How much to reduce loads for Lapua brass?

[mattri]

Have been using Win brass for the 20 Practical.

Going to try some Lapua brass.

Lapua brass is known to be thicker, with less interior volume than other brands of brass.

What is a good rule of thumb to reduce loads by?

Thanks, Matt.

 

[shooter63]

matt i dont think you need to worry about reducing your load going from win to lapau alan.

 

[mattri]

Thanks for the reply. I've read so much about pressure spikest etc when using load data from other brands of brass with Lapua brass, is this not always the case?

 

[DennisH]

The only issue I have ever heard is Lapua will hold a fraction less powder than Win or Remmy brass, and this will only affect those who are at their max load, therefore their load becomes compressed. Were talking maybe a grain or less powder.

Otherwise, I use Rem, Win, and Lapua brass and don't worry about anything!

 

[artbosco]

Have been using Win brass for the 20 Practical. Going to try some Lapua brass. What is a good rule of thumb to reduce loads by?

Printed on the side of the container, at least for Hodgdon's, most powder manufacturers recommend reducing a load by 10%, then working up the new load.

 

[jasonf]

I switched from Win to Lapua in a 223 and worked up my loads from scratch, ended up with exactly the same load. The 223 page on this site has volume data which shows Win and Lap as being identical. If you loads aren't at max in the Win brass, I suggest dropping by 5%.

 

[mattri]

Thanks for all of the good tips. I'm at 23.1gr of H4198, a little over listed max for a comparable load in .223 so the plan is to start at 22.5 and go from there.

 

[KevinThomas]

mattri,

As the others have already suggested, there's no need to reduce loads in the Lapua brass anymore than you would in changing any component before working back up. Our internal capacity is very close to those of most US commerical and LC brass, and the ultimate loading data is likely to be very similar to what you develop with other brands.

 

[mattri]

Thanks for the reply, guess you don't get more official than that.

 

[Hondo64d]

For me, with my .260 Rem, Lapua .243 brass took about 1gr less powder to get the same velocities with Remington brass.

John

 

[jasonf]

Good call Dave. I was assuming that the OP was using new Lapua cases.

 

[markm87]

I switched from Win to Lapua in a 223 and worked up my loads from scratch, ended up with exactly the same load. The 223 page on this site has volume data which shows Win and Lap as being identical. If you loads aren't at max in the Win brass, I suggest dropping by 5%.

Yeah.... most 223 brass volume variance is negligible.

.308 on the other hand can be significant.