VV N160 - compressed loads in 6.5CM

[Gandy]

1 hour ago, Mick Miller said:

Dildo's for dwarves?

Dildo, dildo; it’s off to work we go...

[gyr]

I tried the N160 with Scenar 139 and the Hornady ELDM 140, small primer Lapua brass, Murom primers.

Lapua SP brass, Scenar 139, V 160 42,5 grains= 2578 ft/s.

Lapua SP brass, Hornady 140 ELDM, 42 grains=2498 ft/s.

24" barrel.

 A little disappointing.

Either I go for bigger loads or try RS62 ( RS62 is single base , right??)

 

 

[VarmLR]

For comparison in a 1/8 twist 24 inch barrel, same brass, same primers (KVB Magnum....just thicker cups), same bullet, RS62:

43.9grn RS62 = MV 2,700fps 139 Scenar

42.6grn RS62 = MV 2600fps 142 Hornady SST

Yes, RS 62 is single nitrocellulose base but coated with camphor to improve temperature stability.  It's energy (heat of explosion) is similar to H4350 which was the go-to powder for 6.5CM.  Kinder on barrels than RS60 and doesn't appear to pressure spike like some Vhit powders. (some have a tendency for most velocity gain at the top of their pressure curves and combine that with temperature sensitivity and pressure spikes can be quite spectacular!  I've experienced this with N140...don;t know if N160 is the same).  Note that RS62 has a higher energy than N160, and greater bulk density so you can get more into the case before compressed loads start.  I have mixed feelings about compressed loads.  On the one hand, you get uniformity with slight compression of load density and hence ignition and burn rate, on the other with just slightly more compressed loads you can crush the kernels and increase rate of burn slightly in doing so depending on the energy of the primer used.  Small primers seem more consistent with compressed loads in 6.5 I guess because they have lower ignition energy than large primers but that's not fact, just speculation based on results.

 

[KABOOM]

On 8/26/2019 at 11:47 PM, MichalS said:

I started experimenting with N160 in 6.5CM

The book max for 139 Scenar is 42.1gr at 2.717" COAL. I got a bit surprised when I heard a cracking noise of compressing powder as the data don't indicate it should be compressed... What's even more interesting is that Scenar 136L data go up to 46.0gr...

Anyone have experience with compressed loads of N160?

TIA,

Michal

Not with that powder but yes compressed loads, haven't seen trouble at all honestly.  Brass varys some less room others more.