order of BS for accuracy

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  • Last Post 31 August 2018
GWarden posted this 30 August 2018

Been lots of discussion on BS for accuracy. One question that comes to mind is the order that one tries all the things Joe listed that might affect accuracy. What made me bring this up is that yesterday  at the range I was working on CB loads for a Rem. 700V in 6mm Rem, 9" twist. Without going into long detail something that made a big difference early in the load development was bullet seating depth. I normally have the best accuracy with larger  cal. by seating the bullet out to where the rifling engraves the bullet.  I was doing this with the 6mm  (2.802" oal )and my agg. for three five shot groups at 100yds was2.23", nothing to get excited about. I remember Jim Carmichael had a article on cast bullets in the 6mm, best accuracy was not with the method I had been using. I shot three more five shot groups with the overall  length at 2.771". Aggregate of these loads was .865". For this particular rifle this made a dramatic difference in group size. Now I can start checking one at a time factors that do or don't affect accuracy.

Bob

Iowa

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frnkeore posted this 30 August 2018

Tell us more, Bob.

I have a 660 Rem in 6mm.

Frank

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Shopdog posted this 30 August 2018

What mould?

I have an old "V" in 6mm and shoot the RCBS 95g. It's been one of the easiest rigs to get consistent groups with.The barrel had <500 jb's="" down="" it="" when="" going="" lead.="" jb's="" down="" it="" when="" going="">

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GWarden posted this 30 August 2018

Here is some more info. The article I mentioned was in "The Art of Bullet Casting from Handloader 1966-1981". If anyone is interested send me your email and I  will send a PDF file of the article. What I did in going from having the bullet engraved by the rifling, and reducing the OAL, I ended up with the bullet having a .030 jump; that sure seems long, but the article mentioned deeper seating improved accuracy, I can speak that it does. I was using the RCBS 95gr bullet. I have tried all different mixes of lead and lino and what shoots the very best in all my rifles with GC is a mix of 15# new lead, 25# mag shot and 2%tin. I am using WLR primers and 16.0 gr imr4198. That was my starting load. Now as I try each of the BS ideas, I will change one thing at a time to see if I can improve accuracy. I normally shoot 10shot groups. 

Bob

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frnkeore posted this 30 August 2018

I have that book, Bob

Please keep us informed in this thread with your progress.

Thank you,

Frank

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Ken Campbell Iowa posted this 30 August 2018

now that you mention it ... i had a cast load for my 222 that shot best when the bullet was seated deep into the case.  had to jump about a half inch before it hit rifling ...   factory chamber, not tight neck ...

keeps us cast shooters humble .... very humble ...

ken 

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OU812 posted this 31 August 2018

I think seating bullets too long and relying on bolt closing can sometimes hurt accuracy. Especially if neck tension varies...bullet seating depth will vary.

 Lately I have been seating my 30 caliber bullets longer (but shorter), only .030" longer. Thinking this will help with more consistent chamber pressure when fired.

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