Primers why in the hell!!!..help

davide montini

davide montini

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Ok I’ve been beating my head against the wall with a rifle I bought .....
Fnh fnar ..7.62x51 semi auto .....1:12 twist 20 “ heavy barrel
So I tried for almost 6 months...not every day but on weekends when time permits different combinations I tried the 155’s...168’s..
Imr 3031 ..varget ..h4895...imr 4895.....then primers...cci #34 ...Winchester large rifle .......
So for what I tried mmmmm 1” groups ..so so ......it can do better
But the one day I jumped to the 175gr nosler cc ....with benchmark and federal 210 primers ...not 210m....
And Jesus h Christ @ 100 yards I print a 1/2 inch group!!!!!!!...
What in God’s name makes a gun go from ####ty to a magically printing 1/2 “ groups 651B0103-4E6C-47B8-8FAC-EF9DC7372AF8.jpg
 

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Sometimes your gun just likes a certain combo of primers, powders, powder weight, brass, COL, bullet and bullet weight. Happens all the time to me.
 
I was at the point that I emailed fn and told them ...they replied if you getting 1”groups you doing good!
They also told me that that particular rifle was designed around the 168gr bullit???and the 175...
Holy Hanna I fired over hmm...I’d say over 500 rnds trying this and trying that .....
For the love of god I reload for other calibres mostly hunting rifles .....and I usually nail it in less than 100 rounds or more
I’ll tell you the grief I had from this rifle ....I was at the point of selling it
But not any more !
 
Maybe you accidentally discovered a load that causes the bullet to exit the muzzle at the top (or bottom) of a sine wave node point where the flexing barrel has a moment of near motionless hang time before changing direction. Rather than some where else along the the sine wave path where the muzzle is in constant rapid motion when the bullet exits the muzzle.
 
The primer is the last thing to be concerned with.

If every other step in the reloading process is looked after, cases weigh and volume sorted, powder charge 0/+ .02 gns, neck tension exact from one to the next, overall cartridge length exact one to the next, concentricty of the loaded round displays zero run out, powder charge >95% of case fill, a powder where all the deterrent chemicals are consumed at max pressure, and on a vibration node.

THEN if you are getting and extreme spread in velocity > than 10-15 ft/s it would be prudent to try different primers check velocity and adjust powder charge back to the node.

This assumes your rifle/scope are mechanically sound.
 
A rifle will often have a strong preference for a particular bullet. You may have found it.

Is this group repeatable? a single 5 shot group does not mean much. The fliers could have gone into the group instead of out.

Let's see a couple 10 shot groups. If they are under an inch, you have a load. Then stock up on more of the bullets of the same lot number.
 
davide montini said:
Ok I’ve been beating my head against the wall with a rifle I bought .....
Fnh fnar ..7.62x51 semi auto .....1:12 twist 20 “ heavy barrel
So I tried for almost 6 months...not every day but on weekends when time permits different combinations I tried the 155’s...168’s..
Imr 3031 ..varget ..h4895...imr 4895.....then primers...cci #34 ...Winchester large rifle .......
So for what I tried mmmmm 1” groups ..so so ......it can do better
But the one day I jumped to the 175gr nosler cc ....with benchmark and federal 210 primers ...not 210m....
And Jesus h Christ @ 100 yards I print a 1/2 inch group!!!!!!!...
What in God’s name makes a gun go from ####ty to a magically printing 1/2 “ groups View attachment 193548
Click to expand...
 
One 5 round group doesn't mean much. Try 5x5, see what that looks like. 5x 5 round groups on 5 identical targets. Don't adjust your scope between groups, have a defined point of aim on each target. When you're done, stack your 5 targets on top of each other, you'll effectively have a 25 round group, then you'll see what's really going on. Software like OnTarget TDS is great for doing this.
 
did you try different brands of 168 and 155 and other 175's? my one rifle shoots hornady 168's really, really well but doesn't do as well for the 168 SMK which for a lot of people seem to be the end all of bullets or in 308/30 cal atleast.
 
Hmm ok thank you to all...for all the advise ....very kind of you all .....I didn’t see things on the same angle ....but now I’ll try some ideas out to re-verify
Once again thank you to all of you
 
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