6BR/Dasher/BRX and velocity for 105-107s

[2dogs]

Fellow rifle bugs,

I find myself pretty frustrated with my Remington 700 243. Although it has a 26 inch barrel I feel I am burning WAY too much powder for the return in performance.

I am interested in going to one of the 6BR cartridges, standard or improved. I want to run the 107 Sierra to 1000 yards in S. Texas winds which can be pretty tough. I have done quite a bit of reasearch, and find guys will list thier velocity with a given 6BR/Dasher/BRX cartridge but leave out either which bullet they are shooting or how long and what twist barrel they are using. Or if they give the other information they leave out the velocity.

I know that each rifle is a rule unto its own and performance you see I may not see but maybe you can take a minute here and tell me what you would recommend as to which 6BR variation, barrel length, twist, and velocity that you have experience with. If you are having tremendous success with say a 90 grain Berger please dont leave that out along with your load.

My thanks in advance.

 

[fdshuster]

6 BRX, 33 grs. of Varget, Sierra 107 MatchKing, touching, BR4, Krieger 26", .237" bore, chronographs at an average of 2930 fps. p.s.: Knew I'd forget something/ 8 twist.

 

[brxbrad]

6BRX, 33.2 grs Varget, 105VLD, 26" Kreiger Barrel, 1:8 Twist, 3030 FPS, Compete in both 600 and 1000 F-class with it. Extermely happy with this gun.

 

[2dogs]

brxbrad, can you tell me what Die set up you use for your BRX? Thanks guys!

 

[gmorganal]

33.3 grs of RL-15 in a Dasher case = 3,050 FPS
34 grs of RL-15 in a Dasher case = 3,115 FPS

This is with a 105 VLD Berger.
Last load will loosen the primer pockets.

 

[2dogs]

gmorganal, how long is your barrel and what is the twist please?

 

[CaptainMal]

6mm Dasher, 30" Krieger 1-8 twist. 107 SMK Sierra's, 32.9 gr. Varget = 3003 fps.

 

[gmorganal]

I have a 30-inch Krieger barrel on my 6 Dasher, and it is an 8-twist.

 

[2dogs]

Still looking for answers here! :-\

 

[newboy]

2dogs ,

I ran a test @ bisley 3 years ago with strait br brass against the fully fire formed brx .

the range was 1000yrds (stickle down) , shooting 30.5 grns of varget topped by a107 smk for the BR

BRX went in at 33.8 grns of varget same SMK 107 .

The result was the BRX gave me 3 minuets less elivation needed , thats the gain i had for just about 3grn of extra powder

30 inch pacnor barrel 8 twist

 

[AckleyImproved]

Dasher, 28" barrel

during pressure testing got to 3113fps before stopped. Primer at firing pin starting to extrude.

Normal running 3020-3030fps.

 

[2dogs]

Newboy, do you remember what the velocity for each caliber was?

 

[bozo699]

Newboy, do you remember what the velocity for each caliber was?

2dogs,
One was a 6br the other was a 6brx so both were the same caliber (.243) the brx has the shoulder of a 6br blown forward .100" which will give it about another 3.5 grains more capacity then the standard 6br, the 6br runs in the neighborhood of 2850-2950 with a 107 give or take a little the 6brx or the 6Dasher will do about another 100-150 fps more then that, my 6brx with 34.0 grains of Varget, Lapua case, 205M federal primers with a 107 SMK 28.5" Krieger 1:8 twist .237 bore at 3565 feet in elavation 86* 30% humidity is running 3050 fps, my dasher with a 107 SMK 27" Krieger 1:8 .237 bore 32.6 grains of H-4895, cci-400 primer, Lapua case same enviromental conditions as the brx is 3030 fps, I have heard some guy's getting over 3100 fps but I don't want to push mine that hard if I want 3100+ I will use my .243 or 6mmAI or 6*284. Improving the 6br cartridge doesn't make it a super magnum it simply gives it a small velocity edge to help push those 103s-108s through the wind just a little better without giving up the inherent accuracy of it's original form the (6br) I can't explain it any better then that for you I hope it helped some.
Wayne.

 

[2dogs]

Bozo699, Thank you very much for your well written reply. I read it very carefully and dont want you to have the impression I dont get the difference between the different BR cartridge variations as I have studied them pretty carefully. What I am trying to get a grip on is what is the best barrel length for my goal which is a 107 SMK at 3050 fps. I can see that bore diameter will be factor and note that quite a few people use Kreiger barrels. I have quite a few Hart barreled rifles and never owned a Kreiger and may have to get myself one that will finish at 28-29 inches or so.

Again, thanks for taking the time to answer, it is very much appreciated.

 

[bozo699]

Bozo699, Thank you very much for your well written reply. I read it very carefully and dont want you to have the impression I dont get the difference between the different BR cartridge variations as I have studied them pretty carefully. What I am trying to get a grip on is what is the best barrel length for my goal which is a 107 SMK at 3050 fps. I can see that bore diameter will be factor and note that quite a few people use Kreiger barrels. I have quite a few Hart barreled rifles and never owned a Kreiger and may have to get myself one that will finish at 28-29 inches or so.

Again, thanks for taking the time to answer, it is very much appreciated.

2dogs,
You are very welcome, I hope all the information was accurate, I believe it was if someone else thinks not please chime in and help out. All my competition rifles have Kriegers on them, I don't really know why they just do. I have at least 10 Hart barrels and not one single complaint, I have several different brands of barrels on my hunting and varmint rifles and the Harts are by far my best shooting rifles, so if your happy with Hart I would stick with them, however if you look at some of the bench rest shooters equipment the long range stuff anyway you will see a large part Krieger and only a very small part Hart. I was told by one of the Top shooters at the Deep Creek range in Montana that 28.5" was the optimum length for a dasher barrel, some run more some run less but the top guy's seem to run around that # from what I have seen anyways. Just a side note, my gunsmith is also one of my long range shooting partners we built 4 rifles with my reamer, three of them had Kriegers, all the same length, and all with .237 bore, we broke all three of those rifles in here at my place, 1260 feet above sea level and around 60* Pauls was running about 30 fps faster then mine at the time at about 3060 and his sons was about 3004 if I remember right and mine was 3030, so as you can see not all barrels are the same even though you buy them as the same, also I was shooting 1/2 grain more powder then they were, mine was one lot and Pauls and his sons were another lot so that is something to keep in mind as well, I have heard Varget is noted for that, have you read the articles from here on 6br about the 6br and variants? here is a link to get started if not, I know you have been studing them but you would be surprised the amout of members that really haven't searched this valuable site there is a lot to offer.
http://www.accurateshooter.com/cartridge-guides/6mmbrimproved/
again I hope this helps some.
Wayne.

 

[newboy]

2dogs sorry about the time delay as you can see iam in the UK, As Bozo stated the mv was right about were he has his BRs running , your quite right to look very long and hard at 6mm barrel makes as some 8 twists shoot bullet weights better than others .My Pac Nor did not shoot as well with 105/107 range heads , 95 grn heads it just hammered small groups .
From what Ive read and seen the right length seems to be 28/30 inches and bore dia is the key point to bullet barrel Harmony .

 

[2dogs]

Well, I did manage to find a little joy with my 243 today. 90 grain Berger match bullets and 44.5 H4831SC gave me 1/4" groups at 100 yards! I guess Im going to have to go ahead and keep this one the way it is for now. Good thing I have other donor actions!

 

[GregT]

2dogs, my 6BR is getting 2960fps (it was +/- around 10fps over 6 shots) with a 108gr Berger using 30.2gr of 2208(Varget) from a 1/8 twist, 22.5" long barrel.

 

[2dogs]

Wow Greg, that one must be a superior barrel! ;D

Most of the others seem to be quite a bit longer for that same speed.

 

[bozo699]

2dogs, my 6BR is getting 2960fps (it was +/- around 10fps over 6 shots) with a 108gr Berger using 30.2gr of 2208(Varget) from a 1/8 twist, 22.5" long barrel.

2dogs is right that is a super barrel for sure!
Wayne.