First time doing load development, looking for advice and opinions

[jsel10]

First off, some needed info
Rifle: Sako A7 roughtech range 6.5 creedmoor
Range: 100 yards
Brass: New Hornady
Primer: CCI BR2
Bullet: Barnes 140 match burner
Powders: RL 17, IMR4451
Position: Prone with a bipod and rear bag

So as stated in the title, this is my first time doing load development for a rifle. My experience with reloading has been mainly pistol.
That being said. Some things that I noticed that struck me as being strange. My velocities seem very low. At max charge based off the Hornady manual I'm a full 100fps slower with a 26" barrel vs the 24" barrel used in there testing.
The next thing that I noticed was that the powders used performed in the exact opposite fashion of each other. RL17 got progressively worse with an increase in charge weight, whereas IMR4451 got progressively better. I was thinking it was possibly shooters fatigue that was causing the groups to open up. But it seems to consistent. I ran the entire string of RL17 first followed by the entire string of 4451. Should I have jumped back and forth between the 2? The best groups came from the 2 lowest charges of RL17, the velocity just seems way low. There were no pressure signs with any loads.Looking for advice on where to go from here? Possibly continue bumping the charge in .2 increments until I see pressure signs and maybe use a lead sled off a bench to eliminate as much human error as possible?

 

[jsel10]

These got cut off in the original post.

 

[Greg Langelius *]

First, jumping back and forth between different powders will confuse the carbon fouling component of the velocity result; so don't do that.

I am totally unfamiliar with the propellants in use.

It looks clearly as if 40.0gr of RL17 is a definite accuracy node. 39.5gr looks just about equally good. Splitting the difference may produce a more consistent node as temps vary. The 'flyer' is very likely to be shooter induced.

Looking overall, Verticality is a good indicator of accuracy, especially as a predictor of performance at greater distances. We want the bullets to all impact at the same height, with horizontal spread being somewhat discounted as a possible consequence of mid-trajectory crosswinds.

I think you have your load, 40.0gr of RL-17, but 39.5gr may turn out better if the development was being done at a lower than average temp. Try varying seating depths slightly, but I don't think significantly more accuracy improvement is likely or even desirable.

Velocities are going to vary gun to gun, bore diameter variances count a lot here. Known velocities (for me) are really only important to determine drops, and to ensure that the velocity on target exceeds 1300fps. Whatever they are is what they are, and as long as the round stays above transsonic, the big boxes are already checked in your load development. Wind calls will always be unique to a particular barrel and projectile, and you figure them out by shooting the distances enough to get to know them intimately.

Finally, ten shots do not a reliable node make. Shoot the node and one increment (for 6.5CM I would suggest a .3gr increment) above and below many times more, and make your final decision based on the statistical trends of the larger set of data points. Divide increments only if there's a nagging doubt involved.

Bear in mind that environmental differences, especially large temp swings, can throw a load out of tune.

Greg

 

[bullcityrising77]

I am currently in the same position as you: a new reloader evaluating RL-17 for a 6.5 CR (Tikka T3X TAC A1). Like you, my first good accuracy node was at a fairly low charge weight, and the velocities were not optimal. I found another node at 41.3 or so and another at 43.8 (at the expense of sticky bolt lift on 2 of 10 cases, so I abandoned that one). On all of the loads I have evaluated, my velocities have been substantially lower than those reported in the Hornday manual. However, it's been 60 degrees or less (sometimes a lot less) when I've been shooting this season, so that may have something to do with it.

I am going to head back to the range this weekend to evaluate incremental loads around the 41.3 mark to see if I can determine what works best, and will then start to evaluate seating depth and more consistent neck tension. I was getting fairly consistent 3/8-1/2 inch groups with that load, which is perfectly satisfactory to me. Velocity at 10-15 feet averaging 2672. When it comes available, I'd also like to try some H4350 since folks seem to think it is a solid performer with this round. Good luck!