How much should I decrease my charge when going from Lapua to Alpha?

[1bamashooter]

Since I lost all my Lapua brass I decided to try Alpha and see how it works before I get DJs to hydroform me some more Lapua. I was loading 32.0gr of varget in my Lapua brass with a MV of 3000fps how low should I go with a starting load in the Alpha brass?

 

[1shot]

Check the H2O weight of both, then reduce by the percentage of difference if the Alpha is less.

Lloyd

 

[1bamashooter]

Check the H2O weight of both, then reduce by the percentage of difference if the Alpha is less.

Lloyd

I don't have any of the lapua brass it was lost in a house fire

 

[KMart]

I am shooting some of the Alpha OCD brass in a 6 dasher right now. I have been pleased with it and it seems to be preforming as well as the Lapua brass with very similar powder charges.
I did, however, shoot the OCD brass one time with powder charges a couple of grains lighter than max loads,

If you stop and think about fireforming Lapua brass, you fire them once or twice with lighter charges before you get the shoulder set correctly. Maybe that is key to the longevity of the Lapua brass. I am shooting a pretty healthy charge of H4895 and 103 grain bullet in both Cases

I did shoot some of the pre OCD brass and Peterson and I wasn't pleased with them on velocity and pressure.

I think you will like the OCD brass.

 

[RegionRat]

Maybe it is my chamber specs, but I don't have a difference between Lapua and Alpha OCD.
I use Varget, CCI450, Berger 105 Hybrids, or Sierra 107s with seating forces of roughly 35 to 40 lbs and jump.
I can say this did surprise me, and I can't predict what happens in the next chambers. YMMV

 

[Bill K]

Same as you should with a change in any brass, from a given load. at least 10 %, by most manuals. Then work back up, slowly.

 

[1bamashooter]

Thanks for the replies fellas I was just wanting some input from people that switched so I could possibly not use as many supplies getting a new load worked up. Thanks again!

 

[JFrank]

Some one posted this a couple weeks ago that I thought was interesting and perhaps helpful to the OP

 

[GlennK]

Same as you should with a change in any brass, from a given load. at least 10 %, by most manuals. Then work back up, slowly.

This is pretty solid advice. It will most likely be about a grain to a grain and a half less for charge depending on node, but always go with safety first.

 

[Bill Norris]

This is pretty solid advice. It will most likely be about a grain to a grain and a half less for charge depending on node, but always go with safety first.

There was a 10 gr. weight difference between my 100 pc. lot of 6mmBR Lapua and Peterson brass. I reduced the start loads by one grain and all was well with pressure signs.