Nosler 105gr CC Leverevolution

[Bill]

Yesterday was my first reloading session for my Howa Mini Arc. I used some discontinued Nosler 105gr Custom comps with Leverevolution to get a good baseline as to whether Hornadys published data was credible.  I also put a fresh battery in the magnetospeed.

Thought it would be an interesting exercise to load up some ARC brass and test against some formed from Grendel brass.

I used Hornady reloading data as a guide and my speeds matched up well considering my barrels 22 inches

Hornady 6mm ARC brass, 1.49in, Rem 7.5, LVR

Charge       Velocity

29.7           2727  2750  2758  2727  2735
30.0           2776  2769  2776  2792  2771
30.3           2794  2795  2805  2813  2793
30.6           2817  2801  2811  2826  2807

Hornady 6.5 Grendel brass, 1.49, Rem 7.5, LVR

30.0           2810  2805  2817  2792  2826       6.5G brass produced an ave speed 33fps faster than ARC brass
30.6           2802  2825  2811  2847  2847

No pressure signs observed at all,  primers and cases look good.  

Best load was the ARC brass at 30.3gr,  groups size was 0.5moa

And I managed to find a little brass 

[StoneHendge]

Welcome aboard Bill - are you sure you didn't photoshop those bags of brass? Kidding aside, was either of the brass previously unfired? Fireforming virgin brass vs previously fired brass could give you a velocity difference like that.

[Bill]

No photoshop B-))

The 6.5G brass has had 6 or 7 firings and has been trimmed a fair bit. I also annealed the brass only 1 firing ago. I do wonder whether the higher speed was due to the greater neck tension. Ill be testing case capacity to get the answer.

All brass was originally from Hornady Black ammo for both chamberings

[grayfox]

My first guess would have been case capacity differing even if a slight bit...
But thanks for the data, any data to be posted is good, not too much as of yet to go around.
(I would have figured that your 22" barrel might have a node around the 2800 mark. Don't know if it's at half node or a node but ... well, them's my thoughts!!)

[Bill]

Yeah grayfox there appears to be a node around 2800 which Id be comfortable with, might have to seat the projectiles a little further out. Hoping too catch up with a few 6mm long range shooters shortly and grab a bunch of projectiles. Really like to gets some 103 ELD X's

[grayfox]

All mostly scarce as hen’s teeth. Think I saw some 105 rdf’s on ammoseek...
Not much else. 90 gr eldx’s.

[StoneHendge]

It would be interesting to see case weight along with capacity. All the manufacturers claim raw materials are hard to come by - especially copper. Wouldn't surprise me to see a little more (lighter and cheaper) zinc slipped into an alloy. Or maybe brass flows down as well as up when necking and bumping down. Are you using an expander ball? There is a measurable difference in neck brass thickness taking it from 6.5 to 6. It also magnifies inconsistencies.

GF, please pardon my ignorance, but what is a "half node"?

[grayfox]

Kind of a new term tome, although I’ve seen the concept. The shot’s longitudinal wave is a weird sine wave, so it has 2 spots where the muzzle tip is “quiet” each cycle. The grt app can calculate both the node and the 1/2 node as a place where your mv should be consistent, ie, you get an accurate round. The 1/2 node spot is not half-way between the 2 nodes however but you can calculate it... evidently. Some of my OBT spots that grt shows are like node 5 1/2. My own spreadsheet can only show me the obt node, but the grt can do the in-between ones.

[CZ527 Guy]

Looks like your data and Hornady data are very much in line. Your variables were a slightly different primer Fed 205 ve Rem 7.5's and a 2" shorter barrel.

Care to share more on your Howa barrel? I assume this is a custom barrel from the likes of Pacnor? Suppose I am interested in how many lands & what twist?

I am looking at having a cz 527 re-barreled to 6mm ARC in the next few months. Ordered the barrel close to a month ago.

Also interested in how smoothly the process went pushing the shoulder back on your Grendel brass?

[Bill]

CZ527 GUY I used a 5r Bartlein barrel.

I normally use BR4 primer but Ive been using the Rem 7.5 for the past year.

Got some 90gr lapua scenar coming this week too

[CZ527 Guy]

Bill: Looks like so far so good. Just breaking in the barrel? Or have you shot for groups with anything yet?