Help with 139gr Scenar load

[hitman44]

Started to develop a new laod for my 6.5x55 using the 139gr Scenar. After not being able to get my nads on any N555 to try, I used the N165 I had on hand. I used the load date from Viht as the competent list was close to mine. Started with 5 charges and 3 shot groups:

The next day I chose 3 loads at 5 shots to try again either based on group size or chrono data. The 50gr group ALMOST pulled off a repeat performance, but sadly, the 5th shot was a deal breaker. I also noticed something when looking at the groups from both days. Ont the first day the POI were all relatively the same with each load. The 2nd day, each load seemed to creep down as the charge increased, which makes sense but why didnt it do that on day 1? The distance was 100 yards.

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My plan for today is re shoot the the 50gr and 48.5 load. If either repeat, I'll probably call it good. Thoughts, suggestions or advice?

 

[hitman44]

Well I dont know what happened today.

I shot this group first,48.5gr:

Then the 50gr which has been pretty much a .5 or better performer so far. To add further insult, the chrono data on the 50gr loads are about as good as it gets for me(although about 25fps higher than previous days)

Not sure where to look, my first thought was the scope but Im currently using a 5-25 NF ATACR in a Spuhr mount. I havent changed anything in regards to the loading process, temps/wind etc have all been consistent. I havent touched the scope since the first day in which I moved it about 1in left, no elevation adjustments have been made. Yet if you look at the groups over the last few days you'll see them creeping down.

In particular, the 5th shot from the 50gr group fired yesterday that dropped low has the same POI of where the first group started grouping today.

 

[TheOfficeT-Rex]

Not sure where to look, my first thought was the scope but Im currently using a 5-25 NF ATACR in a Spuhr mount.

Start with mount and ring torques.

...Just googled blazer r93 - The scope mounts to the barrel, on a quick change barrel system? I'd take a hard look at the barrel mounting in addition to the scope mounts.

 

[RldrNewby]

The velocity data in the last pic was excellent. I’m thinkin same thing in checking torque on everything from rifle to optics, possibly a good barrel cleanin too it it’s got a lot of rounds down the tube. Fire a few rounds to foul barrel, then run a scope tracking test with a known good load. If all is good with the optics tracking test, back to load development & re-evaluate.

 

[hitman44]

Was indeed the scope ring screws. This scope was waiting for for another rifle to be completed and I forgot I left the screws loose to adjust eye relief.