300 Meter dilemma

[westerngrizzly]

Ok guys. I am new to this forum.
I have a dilemma as to what caliber I should build a 300 Meter Free Rifle in. I am debating between the 6 Dasher, 6X47Lapua, or the 6XC. I am really leaning towards the 6X47 Lapua.

For those of you who that are unfamiliar with the courses of fire they are as follows.
Mens prone event:Unlimited sighters and 60 shots in a time limit of 1hour 15min
Mens 3X40: Prone-Unlimited sighters and 40 shots in 45 min
Standing-Unlimited sighters and 40 shots in 1 hour 15 min
Kneeling-Unlimited sighters and 40 shots in 1 hour

The rifle max weight is 8.0kg(17.6lbs) and muzzle breaks are not allowed.
The ten ring is 100 mm across. the X ring is 50mm.

 

[spclark]

6BR is the most prevalent cartridge used for this, the others providing more horsepower for longer distances but with more recoil to deal with in offhand & kneeling.

The order you mentioned the other possibles has them increasing in case capacity....

http://www.gun-club.net/handbook/doku.php?id=page15

http://www.6mmbr.com/300m.html

http://www.accurateshooter.com/competition/300m-competition-guide/

 

[Laurie]

Lapua developed the 6.5X47 for this discipline, the logic being similar accuracy, similar ballistics but longer barrel life because of the reduced powder charge to bore weight ratio. That's why factory 6.5X47L is loaded 'soft'.

You quote the course of fire and it's a lot of rounds. Likewise, ISSF 300M shooters practice a lot. Although 6BR gives good barrel life compared to some, that sort of ammunition expenditure adds up and barrels wear out. If you're like we are in the UK as per good specialist custom gunsmiths, a shot-out barrel can see you out of action for half a season, or require either a premature winter re-barrel, or having two expensive top quality rifles being built to ensure you're not thrown hors de combat mid-season. On that basis, the 6.5X47L makes a lot of sense. Definitely NOT the 6X47L - more performance than you need and barrel life reduced over 6BR.

I'm not an ISSF shooter myself, (but shoot 6BR, 6XC, and 6.5X47L in other disciplines), so don't know whether Lapua's logic has convinced 300M shooters to switch - I suspect not given how good the basic 6mm Norma BR is in this role. It will certainly take some beating. I can't see you getting any benefit from a 6 Dasher at 300M, but you will reduce barrel life a bit, or maybe more than just a bit. 6XC has a barrel accuracy life of 2,000 rounds or thereabouts. If you shoot the equivalent of two matches in practice shooting for every match you enter, that's 2,000 divided by 360 = less than 6 matches. Doesn't look a good idea to me!

Laurie,
York, England

 

[RDavies]

Another problem with the bigger 6s could be fouling. With unlimited sighters and 40 shots, some barrel/powder combos could be getting fouling problems towards the end of a relay, where as the lighter powder charger, slower bullet speed of a 6BR, or a lightly loaded Dasher will be cruising along.

 

[skeetlee]

i am going to have another 6ppc barrel chambered up for our 300 yard f-class match. I may or may not go with a 12 twist barrel. i may just stick with a 13.5 and shoot 70gr bullets. I feel this will give the best accuracy and n133 burns very very clean!!