6BR Rem, how to get it correct?

[goodgrouper]

Sorry Dave, I tried to give you a link to all the load data I worked up on both my 6 br's in fast and slow twists but I couldn't get it here. Run a search on it. I think I called it "6br load development results" or something like that. I listed all averages, standard deviations, and group sizes for each load and there were many.

I tried the 105's in the fast twist and had good luck with RL15 and Varget.

The slow twist likes Benchmark with 70 grain Blitzkings. 7mmrhb and I have used AA2230 in our br's with 55 grain BT's and it shoots REALLY FAST! 3900 fps plus is common with no pressure! It works for the 65's too.

Oh, and by the way, there were several versions of the original 6br designed by Jim Steykl of Remington. One had a much shorter neck and another had a slightly different external dimension to the case. It would be advantageous to find out how old the reamer was that made your gun if possible.

 

[Dave King]

Some range results, observations and questions.


I shot yesterday trying one load and three different groups of brass.

BRASS:
Set "A" of brass was just prep'd with a ~.2605 neck with a loaded bullet.
Set "B" was a once fired set of brass of ~.260.
Set "C" was newly prep'd with ~.261 neck.

Load:
I used 29.0gr of H322, CCI BR4 and Clay Spencer 68gr bullets.

Shooting:

I used .230 as bullet hole diameter (value to subtract) for calculating group size.

I fired one fouler (producing a very small group).

Set "A"
Group 1: .2605 neck three shots = .159" (.327 tall x .290 wide)

Group 2: .2605 neck three shots = .166" (.335 tall x .368 wide)

Group 3: .2605 neck three shots = .247" (.477 tall x .288 wide)

Group 4: .2605 neck three shots = .520" (shot by a range visitor) (.750 tall x .546 wide)



Set "B"
Group 5: .260 neck five shots = .428" (shot by a range visitor) (.536 tall x .585 wide)

Group 6: .260 neck three shots = .477" (.707 tall x .323 wide) (one round chambered "loose")

Group 7: .260 neck seven shots = .702" (.865 tall x .634 wide) (there are two fliers and two rounds extracted hard -hot rounds-) The two fliers are high by ~.4"


Set "C"
Group 8: .261 neck five shots = .892" (.814 tall x .941 wide)


Set "A" again for verification

Group 9: .2605 neck five shots = .330". (.561 tall x .546 wide)


I did not clean the rifle between groups.

There was some mirage from the barrel (cool day ~55F) but I waited until it was clear before shooting the later groups.

I shot from a bipod and sand sock.

The scope is a Leupold 6.5 x 20.

Distance 100 yards.

Wind = ~null

Wilson seater OAL = ~2.220 (.020 over stated max length but not touching the lands.)

Neck bushing in resize die = .259"

I'm curious as to why some rounds seem hot (extract stiffly as compared to others on the once fired brass).

With the case necks so thin (~.009) is there a special method to anneal them?

For my 308 brass I use a tub of cold (iced) water, a ~1" blue propane flame and a count of 10 with the tip of the flame touching the middle of the revolving case neck. For these thin necks I'm thinking I'd melt the neck even with a short count.



Note: The point of impact on groups 1,2,3 and 8 are primarily due to scope adjustments.