Results N170 6.5 PRC

[Ironworker]

Loaded up some loads with N170 147gr ELD Nosler brass 28" Bartlein bbl 8"twist . 6 groups of 3 with Fed 215 Mag primer last group of 5 Fed 210 Match primer
48.5 AVG 2500
49,5 AVG 2520
50.5 AVG 2570
53,5 AVG 2750
54.5 AVG 2855
56.5 AVG 2959
Last 5 max load 57.5 Fed 210 match primer 1 2,964
2 2,975
3 2,972
4 2,998
5 2,952 AVG 2,972 SD 16.9
Now a little bit more data with N170 6.5 PRC in the cyber world

 

[Straightshooter1]

Loaded up some loads with N170 147gr ELD Nosler brass 28" Bartlein bbl 8"twist . 6 groups of 3 with Fed 215 Mag primer last group of 5 Fed 210 Match primer
48.5 AVG 2500
49,5 AVG 2520
50.5 AVG 2570
53,5 AVG 2750
54.5 AVG 2855
56.5 AVG 2959
Last 5 max load 57.5 Fed 210 match primer 1 2,964
2 2,975
3 2,972
4 2,998
5 2,952 AVG 2,972 SD 16.9
Now a little bit more data with N170 6.5 PRC in the cyber world

What COAL are you seating those 147 ELD's to?

 

[Ironworker]

What COAL are you seating those 147 ELS's to?

2.951 which fit the magazine ,I've since seated them to 2.920 so they comfortable fit the magazine

 

[Straightshooter1]

Hmmm??? Interesting. . . as I can't get my QuickLoad app to show those kinds of velocities, unless I increase the burn rate for the N170 by a little over 10% (at 70°F). A COAL of 2.951 is very close to 100% of fill with 56.5 grs. And with 57.5grs it's ~101.5% of fill with suggested pressure at 60k psi. I'm assuming a case volume pretty close to what my Lapua cases are.

A burn rate of 10% more seems a lot . . . ??? ¯\_(ツ)_/¯

 

[Ironworker]

Oh hey yes very interesting ! So how am I doing it ?28"bbl ? I also shot 140 JLKs 61.2 Ramshot magnum in FC Nickle plated brass. MV 3080 avg . 62.4 grs AVG 3,153 fps. Next 58grs of IMR8133 pushing a Berger 153.5 2,980 fps which was too hot,hard bolt lift ,only fired 3 of those.. ADG brass seams tougher .

 

[Straightshooter1]

Oh hey yes very interesting ! So how am I doing it ?28"bbl ?

Yeah, I initially though that might be the thing, but had that barrel length in the app.

When I got my 6.5 PRC early last year, I had a lb. of Retumbo and 58.0 grs. pushing Berger 140 Hybrids did outstanding for me at 3007 fps from a 26" barrel. Haven't seen any Retumbo on the market since!

 

[Beiruty]

I will run GRTools sims with those data

 

[Beiruty]

Initial sim with no tuning at all
At 53.5gr GRT MV is 2742 fps, Real average MV is 2750 fps.
Error is 8/2742fps = 0.291%
Now, let us plot linear analysis of GRT vs Average MV

 

[Beiruty]

Simple linear tuning

 

[Beiruty]

With Case Capacity "tuned" to 66.5gr of H20, the simulation lined up perfectly

 

[Beiruty]

I push 145gr MatchBurner at average of 3096fps from 30"
57.9gr of H1000

 

[Straightshooter1]

With Case Capacity "tuned" to 66.5gr of H20, the simulation lined up perfectly
View attachment 1305142

The big problem I had in looking at his MV's was not knowing the case capacity of his Nosler brass. With a case capacity set at 66.5 (well below that of my Hornady and Lapua brass), my QuickLoad MV's match up better to his MV's too.

 

[Beiruty]

The big problem I had in looking at his MV's was not knowing the case capacity of his Nosler brass. With a case capacity set at 66.5 (well below that of my Hornady and Lapua brass), my QuickLoad MV's match up better to his MV's too.

Even with the default case capacity of 68.0gr, the Simulation is close enough with less than 1% error.
"Adjusted" GRT MV 2944 fps vs MV 2959 fps 15/2944=0.5% error

I had a concern that the lower charge loads (48gr-50gr) do not track with the top charge loads

 

[Ironworker]

Lower charge load were what Vihtavuori posted . I skipped to Max loads and carefully beyond, I've settled on 57.1 grs and 147 gr ELD. Nosler brass is thicker than Hornady .