Going to throw together a Rem 700 LA i've had for some 33 years, a 24" #3 Hart fluted barrel and set it down in a D'Arcy Echols Shrike stock. Caliber? Dave Kiff calls it the 6.5x57BR. Lapua 8x57 brass, necked down to 6.5mm and shoulder blown out to 30 deg. Running Barnes 127 LRX, 130 TSX and 140 Partitions, what velocities do you think I'll get?

Alan

Guessing 2800-2900 with the 127's; 2750-2800 with the 140's.

Blown out should make it about like a 256 Newton or 6.5/06 I'm guessing (?).So maybe a skosh more(?).

This off the top of my head. Maybe someone can do the math with capacity etc.

It sounds like a 6.5x57 Improved.

Sounds like fun!

If it has the case capacity of a 6.5-'06:

The new wave around here with the advent of the 6.5 SAUM, it to run a 6.5-'06

Same velocities with the 140's without the brass prep/sourcing problem.

Two of my buddies finished RU and 3rd in the Steel Safari running the 6.5-'06, H-1000, and 140 Berger Hybrids at the speed limit...

3170 fps...

Rick,

I'd say case capacity is about 1/2 way between a 260 and an '06 case.

Alan

I was thinking along the lines of Bob and the 6.5x57mm as a basis for velocities. Granted I don't know the details of the 57BR, but Quickload indicates 2900 fps with the 140 partitions isn't a hot load so I would think the blown out shoulders would allow 2900 fps with no issues.

I'm thinking this case geometry could take advantage of the slower burning powders for the heavy 6.5 bullets...like people do with the 6.5 Swede.

Sounds like a cool round!

Barrel length?

My new 6.5-06 has been to the range 10 times in the last 4 weeks.

9-23-2015 range report:
120 gr Nos Bal tip moly with 50.7 gr IMR-4166 powder 3.34" , Win 30-06 brass, that QL estimates at 3236 fps 65 kpsi using IMR-4895 in the QL library.
Chronographs at 3197 fps
Averages 0.92" 5 shots at 100 yards

8-22-2015 range report 6.5-06
Quickload predicted 2977 fps 67kpsi 142 gr Nos Accubond long range, 54 gr H4350, 3.34" 24" barrel
Chronographs at:
2982 fps
2956 fps
2873 fps

*That jug of H4350 is usually 4% slower than the H4350 in the QL library, but the bullet jammed into the lands has higher start pressure and offsets the slow jug.

*That jug of IMR-4166 is right on the money with a couple of cartridges using the IMR4895 constants in the QL library.

2,989 fps for the 127 LRX and 130 TSX

2,875 for the 140 partition...

Custom rifle, wildcat handloads, and no chrono?

Where did you get that? He is asking, prior to the build, what velocities he might see.