308 155 gr SMK load

[Dustyman]

Thanks I think I was being a bit conservative on powder , ill push it up and see if I get another node , , Ian

[Maggot]

I am getting 3065 FPS (through a 30" FTR barrel with a barnard action) with the 2156.

Set 16 Thou off

47.3 of N140. Lapua Palma brass and CCI BR4 primers.

I was using 47.8gr but in reality there was little gained.

Oddly enough, I have found that my rifle seems to shoot better with a full case.

I also find the groups tighten up fairly predictably at about a .5-.6gr interval.

The 2156 is a nice bullet, particularly for the price, considering it is pointed etc etc.

This will shoot about .3moa, but that was measured at 200.

[GazMorris]

47.3 of N140. Lapua Palma brass and CCI BR4 primers.

That's a fairly, um, stiff load you've got there (although if you're using the small flash-hole brass that might explain it.) Ever get any pressure signs?

Gaz

[ovenpaa]

CCI BR4 primers are small rifle so this would be with Palma brass.

One of the characteristics of the small primer (Palma) brass is a reduction in pressure and MV with like for like powder charges versus the normal Lapua .308 Win brass, this would equate to around .5 grains ish so a 47.3 load in Palma is going to give similar results to 46.8 grains in normal brass.

Also the Palma brass does cope with pressures slightly better however at around the GBP25/100 more it is quite an investment.

[rox]

One of the characteristics of the small primer (Palma) brass is a reduction in pressure and MV with like for like powder charges versus the normal Lapua .308 Win brass, this would equate to around .5 grains ish so a 47.3 load in Palma is going to give similar results to 47.8 grains in normal brass.

Shouldn't that be "47.3 load in Palma is going to give similar results to 46.8 grains in normal brass"?

Surely if a like-for-like charge in Palma brass results in lower pressure/MV, then a larger charge is required in Palma brass to achieve the same performance?

..

[ovenpaa]

Rox, My typo, corrected now.

Palma gives lower MV's and pressures for like loads with Win .308 so yes a larger charge is required to give the same performance. The .5 grains is an approximation so it is very important to not assume you can just shove another half grain in the case if it is Palma...

[Maggot]

47.3 of N140. Lapua Palma brass and CCI BR4 primers.

That's a fairly, um, stiff load you've got there (although if you're using the small flash-hole brass that might explain it.) Ever get any pressure signs?

Gaz

No, even at the higher loads, but yes, it is palma brass

Its conservative compared with some.

No, no blown primers in hot weather either, it works. But I don't chamber until ready to go and the ammo is kept covered.

I had one extruded primer early in load testing (quite low down the scale) and still have it as it was a CCI and I suspect the material was over annealed, it only ever happened the once.

The Palma brass is used a lot by the F/TR guys as it will do the job

It does seem that I have quite a quick (30" 3 groove Lilja Palma) barrel hence the velocities.