6BR Loading, Seating depth, etc. questions

[WyoWindage]

I just received 300 Hornady 105 BTHP .243 bullets, #2458. The box doesn't say Match, the Hornady website does. Probably doesn't make much diff? I have been shooting Horn 87 VMax, and today, I tried 5 rnds of Sierra 107 MK, that I tried to remove the molly. 29.8 varget, about 2775 fps on my chrony. Have about 50 rounds total thru my 6br so far, and accuracy not esp encouraging, yet. Best 5 shots at 100yds about 0.7". Will try the 105g Hornady next time. Any tips on seating depth and powder charge. I have Varget, R15 and AA2520. Are the 105 BTHP similiar to the 105g AMax? Why the 2 kinds if they are both target type bullets? AMax for varmints, maybe? This in my new McGowan 8tw, Savage M12. Thanks. Ron.

 

[ShootDots]

The "A Max" is more of a VLD than their Boattail. The A Max sports a secant ogive and I believe a 17degree boattial. The Boattail is a tangent ogive bullet with, I believe an 11 degree boattail. Not sure on the exact degrees of the boattails in each bullet, however, I am close enough for government work. You will have an easier time (probably) finding a good seating depth with the boattails because of the tangent ogive design. I would begin seating them at 10KOFF... use either Varget OR RL-15 and go from 29grs. and work TOWARDS 30.8grs WATCHING FOR PRESSURE.. My guess is that right about 30.2-5grs. you will find a "sweet-spot"... Use CCI 450 primers.. Once the sweet-spot is achieved, start playing with seating depth from about 7-8K INTO the lands to as high as 30K OFF the lands. Chances are you will find something to your liking>>like tiny little dots at 300 yards on occasion!!

 

[WyoWindage]

Great info. Will give it a go with the Hornady 105's. Is their a sweet spot velocity I should be looking for? The 30BR seemed to shine at 2950 to 3050. Has the 6BR a speed where it shoots the 105gr'ish best. I think the Sierra 107g may need about 2900fps (only from what I have read). I only got about 2800fps with 29.8g Varget. Maybe I will try about 30.2g. Would like to start the Hornady's with a little more than 28g varget. Did you mention that as a safety valve start, or are there some that do best with the lighter loads? Most of the loading tables I have seen don't go much higher than 28.5 gr Varget, maybe 2800fps. These ain't no ppc's, esp. with factory Savage actions, where 3300 to 3400 seem's normal (68gr bullets). Just getting aquainted with my rifle, not really sure what it will do, velocity wise and I realize fast don't always mean accurate. Will keep my progress posted. Thanks for your help. Ron

 

[ShootDots]

In my 6mmBR I load 30.3grs of Varget with CCI 450's and 105 berger Hybrids... I am running right at 2840f.p.s. with e.s.'s at about 6f.p.s. or so.. In MHO 2900f.p.s. from a 6mmBR is stretching the envelope past the end of the table! Stay in the low to mid 2800's and you will do just fine..

 

[saunaking]

I could never get the A-max bullets to shoot jumped until I realized that their ogive is secant. Here is a picture of a recent outing with a new 6BR that I was doing load development with.
5 shots at 100 yards. This is seated to the lands. Before anyone comments on the OAL written on the target, my measurements are taken with the comparitor attached to the caliper and that number is used to make it less confusing for this old man. ;D The 105 A-max is impossible to find right now in my world.

 

[Forum Boss]

In my 6mmBR I load 30.3grs of Varget with CCI 450's and 105 berger Hybrids... I am running right at 2840f.p.s. with e.s.'s at about 6f.p.s. or so.. In MHO 2900f.p.s. from a 6mmBR is stretching the envelope past the end of the table! Stay in the low to mid 2800's and you will do just fine...

All depends on the Barrel and the bullet. But I agree that one shouldn't try to get extreme velocities with a standard 6BR.

But barrels do make a difference. I shoot the Scenar 105s in 6BR with 30.3 Varget in a 27" PacNor with velocity right around 2910. Shoots Great. YMMV. I think 2850 is a reasonable figure in most barrel.

 

[WyoWindage]

Target from this morning. Eight 3 shot grps @100Yds. 29.5g to 30.2g Varget with Fed Match primers and 29.5 to 30.0g RE15 with RSR primers. Hornady 105 BTHP jammed. Chrony showed 2708, 2726, 2741 and 2782 fps ave with 4 Varget loads. Not one dang reading with the RE15, it must not like that powder. Three of the best groups were on the lower end of both powders. Guess I will try a tad more next time. No pressure signs yet. Sure wish I had some of those magic CCI primers. Thanks. Ron.