6mmBR velocity spread

[eddywitay]

Hi guys,

I have some questions about my standard deviation and extreme spread. Well first i will start by telling you a little about my rifle.
IT sports a Remington short action that is all blueprinted It has a 26.inch1-8 twist hart barrel that has diamond flutes and a muzzle break.The stock is a Bell and Carlson A-2 style but that will soon be replaced with a Mcmillan A-2 that was ordered two weeks ago.Jewel trigger set at 4oz. and a Leupold VX-3 6.5-20x50 with target dot.The chamber is a no turn chamber I use a Redding 264 ti. bushing that gives me three thousands of tension. I am shooting Hornady 105A-Max 29.0 grains of Varget federal 205Mprimer and Lapua brass. The 100yd group is great it measured .240.Now on to the numbers first shot 2654,second shot 2681,third shot 2663,fourth shot 2654,fifth shot 2658.That gives me a average of 2662,E.S 27,S.D 11. Now this is not a 1000yd bench rest rig I use this for hunting woodchucks here in eastern PA. some shots can be far 1000yds. I would like to get the E.S and SD in the single digits. I also have different size bushings that will give me two thousand & one thousand neck tension will that help me ?Maybe one of you thousand yard BR shooters can help me.

Thanks

 

[Forum Boss]

In normal parlance, SD refers to Standard Deviation. Like Donovan Moran, I generally am more concerned with ES (Extreme Spread). But get your ES down to low teens or single digits and your SD is going to be darn low as well.

Statisticians would opine that SD is more meaningful. But that Extreme Spread can certainly "bite you" with vertical, even if it's only one shot in a string.

Powder choice can have a big impact on ES/SD also. In my .260, my loads with N550 never came close to the low ES/SD I got with H4350 -- using the same reloading methods.

 

[eddywitay]

I was just thinking about upgrading to a sartorial scale I think that that is my only option if It is a good practice to get under 1- tenth how do I control seating force? I use a harrells turret press to seat bullets.what about primers should i try cci.br4,or something like that.

 

[boltfluter]

This first thing I would do is to try a CCI-450 magnum primer. In my 6BR it makes a huge difference in the E.S. Usually under 15 f.p.s. Hope this helps.
Paul. 8)

http://proprecisionrifles.com/

 

[cmillard]

i have switched to wolf primers exclusively for starters. second, i found that the further i jammed my bullets (berger hunt vlds), the more consistent my velocity was. ITL .025 is where it shoots single digit sd and stellar accuracy.

 

[ShootDots]

Hello Eddy.. I have a 6mmBR that I use for F-Open. I shoot 2 loads. 1.) 105 Bergers set 15K OFF the lands. I use 30.4grs of N150 and a CCI BR-4 primer. I neck turn ONLY the "high spots" and have a 2K neck tension that I use on ALL my cartridges. I get 2860f.p.s. with a 4 S.D. Load#2: 108 Berger seated 15K off the lands. It uses 30.6grs. of VVN540 and a CCI 450 primer. It sends that pill off at 2840 with a 9 S.D. With all that said, I believe you MUST have a few things in ANY cartridge to get LOW E.S. and S.D.'s. 1.) You must find a powder or powders that your particular rifle LOVES. You then have to mate that powder with the correct primer>>I have found primers make a BIG difference in accuracy as well as E.S. / S.D. 3.) Neck turn your brass>>it does NOT have to be turned all the way down>>just get rid of the high spots. 4.) Neck tension should be NOT more than 2 K if you have seating depths where your bullet is OFF the lands and NOT more than 3K if seated HARD into the lands. Follow these little "musts" and you will not only get accurate loads, they will have very tight velocity spreads so you can shoot nice groups out to 600 yards or so..

.................Ben.............

 

[wilbur300wsm]

things to try; sort bullets by bearing surface, sort brass by weight (the brass you have), measured load consistency (good scale). try diff primers, the DO make a huge diff. i run no neck turn 6brs, but i do sort my brass by weight and neck wall thickness. ive used a lot of diff powders with success. like other guys have said, you just have to find what your gun likes. exampl: my one br barrel liked varg at close range (100-300) but not at longer range (500-1000). rl15 worked for the longer stuff. another barrel didn't like anything but vv n540.
my current load that won mifflin county ground hog agg. vv n540 (30.1gr), 108 bergers (.05 jump), 1 1/2k neck tesion, cci 450. broughton 8t, 2880vel, single es.

p.s. make sure the inside of the case necks are dry from any sizing lube. trust me this will gives you inconsistency bullet grip, (tension)


hope this helps

 

[eddywitay]

Thanks fr the help guys..