Accuracy variables in reloading ?

[1armoured]

I wonder at times what is /are the most important of the variables contributable by us, our components and our tools.
i.e. that which would contribute most to a bad group.


In the first instance, the components come to mind, and the gear used;
brass
projectile
primer
powder
press, dies


then if you think a bit further, we fiddle with seating depth, powder charge, etc
and even with neck reaming, case length, case weight variance, bullet weight variance, concentricity etc


Some of it I would say is 'standard' reloading procedure,
i.e.
good, consistent components
optimal seating depth
and powder charge


and then there is the brass,
quite a lot of potential for variance here, in;
weight
length
neck material thickness
primer pocket
flash hole
headspacing on neck or rim


I don't neck ream or check for concentricity, I rely on the quality of what I'm using.
I'm happy with my procedures for brass preparation and loading.


Today, I was looking at an old box of PMC .222 that I have reloaded a few times, but I can't remember how successful the loads were.
Bought as bulk 'surplus' some time ago in 55grSP factory.
I noticed that half the flash holes were off centre ?
Made me stop and think how much that would have contributed to a bad group or two ?
Bottom row mostly;
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cheers,
SS

[Reverend Recoil]

I will try to answer your question from a service rifle perspective.  I shoot a CMP AR15 service rifle.  It looks like a standard M16-A2 but is internally tricked out to hold all the shots in the X-ring at 200, 300, and 600yd.  This rifle is fired with an aperature sight and unsupported with a leather sling.  With this rifle I have aquired my NRA Master clasification.  On really good days I shoot High Master scores.
Components:  If you want consistant match grade accuracy, shoot those expensive match bullets.  For 200 and 300yd I seat the bullets to magazine length.  This is required for the rapid fire stages of the match.  I get plenty of X's if I do my part.  For 600yd I seat 80 or 82gr bullets 0.015" from the end of the chamber throat.  I use a RCBS Uniflow powder measure to meter powder for my 200 and 300yd loads.  I use a trickler and RCBS beam scale to charge powder for my 600yd loads.  Brass - I trim to length once during the life of the case.  Mixed brands of brass will still shoot well at 200yd.  This past year I have been using Lake City brass at 200 and 300yd and Lapua at 600yd.  I get a few more X's with the Lapua brass.  There are many good primers and powders.  Find out who is shooting well the type of load you are looking for and ask them what they are using.  Press - I use old cast iron RCBS, Lyman and Redding presses.  Dies - Forester benchrest dies are better than some and as good as any.  Redding are also good dies.
I do nothing else to the case other than trim to length once when new.  Anything else is a waste of time.  I do no load development.  Black Hills mass-produced factory match ammo will shoot championship scores.  It is not hard to make ammo just as good.  The time and expense of load development is better spent in the practice of marksmanship.  Good luck.

[Grumulkin]

The most important things I've found in regard to accuracy:


1.  Some guns like some bullets better than others and it's not always a match bullet they like.


2.  Some powders work best in certain cartridges with certain bullet weights.


3.  Occasionally primers make a difference but not often.


4.  As long as it's the same head stamp and unless you're a serious target shooter, brass brand doesn't make much of a difference.


5.  Primer pocket cleaning and uniforming and flash hole deburring will not make enough of a difference to notice.


6.  It is almost always a waste of time to trim and resize new brass unless you are a serious and competent target shooter.