New 6mm BR BBL Load Help Needed

[md1022]

Hello,

I am about to work up some loads for a new 6mm BR rifle that I will be shooting offhand. I have read everything I can on this site – and I must say it is a wealth of information but I still have many questions.
First my equipment info:

Nearly new Rem 700 action with new Hart 8 twist, .272 neck bbl, bedded into a Rem 40x tgt stock w/ CG Jackson trigger.

I have new Lapua brass, Wolf SRM, Wolf SR223, Fed 205, Rem 7 1/2 primers and Varget powder. I have Berger 80 PN 243080; Berger 90 PN 243090B; Berger 108 PN 243108T and Sierra 107 MK available to load. I have a Redding sizing die with bushings, a Forster Competition seating die and will be loading in a Forster Coaxial press.

90% of my shooting will be @ 100 – 200 yds w/ the balance @ 300yds although I will be shooting offhand I still would like to be getting the best accuracy I can without complicating the reloading process too much; due to work commitments I would like to spend the little free time I have behind a trigger rather than on the press.

I have no idea where to start my load development, thus these questions:

Because I am shooting at reduced ranges I would think the 80 and 90 grain Bergers would be good starting choices and a starting load of 29 grains of Varget moving up in .3 grain intervals to 31 as a possible high end load?

Then there is the whole jump / jam issue. Do I test for load and then adjust OAL, and if so where do I start – with a jump or jam and of how much??

I am measuring the length to lands with a Hornady OAL rod and threaded case but I find this bbl to be VERY different than any I have tested before. When I push the bullet to the lands with the lightest of pressure yet it seems to really grab the bullet, so much so that it takes significant pressure from a dowel inserted through the muzzle to release the bullet from the lands. Because of this I then changed my technique to counter balancing the pressure I exerted with the ram on the OAL tool with pressure from the dowel held in the bore from the muzzle, alternating pressure on both until I felt I was just at the lands. Using this method I found the lengths measured to be around .11” shorter than with the light touch push method. Is this normal or could there be something wrong with the chamber?

Lastly, which Primers to use? Obviously Wolf is easier to come by but I have 1000 of each of the above stated on hand.

I apologize for the long post and appreciate any assistance.

 

[coyotehunter]

I use Lapua brass with 107 sierra match kings. 31grns of Varget but dont go straight to that load its hot. Start some where around 29 - 30 grns and you should be safe. I am using CCI mag primers and have also had good luck with the BR-4 primers from CCI.

 

[Steve Blair]

You have everything you need and have made some very good equipment choices. The Remington 7½ is a fine primer. I use Wolf KVB-5.56M with RL17 and Sierra 107s but Varget and 7½ will work fine with all the bullets you listed. As Coyotehunter said, start at 29 with either the Berger 108 or Sierra 107 and work up in .3 increments. My usual practice is to seat to just touch while developing a load and then adjust the depth.

The Berger 80 Varmint is a very accurate bullet that has performed well for me in 6BR and 6mm Remington.

 

[MarkS]

md1022,

The 80 gr Berger is a great bullet out to 600 yds. The 90 BT is one of the most over look bullet in 6mm. I used it for 1000 yd benchrest with a 10 tw 6AI. I like N135 for my 12tw 6BR's with 80 gr Bullets, Varget for the 90's. Varget should be fine for 80gr also.
The Hornady OAL gage type can lie to you sometimes, I have been there. Make a dummy round and polish the bullet with steel wool, chamber the round. If the rifling marks are square, that is close to 0.020" into the lands. Then you can set everything from there. I like to shoot most everything in to the lands. I use Fed 205GM first when CCI BR4 if needed. Some gun use CCI if there is a cratering with the Fed's

Mark Schronce

 

[md1022]

Thanks for the replys. I favor the 80 and 90s as the chamber is a bit short throated. I will have to try the polished bullet technique and compair with the OAL gauge readings.

 

[Old Navy]

The 88 Berger, the 87 V-Max and even the Sierra 85 SPT shoot 2s & 3s in my 10 twist. Forgot mine likes the 90 Berger FB. Have fun. I am getting ready to put a new 8 twist on. I sure hope it will shoot all the ones I listed above. I have a lot of them on the shelf. Later! Frank

 

[forsyth793]

I am going to guess the Velocity was a little better than 2800 FPS and your SD was about 5......Great Group.........