Congrats of owning a 6.5x55mm, which is probably the best shooting cartridge ever developed.
I have more than a few....
A couple points...... While Winchester brass is OK.... It is slightly undersized as are ALL US made 6.5x55mm brass casings. PMC is the worst,,, wel no I take that back,,, Igmann brass is the worst... Followed by PMC which is super undersized. and of course the crappy Remington brass.
The best brass for the wonderful 6.5x55mm is LAPUA, closely followed by Norma. Then Privi....
So you will look up the price for LAPUA brass and about have a heart attack. But remember ,,,, it is a 100 round box and they can be reloaded 10 to 14 times... About twice as much than Winchester brass, because they do not stretch in the case web area.
CCI -200 work great... Even better is the CCI BR-2 match primer.
The length of the bullet and not the weight is the issue with rifling twist rates. The Berger's are long, but your twist will handle them just fine.
Also remember that the 6.5x55mm is usually loaded with the bullets further out of the case neck than you see on most modern cartridges.
BERGER 130gr VLDs 3.140 inch COL.
47.0 grains RL-19
Lapua CCI-200
CG-63. 3.0 inch group, 2,850 fps
46.5 gr RL-19 1.0 inch group
3.110 col 2,790 fps
here are some loads from my 22 inch barreled M-70 featherweight
6.5x55mm Winchester MODEL 70 LOADS ONLY
Federal factory 140gr Soft Point:
= 2,375 fps, 0.50 inch group.
120gr Nosler Ballistic Tip: 46.5gr RL-19, Lapua, CCI BR-2, 3.085 col
= 2,560 fps and a 1.0 inch group
120gr Sierra Match King: 46.0 gr RL-19, Lapua, BR-2, 3.085 col
= 2,508 fps and a 0.50 inch group.
120gr Hornady A-Max, 48.8gr IMR-4831, ww,ww, 2.964 col
= 2,925 fps and a 0.75 inch group Lee Crimp. High Pressure
129gr Hornady SST, 47.3gr IMR-4831, WW, WW Stand, 2.942 col
=2,808 fps and a 1.5 inch group. no crimp. Cratered primers
140gr Rem Accu-Tip, 47.0gr RL-22, Lapua Brass, CCI-200, 3.970 col
= 2,640 fps and a 1.0 inch group
140gr Nosler Partition, 47.0gr RL-22, Lapua Brass, CCI-200, 3.950 col
= 2,569 fps and a 1.5 inch group
140gr Hornady Soft
oint , 47.0gr RL-22, Lapua Brass, CCI-200, 3.850 col
= 2,575 fps and a 2.0 inch group
140gr Hornady SST. 46.5 gr RL-19, Lapua, CCI-200, 3.090 COL
= 2,570 fps and a 1.0 inch group
140gr Hornady SST, 44.5 gr H-4350, Lapua, CCI-200, 3.090 col
= 2,608 fps and a 1.5 inch group
140gr Hornady SST, 44.5gr H-100V, Lapua, CCI-200 3.090 col
=2,669 fps and a 0.50 inch group.
140gr Sierra Game King, 44.5gr H-100V, WW, WW, 2.930col
= 2,675 fps and a 0.55 inch group Lee factory Crimp, no pressure signs
140gr Hornady Soft Point, 44.5gr H-100V, ww, ww, 2.945 col
=2,680 fps and a 2.5 inch group. Lee Crimp. Some pressure signs
140gr Hornady R. N. 44.5gr H-100V, WW, WW 2.975 col
=2,620 fps and a HUGE Group, lee Crimp
140gr Hornady SST, 46.5gr IMR-4831, ww,ww, 2.995 col
=2,700 fps and a 0.75 inch group, primer flow
160gr Hornady Round Nose: 45.0 gr RL-22, PMC, Rem 9.5, 3.100 col
= 2,288 fps and a 1.5 inch group