6BR Load Dev, Velocity and Heavy Bolt Lift

[LCazador]

Thanks all for all the tips. I will do another session with now fireformed brass and report the results. Do you recommend cleaning the barrel, leave it, or just clean the carbon with C4? The barrel has about 100rds so far.

A thorough cleaning is in order! Especially the carbon ring at the end of the chamber. Also after cleaning make a note of how many rounds it takes to foul the barrel. Shoot the number at every range session. I usually make a note in my reloading notes on number of foulers for each chamber. Expanded case heads lead to excessive gun handling and in turn inconsistent groups in a competitive situation.

 

[03machstock]

29.8 with 105 Berger hybrids .005 off & .001 neck tension gives me 2867 fps. & about 1/4" group but 2nd & 3rd firing on brass. 26" barrel 1:8 no turn necks

That’s smoking fast for a 6br with a 26” tube isn’t it? What powder?

 

[BW64]

That’s smoking fast for a 6br with a 26” tube isn’t it? What powder?

Varget

 

[Janeau]

New brass should be sized and chamfered. Thats basic.
30.0 gr Varget is the powder I use with 105 Lapua Scenar. Wotk great.

 

[Fire Dog]

My new 4kg {8.8lb jug of AR2208 {Varget} was really slow and when checking with a couple of other club members got the same reply...
Formally using 30.1gr behind Sierra 107's in 28" Benchmark was getting 2850... New stuff down to about 2765... Just worked up a powder test to get it back grouping {3x 1 hole at 110yds = 100mt} at 2850 and now driving the 107's with 30.7gr...
The 30.1 still shooting and grouping but just about 100fps slower..? CCI450's to light it all up.
Peterson 6BR brass with now at least 15-20 loads and going strong.
I can definitely tell that the load seems hotter but it is shooting well and I have recently started to give the brass a touch of Rollsizer treatment as when I got a 6BR Wilson seating die the cases were just slightly sticking in the die and needing the tip of a spoon to pry them out...
Previously only a shoulder bump and neck size then mandrel before a Foster seating die and the rounds chambered fine so the Wilson seating die is just a tad tight compared to my chamber but they will hone it to suit for free as long as I send a few fired cases and pay postage both ways... A reasonable situation I think.
In the mean time the Rollsizer gets the job done with a few thousands reduction to the 200 line.
The 107's at 2850 produced a 200.14 at 500yds.

 

[RangeDust]

My new 4kg {8.8lb jug of AR2208 {Varget} was really slow and when checking with a couple of other club members got the same reply...
Formally using 30.1gr behind Sierra 107's in 28" Benchmark was getting 2850... New stuff down to about 2765... Just worked up a powder test to get it back grouping {3x 1 hole at 110yds = 100mt} at 2850 and now driving the 107's with 30.7gr...
The 30.1 still shooting and grouping but just about 100fps slower..? CCI450's to light it all up.
Peterson 6BR brass with now at least 15-20 loads and going strong.
I can definitely tell that the load seems hotter but it is shooting well and I have recently started to give the brass a touch of Rollsizer treatment as when I got a 6BR Wilson seating die the cases were just slightly sticking in the die and needing the tip of a spoon to pry them out...
Previously only a shoulder bump and neck size then mandrel before a Foster seating die and the rounds chambered fine so the Wilson seating die is just a tad tight compared to my chamber but they will hone it to suit for free as long as I send a few fired cases and pay postage both ways... A reasonable situation I think.
In the mean time the Rollsizer gets the job done with a few thousands reduction to the 200 line.
The 107's at 2850 produced a 200.14 at 500yds.

I got the same 8.8LB jug that I am using for this load dev. I managed to get to the range on Friday. I will post it here tomorrow and compare results. Thanks for your feedback. BTW no heavy bolt lift at all on the second firing of the brass.