6.5X47 Velocity Nodes

[dblinden]

This is a new cartridge for me and a new barreled action had initial test today. Medium palma barrel at 32"; Barnard action; Berger 130 Hybrids; tested from bench though it is in a prone stock. 38 grns VV N150 with 450 primers yielded velocity at mid-2930's. With BR4 primers, yielded mid-2920's. Very low spread in velocities with each. Accuracy essentially the same.

Question - What are best velocity nodes others have obtained with this cartridge and any 130 grn bullet? Not highest velocity, but best velocity in respect to accuracy/group size.

Thanks - Dennis L

 

[Bart B.]

I don't think you have two velocity nodes. Many rifles will have a 100 fps spread in muzzle velocity for each of several bullet weights all producing equal accuracy with different charge weights. You may need to shoot a few dozen shots with each different charge across a 2-grain spreading the same right powder for each bullet to prove it.

 

[dblinden]

Thanks for responding Bart, but I am asking what velocity nodes others have obtained when using a 130 grn bullet. I was simply reporting what I obtained today.

 

[Bart B.]

What is a velocity node? How many shots per test do you use?

If you shoot the same load in 30 rifles with s few shot group, there will be 30 different sets of velocity numbers. Accuracy can be virtually equal across all.

Same rifle and ammo shot by 30 people with one few shot group, it will have 30 sets of velocity numbers but accuracy will have quite a spread across all 30.

 

[Patch700]

This is a new cartridge for me and a new barreled action had initial test today. Medium palma barrel at 32"; Barnard action; Berger 130 Hybrids; tested from bench though it is in a prone stock. 38 grns VV N150 with 450 primers yielded velocity at mid-2930's. With BR4 primers, yielded mid-2920's. Very low spread in velocities with each. Accuracy essentially the same.

Question - What are best velocity nodes others have obtained with this cartridge and any 130 grn bullet? Not highest velocity, but best velocity in respect to accuracy/group size.

Thanks - Dennis L

Speaking from my experience with this cartridge, you are probably at the top end rite now.. I would make a friendly bet with you that if you could safely get to 40grns of N-150 (I don't know your freebore etc) You may only get to 3000-3050fps.

I have had the best luck keeping 140 class bullets (Scenars) in an 8t at 2850-2875 and that is with 26" of pipe using N-550 , having said that it would be safe to say that this load on paper is fairly stout as compared to yours as you have 32" of pipe.

Obviously there are a bajillion other factors at play here but for long distance this has been a solid number for me.

I do also see a nice load with the above mentioned components at 2650-2700 but I opt for the top end node.

Nice combo you've got , good luck keep us posted on your findings.

 

[Forum Boss]

Bart B wrote: "You may need to shoot a few dozen shots with each different charge across a 2-grain spreading the same right powder for each bullet to prove it."

To each his own, but I think that is a complete waste of time and barrel life (if he means a dozen shots at many different charge weights). The OP is headed in the right direction. With a custom hand-lapped barrel with a length similar to others used in competition, it is a 100% good, valid procedure to ask around to see what velocities are working for other guys with good hand-loading skills and good barrels. In fact, when guys ask me about a new caliber/cartridge my first response is "chose a proven bullet/powder combination and ask around for the velocity nodes that seem to be working for others". In my 6mm BRDX I asked around for suggested loads by knowledgeable guys (including Sam Hall). Then loaded 8 rounds, two each 0.2 grains apart (in 0.8 spread) to measure/confirm velocity. Saw no pressure signs at the velocity I wanted. Then I shot a 3-shot group at that load to confirm my default seating depth preference for that bullet (Scenar 105) which it seemed to like (was lucky there). Then a serious 4-shot group at 100 yards over flags to confirm. It went into a 0.188. Load development done. Of course is it not always this easy! But targeting a known, accurate velocity node CAN save you time, money, and barrel life, so long as you're working with a good barrel, have enough barrel length, and have first-rate reloading skills.

 

[DHuffman]

Completely agree with Boss! Most of this has been done before a 1000 times by some pretty knowledgeable people and there's really no need to burn up components and barrel life!

 

[dblinden]

Boss said: To each his own, but I think that is a complete waste of time and barrel life (if he means a dozen shots at many different charge weights).

That, plus your other comments, is exactly where I am coming from so thanks. Not looking for controversy or even debate, just some info from people walking in places before me. This is a Bartlein 33" barrel that finished at 32". Why? Because I shoot iron sights from sling position and all my barrels have same sight radius. Don't want to use a tube extension and have found that this set-up optimizes my aim. I shoot 600 yds mid-range and 1000 long-range comps and this type of arrangement is not unusual.

To the original point, I am meticulous in my hand loading (measuring charges, pointing, etc), but do not want to spend a lot of time testing copious amounts of rounds. A BR friend helped with testing yesterday and was able to use his Labradar gear - really good! We essentially shoot at targets with a 1 mil X-ring for score which is generous, but just wanted to hone down some hence asking others for their experience. I have very minimal experience in testing ammo. I like Berger Hybrids which is why I selected the 130 to use. When I received my 6BR, I used 30 grns Varget and 105 Hybrids from day one and haven't changed anything. Similar story with my .308 Palma rifle.

For completeness, I shot 5 rounds at 37.5 cleaning after each shot. Then, five at 37.8 and five at 38.0 all with CCI 450's. Finally, five more with BR4's at 38.0. With the BR4's, the extreme spread was something ridiculous like 4 fps. Wider, but not terrible with the 450's. I had no intention of pushing anymore than 38.0 from the beginning.

Thanks for any help - Dennis L