Can I go shorter??

[phil384]

Ok thanks, I'll keep reducing it.

[bullbarrel]

Chap on here I know had a best group with 120 thou jump.

But to save reloads, as mentioned about, I'd start going back in 20s.

Doesn't sound like it groups well at all. Have you tried cleaning it

[phil384]

Yep, cleaned between each string.

So what do you suggest for the next 5 batches?

2.672
2.652
2.632
2.612
2.592

???

[roughshooter]

Wotcher Phil

been running the light fodder (87, 84 ,70 gn. bullets at 2.66 "- 2.67 " - no complaints, under 1 inch.

Browning A Bolt, IMR4064 or Vit. 140.

HTH
Col

[phil384]

Wotcher Phil

been running the light fodder (87, 84 ,70 gn. bullets at 2.66 "- 2.67 " - no complaints, under 1 inch.

Browning A Bolt, IMR4064 or Vit. 140.

HTH
Col

Different rifles obviously but unless I hear a big NOOOOOOO! I'll carry on with my next lot of batches from 2.592 up to 2.672 in 20 thou jumps.

Thanks

[kennyc]

what COAL does your reloading manual say for that bullet? failing that load to the same length as a similar factory round and then play with your powder charge until you are happy with the grouping, you can then mess with the COAL if you wish to see if it tightens the group.
Viht data gives 2.638" for COAL

[phil384]

I thought powder charge affects the velocity and COAL affects the accuracy?

[Parabuteo]

what COAL does your reloading manual say for that bullet? failing that load to the same length as a similar factory round and then play with your powder charge until you are happy with the grouping, you can then mess with the COAL if you wish to see if it tightens the group.
Viht data gives 2.638" for COAL

Exactly what Kenneth says.

SAMMI specs etc are arrived at for a reason and its a good starting point.

After spending ages messing about to get my old M67 to group with the rounds just off the landes I realized that it was an old rifle and would as likely prefer not to be overly stressed so I wondered how I could change things for the better.

Many years ago Russel Simmonds told me that often a long jump could be just as good as seating into the landes, but people just dont try it....unless they use factory ammo. Recently I developed a load that I am happy with that bunged all 5 rounds under a small orange NRA marker at 200, so its within 1MOA and fine for an oldie.

I loaded back to the standard mag length for .308 and used the manufacturers data for the powder involved (RS52) and happy days, the only thing I did differently was to factory crimp the neck with a lee factory crimp die.

I first found this to improve the accuracy with my 5.56 Ammo, so I tried it with my .303....same result. Seems to work well with .308 as well so worth considering for rifles where you are stuck with magazines. These dies cost peanuts for what they actually achieve.

Lee claim it helps "Iron out" neck tension issues and allows a more uniform pressure spike. Talking to someone who knows much more about internal ballistics than me (Bradders of Bradley arms) he pointed out that a lot of theory is belted about but most of us dont know "Exactly" what is going on in there regarding compressed loads, ambient temp etc, so sensible testing si the way forward.

Certainly for the type of shooting I do now I will not be worrying about neck turning, bullet pointing, bullet weighing etc, and COALs stay pretty well as advertised or as copied from service ammo.

I only really mess with the powder these days, life is too short when shooting multi positional to burn barrels out testing when one gust of wind can have you pointing at the next target.

That said a little 18" AR15 can produce surprising results if you shoot it right.