Optimal velocity

[johngarnett]

My usage is TR and FTR. Calibre is .308. Using 155gr Lapua's. I've just changed to RS52 and wonder what velocity I should be looking to achieve for the likes of long range ie 1000yds stability please?

I have found a good grouping load at 45.8gr with velocity of 3020fps. I have also found 45.0grs accurate but velocity is 2950fps. What is the magic long range velocity?

How much more barrel wear am I likely to see with RS52 rather than RS50 under FTR conditions and these higher velocities?

I hope this makes sense! Thank you for reading!

JohnG

[Re-Pete]

I use 46.3gns of RS52, which gives 3060 fps with 155 Lapua Scenars. Barrel is 30" 1:11 twist.

I have pushed these to 3140 fps using RS 52, but 3060 gives me the best group.

According to Litz, an MV of 3060 fps drops to 1338 at 1000 yds with the 155 Lapua, so it's still a tad over  mach 1.

Pete

[johngarnett]

Thank you Pete

JohnG

[Re-Pete]

As far as barrel wear is concerned, I have a 6BR with a 30" 8 twist Lothar-Walther barrel that's been round the galaxy a couple of times. It was very well used when I bought it a few years ago, and has had at least 3000 rounds through it since, using a stiff (for 6BR) load of RS52, with 105 Scenars emerging at 2950 fps.

It will still shoot 1/2 MOA if there's no wind and I can hold it still enough. Over that time, there has been a bit of throat erosion, say 0.5-0.75mm, but nothing unexpected, no excessive fire cracking. Barrels, like clutches, are consumables, after all...................

My 308 has had a couple of thousand rounds through it using RS52, and the bore still looks like it did the day Mik Mak re-barrelled it.

Re-Pete

 

[johngarnett]

Thank you Re Pete

JohnG