Load development help!

[Goobie270]

So I've been doing some load developing with a 5r milspec 308, hornady 178 hpbt, lapua Palma brass, imr 4064, and small gold metal match primers.

First groups were shot at a coal of 2.830. All loads from 40 to 44 grains were around 5-6 inch groups at 385.

Second test groups were shot exactly the same except a coal of 2.805. All groups were 5-6 inches until

43.4


43.7


44.0


So my question is now should I play more with seating depth?, or what could one do to tighten up the 43.7 group. The 43.7 group measures 2.1 inches.

 

[Homerange]

So my question is now should I play more with seating depth?, or what could one do to tighten up the 43.7 group. The 43.7 group measures 2.1 inches.

Go up a tenth and down a tenth in case the node improves more.
From here on be sure to work with fully fire formed brass.

 

[Goobie270]

Go up a tenth and down a tenth in case the node improves more.
From here on be sure to work with fully fire formed brass.

Ok I will try 43.6, 43.7, 43.8., at 2.805.

 

[Dusty Stevens]

I always liked the large primer with the heavier bullets/powder

 

[Ledd Slinger]

Ok I will try 43.6, 43.7, 43.8., at 2.805.

If you can't find a node that with good accuracy that will span across .3gr charge weights, I don't think there's a good reason to test in .1gr increments. Even if one of those charge weights gives good accuracy, it may be an unforgiving and volatile load. Finding accuracy between groups with a .3gr spread is not much of a 'node'.

Can you give us a rundown of the rifle and scope?

Definitely play with seating depth. Not sure where your seating is at now or if you are limited by a magazine length from touching the lands, but try to start by testing with touching the lands, then move in for a .005" jam and back out to a .005" and .010" jump.

Might also try some Remington 7-1/2 or CCI BR4 primers. Primers can have a huge effect on accuracy, good or bad. If you are getting good group shapes, meaning no 'fliers', but not quite the accuracy, sometimes a primer change can dial it all right in. Worth a try anyhow.

 

[Ned Ludd]

I've never seen an accuracy node in .308 Win that spans a 0.9 gr charge weight window in my entire life. Not even close. It is far more typical to see node widths of around 0.3 to 0.4 gr total, so testing in 0.1 to 0.2 gr increments is most definitely advisable once the coarse charge weight region has been identified.

 

[Ledd Slinger]

I suppose if the 44.7 group stayed good from 44.5 to 44.9 that would be pretty good. Anything is worth a try. Should be able to dial in a node by playing with seating depth and testing around the 44.7gr.

One thing that concerns me with these groupings is the POI is different for windage and elevation on all of them. Looks loke they were shot on different days or the targets were in different loations. Was it windy? Did the scope shift or get adjusted? Is parralax fully eliminated? Or is this just the way the loads act? I would also definitely be running the loads over a chronograph. (Well, all load testing should be done over a chronograph) Speed variations can tell you a lot about whether a spot is worth tuning. Then the measuring of COAL. There is nothing consistent about that measurement in regards to seating depth.

So many unanswered variables. Hard to help so I'm just gonna butt out of this one. Good luck fellas.

 

[Goobie270]

Ok guys, it's a remington 5r milspec 308, with a nightforce 5.5-22-56. The longest coal lenght I can go due to magazine lengtt was 2.830 which was horrible all through charge weights. The loads were shot on the same day, no wind at all, no parallax at all.

Oh the 44.0 gr load was adjusted a little too far to the right, so they wouldn't have been that far appart.

 

[Delfuego]

Try this method out. It might really help you. Try .010 seating increments. I would also ditch hornady and get Sierra 175 matchkings. If you still got nothing, try different powders.

http://forum.accurateshooter.com/threads/here-is-my-tip-on-how-to-find-ideal-seating-depth.3933366/

 

[Goobie270]

Originally I was thinking of keeping everything the same and changing coal length trying

2.794up in 0.004 increments to 2.814 and see if it changes my grouping since 43.7 at 2.805 was my best group.

I'm not sure, I guess I have work to

 

[Dusty Stevens]

That milspec barrel is not going to shoot its best at mag length. The one i had shot 175smk very well but they were on the lands or maybe .010 off