Virgin brass

[juliomorris]

I have a savage 243 with a Shilen barrel. I have been working up loads for it so far i have 2 good posibilities. The thing I have noticed is that the loads that are in virgin brass seem to group better than the ones in the neck sized once fired brass. I have been loading in groups of 5 with 5 in new brass and 5 in once fired brass. I am using 105gr a max with 41,5 grs of IMR4350 they are pushing 3050 in the once fired and 2980 in the virgin brass. Any ideas? The other load is is 40 gr 4350 pushing a 105 gr berger.

 

[halfmoanut]

My guess would be that the neck tension of the virgin brass is less than when you neck size it after firing it and also the virgin brass is not completely formed precisely to your chamber as the once fired brass would be causing you to lose pressure which could inturn lead to lost velocity because of excaped gases around the neck and shoulder area of the virgin brass. Try using a bigger size bushing .001 up and see if your accuracy improves.Just my thoughts and by far an expert.

 

[queen_stick]

"The thing I have noticed is that the loads that are in virgin brass seem to group better than the ones in the neck sized once fired brass."

How bad is the accuracy? are the larger groups showing vertical?


Try reducing the load on the fired brass to match the velocity that you're getting on the virgin brass. Maybe you're right on the edge an 'accuracy node,' and the little extra velocity you're getting with the fired brass is bumping you out of that node? I have no idea if that's what's happening, but with everything else being the same, your velocity is the only variable that has changed.

Let us know if you figure this one out!

 

[juliomorris]

"Maybe you're right on the edge an 'accuracy node,' and the little extra velocity you're getting with the fired brass is bumping you out of that node?"

Thats what I have been thinking. They open up from about .375 to .625, so i was thinking that the increase in velocity was the problem. Thanks I'm going to back off on the load alittle and see. Thanks for the input guys.