Advice for 'fly gun'

[conquistador50]

Gentlemen,

I am developing a 500yard benchrest rifle called a 'Fly Gun' in
Australia.,The target ten ring has a blow fly in it)

It is presently chambered in 308 Baer. I intend shooting 220gn Sierra Match Kings out of it. The powder I am testing is a,slow) 20mm aircraft cannon powder.

In initial tests, I've establised 3200-3400FPS muzzle velocity with very good accuracy at 100 and 200 yards, however, the 300Weatherby Magnum cases I used resulted in over expanded primer pockets after two firings.

Question: What cases should I use; and what length should I cut the barrel to,see attached)

 

[Rinso]

Mate turn up to the Procal Fly shoot at Canberra on Sept 23. You will find out all sorts of good info. I am pretty sure at least one 308 Baer amongst the regular attendees.

 

[Sooner04]

Not sure where you are still at with this; but I happend to shoot a .308 BAER in 1000 yard competition. I shoot the 210 Bergers and the 220 Sierra's with RL 25 but I have them around 2950fps. The barrel is a Krieger 1:10 twist and 30 inches long.

3200 and 3400 fps using Norma brass will kill it. I don't like Norma's 300 wthby brass anyway; the best brass I have come accross is either the new Nosler custom in 300 wthby or Weatherby's own 340 wthby brass.

The 340 brass is really the way to go because after you trim and turn and fire form your neck walls are much thicker than Norma and I have very few primer pocket issues any more.

Just my .02

Happy to pass on anymore information if it would help; it's a good cartridge but it has some pitfalls I think. If I were to do it again I would get a 300 Ackley.

Sooner04

 

[Wild_Bill]

Try and get RWS brass it is much better than Norma and will hold the pressure better. 375 0r 300 H&H brass can be formed easily.
Rebel Gun Works in QLD stock RWS and are the importers

Cheers Bill
Australia

 

[conquistador50]

Thanks guys,

I am currently testing resized 8mmRem Mag brass. I appreciate your comments and suggestions.