Long Range B/R

[woob614271]

I think this is why Tony Z and aJR like the 30s and 7mms so much; the stretch to the 1K isn't quite so unforgiving in wierd/tough conditions, with pulled/misread shots.

[Ned Kelly]

G'Day pete,
welcome to the forum, I really like our chat's when we meet, sorry to say I couldn't go to the crayfish the other weekend, took crook! So I'll have to reluctantly wait some more to give our BAT a proper shake down in a BR match!

Cheerio Ned (GW319)

PS when will you know about that 6x47 reamer delivery?

[petevm]

Since my server keeps dropping out I will try to keep the things brief.

Chapter 4
Still in Canberra at the 1K match. The 6.5/284 used only 15.5" of elevation compared to the 19+ of the 6BR , but the big surprise was the 300 Rem Ultra with 10.5" from 500mtr to 1,000yd. This thing is really stoked up. 96gn Re-25, 210 Berger for an estimated 3400fps. That's where the accuracy is best, but cases are good for only 1 or 2 firings yet bolt lift is easy (soft brass). 3 out of 35 cases left their fired primers on the bench. Just as well I do not waste time neck-turning for this one!!
Similarly, our experience with the 6BR in short range without neck-turning has led to the same in the Dasher and 6BR for Long-range. You gotta use either new brass (as we do for the 6BR) or F/L size every time. The projectile must be allowed to find it's home. It's a case of the tail wagging the dog, but it works. The 6.5/284 is neck-turned only because that's the way this re-cycled trade-in, and it's brass came to me.

Pete

[macca]

Hi Pete,
Do you mean new brass for the dasher and 6br every time you shoot or only for 600 and 1 k comps?I have read on several US sites that most of the really tight groups (at long range) were shot wilst fire forming brass for the 6mm.
That RUM is really flying!Bit of a bugger on the brass though.
Have a good one,
Macca

[petevm]

Macca, The 'no neck-turn' applies in both 6BR & Dasher. However I have to re-cycle the Dasher brass as it needs 'fire-forming' and has demonstrated some awful results in the process. 'Wildcat' cases that can be fire-forrmed with some shoulder contact often display incredible results ( once shot a .102" group at 100yds forming 220 Russian into PPC - never done better in a Match). The Dasher depends on the bullet being seated into the lands with reasonably high neck tension. This is ultimately a 'Variable' situation and typically can give some horrible groups. Yes, the 300 Ultra is now an expensive proposition but given it's short life expectantcy and it's limited use I can cope with tossing the brass after one firing if it will deliver the goods at 1K. However our spent 'once-fired' brass from the various 6mmBR rifles with Std neck chambers has a waiting list!!
Pete

[petevm]

Chapter 5

Load info for anyone that is interested -

6BR - 105 Berger or Lapua, CCI BR4, 30.5gn AR2208. .015 into lands, new brass.
6mm Dasher - 105 berger, CCI BR4, 32.4gn AR2208, .015 into lands, F/L sized brass.
6.5/284 - 140 Berger, CCI 250, 34.5gn AR2213SC, .015 into lands, F/L sized brass.
All loads are for moly-coated bullets in Maddco barrels, 1 in 8" twist in all the above.

Testing - Load developement should always be done at the shortest range that bullet stability can be assured. Occasionaly, boat-tail or VLD bullets wil give excellent grouping at 100yds - but this is not the norm. I prefer to test at 150 yds or more to ensure that bullet stability has been achieved. Reason for the shortest range is simply that we can deploy as many 'readable' wind-flags as possible. Furthermore, subject to your local range offering this option, always test in a direct crosswind - the 'vertical' in the group tells the story. Most of the elements controlling rifle accuracy at the firing point or in the rifle itself or the the load will generate more 'vertical' than random dispersion. If you can get a horizontal 'slot' your are ready for competition!

Pete

[petevm]

Apology, That 6.5 load should read 54.5gn not 34.5gn. (The slug would hardly get to the end of the barrel with 34.5) Pete

[petevm]

Chapter 6

Cartridge Brass - This likely to get a few noses out of joint!
Over many years of observation I have learned to be careful about 'generalised' comments regarding brass. The manufacturing process involves various annealing stages to offset the 'work-hardening' associated with the forming stages and will likely vary from lot to lot. This, in conjunction with the particular formulation of the brass alloy, can produce some wide ranging variations. If we assume that Lapua use the same basic material for the 220 Russian cases (that are the basis for virtually all the worlds benchrest 6mmPPC competitors) and their 6mmBR cases then why is it that the 6mmBR will barely exceed the PPC in velocity before showing serious head expansion? The BR case is definitely softer in the 'head' area than the 220 Russian - no doubt due to a variation in the annealing process. The only other factor in brass hardness is 'age-hardening' (often evident in the split necks of some really old loaded ammo). I have not the years left in me to put aside a few boxes of 'whatever' for use in 20 years.
Another hidden factor in generalised criticism is the 'badge-engineering' that goes on behind the scenes (my info is that Norma make the 300 Win Mag brass for Lapua as one example). I have no doubt that the major US makers also do some 'time-sharing'. As to the base brass - how many makers of cases have real control over the brass they recieve from their suppliers?
Now to some 'generalisations' -
Norma brass is almost always too soft in the head area for competition use (although nicely made)
Lapua brass is always nicely made and usually dimensionally OK but would be GREAT if it were harder across the board.
Remchester/Winington - very variable from calibre to calibre and lot to lot. Does not matter much if you are going to chuck it after 1 firing. (Tip for users of the 284 case in any cal - the original Win brass seems to be a bit harder in the head than others)
RWS - Now this is the real deal - almost always reasonably hard in the head area and ductile elsewhere. Dimensional tolerance is variable depending on calibre and, like most makers, do not offer all calibres. However, anyone wanting to go 'all-out' with some 'Wild-Cat' that is based on a case available from RWS would be ill-advised to use any other base case.
Nosler - So far, reports are that they are 'soft' in the head area.
Hornady - As above. Possibly these guys are trading off hardness for the precision that may result from softer annealing (we need a full-time metallurgist on this question)
Others that I have missed - Bad Luck. Not Enough back-ground to make a comment.
Oop's - PMC - Better than most would think - but very variable.
Bottom line is, of course, that if the application suits and the brass is affordable - then 'load-em', 'shoot-em', chuck-em'. No lost sleep over the reloadability of your cases!!!
Pete

[alpal]

Pete you're right about the "age hardening", I have experienced about a 5% split neck ratio in some norma .243 rounds I loaded about 30yr's ago with a mild dose of IMR4895. No other signs of problems
(eg blown primer pockets or cratered primers etc) and the rounds are still reasonably accurate.
I have about 200 rnd's mainly on second or third loading and as I use them up I will be annealing the necks, hopefully this will repair the problem.
I had never experienced a split neck in the days when this brass was new.
Regards Alpal

[woob614271]

Thanks Pete, input such as this is invaluable to us learners..
Cheers,
ol' wooby

[Klicker]

Pete - Agree with your comments on all of those I am experience with, I have found federal to be soft on both ends, primer pockets are all over the shop and I'm not pushing the loads very hard.

btw.. got the .263 bush and the trigger guard will do the job just fine mate.. thanks for the prompt delivery again..