.
Here is the background:
A few years ago (2002 to be exact) I spent a lot of time working up a load with the original version of the Swift Scirocco in the 180 grain guise. Result was a load that would consistently shoot sub-m.o.a., with the average of all the 3 shot groups I recorded being .886".
A year later Nosler comes out with the Accubond and not being able to leave things well enough alone I play with those until I get a good load. I hunt with that for three years.
Next, Swift comes out with the Scirocco II. I still can't leave things well enough alone so I think, wow, they improved it...I liked it before, I will give it a try. On top of that, I get a call from Bill Hober and visit with him for about 35 minutes one day and he convinces me to try them again. Wallah! I buy a box of them and load them up just like my load of old thinking they would shoot the same as the old. Afterall, the advertising from swift says "Now, with the introduction of the NEXT GENERATION…Scirocco II, the bar goes up again. Scirocco II has exactly the same profile, both inside and out. All load data and bullet specifications remain the same as the original."
I think I made a mistake with the assumption listed above here because I went to the range Saturday and fired a total of 13 shots (1 fouler and 4 three shot groups). The total group size of the 4 three shot groups was in the neighborhood of 3.5". None of the groups was under an inch, with the closest being about 1.5" (there were two of those).
In addition to this problem, I had sticky bolt extraction after the shots. Not sticky, bolt lift, just stiff pulling it back.
Anyway, after coming home p*$$&% and having time to think through it (probably too much) I have the following thoughts.
1. Everything can't be the same...they changed something in the metallugy to make it perform different.
2. Whatever they did increased pressures in my load to the point of the hesitant bolt throw/pull.
3. Change in pressure/velocity has messed with my grouping.
My thoughts are to back off in 1/2 grain increments for three different loads and see what happens from there.
What are your thoughts, opinions and advice based on the above description of events?