Components

[Magicsmokerr2@gmail.]

I've been reloading for years & had to replace everything after a fire. I have photos of a few of my data logs from years before. When re-creating one load in particular I used different primers because I haven't found CCI large rifle benchrest primers. I used the same everything else, clearly different lot #'s, otherwise. My group is not even close to what I had previously accomplished. My question is, does anybody feel that different primers could be the culprit? Could it be different lot #'s of powder? New equipment? All of the above?

 

[stringnut]

You have a huge amount of variables. There also is not a lot of info here. What cartridge, how far, what were the groups before, what are the groups now etc, is all pertinent info.

Primers can make some difference sometimes. In my experience it has not been huge. However have not ever experimented with this much. Only time I have changed primers is when what I was using wasn’t available. My accuracy requirements may be far different than yours. As such what I consider inconsequential may be huge to you.

If their is a huge difference I would suspect equipment . Reloading equipment manufacturers all turn out great stuff, but, everyone has a bad piece slide thru at times. I have seen one bad set of dies between all the people I know that reload and myself. The bullet could be seen to be crooked.

 

[Mk-211]

Has anything changed on the rifle?

Scope rings tight?

Action screws tight, torqued down correctly?

 

[GeoDudeFlorida]

You have a huge amount of variables. There also is not a lot of info here. What cartridge, how far, what were the groups before, what are the groups now etc, is all pertinent info.

Primers can make some difference sometimes. In my experience it has not been huge. However have not ever experimented with this much. Only time I have changed primers is when what I was using wasn’t available. My accuracy requirements may be far different than yours. As such what I consider inconsequential may be huge to you.

If their is a huge difference I would suspect equipment . Reloading equipment manufacturers all turn out great stuff, but, everyone has a bad piece slide thru at times. I have seen one bad set of dies between all the people I know that reload and myself. The bullet could be seen to be crooked.

Agreed. We need more info. Primers seem least likely to make as big an impact on group size as powder lot; powder lot will make about the same impact as bullet lot and case type/manufacturer. So, “All of the above,” but to greater and lesser degrees.

Really depends on what your standards are and what you’re shooting. All we know is it’s a cartridge that takes a Large Rifle primer. That don’t exactly narrow it down much.

 

[AJC1]

Your load was in tune for the current conditions using the run of components you had. When anything changes the tune changes. Use any data you had like velosity to retune your load. If your specs on ammo are good deep clean the rifle, check for tightness and try again. I've worked with two guys in the last month, one with loose action screws and the second guy was missing the rear screw on a new to him rifle.

 

[Walkalong]

I haven't found CCI large rifle benchrest primers

It's possible, primers can make a difference in precision rifle reloading at times, sometimes not, but as folks have pointed out, you changed everything.

Might have to start from scratch.