Questions on H1000 and 338 Lapua Mag

[wadebrown]

I finished the build on my 338 Lapua Mag yesterday so I went to Hodgdon's site and looked at the range of charges for H1000 under a 300 grain bullet, I am starting with 300 g Scenars. The range of loads on the site was 83 grains to 92 grains with a max velocity of 2590 fps. I have jugs of H1000 and Retumbo to see which works better in the rig, flipped a coin and decided H1000 was the one to start with.

At the range today the primers started to flatten at 87 g and 88.5 g H1000 seemed like a max load due to the primer condition. The velocity at 88.5 grains of H1000 was about 2675 fps as measured with CED chronograph with consistent light on it.

What surprised me was that what I felt was a maximum was 3.5 grains below the data book maximum. Is this normal for recent batches of H1000?

The build specs are:
- Defiance action
- Brux 1-9.5" twist 28" long from breech to crown with a 4 port Muscle muzzle brake
- XLR Evolution HD chasssis
- Timney trigger

I have reloaded for over 35 years but this is my first time reloading for the 338 LM and looking for some wisdom with this caliber.

Thanks

wade

 

[BobinNC]

Re: Questions on H1000 and 338 Lapua Mag

Wade,

Your using a 300 grain Lapua, Hodgdon used a 300 gr SMK.

Your powder lot is not the same as Hodgdon.

Your barrel and chamber are not the same as Hodgdon.

Your velocity was 85 FPS OVER Hodgdon with 3.5 grains LESS powder.

How does your COAL compare to Hodgdon, and how far are you off the lands.

Primers are a poor indicator of MAX pressure.

And finally MAX loads are only a guide and not written on stone tablets.

If your accuracy is there, and velocity looks good, and using 3.5 grains less powder to achieve it, sounds like a win to me......

 

[psinclair]

Re: Questions on H1000 and 338 Lapua Mag

Was your bolt lift stiff? Ejector mark?.....I agree with Bob on the flat primers being a poor pressure indicater....especially with the .338LM.

I just worked up a dynamite load for my GAP .338LM with H1000 and 300gr Berger VLD's. I found 91.0grs was the most accurate dose. And jumping them 10 thou. MV is 2780fps through a 28" 1-9.7" Bartlein 5R MTU. Lapua brass, Federal 215 Mag Match primers.

FWIW, I also tested Retumbo. It was a little faster, but not as tight.

 

[dyoung]

Re: Questions on H1000 and 338 Lapua Mag

Wade
I had good luck with the 300 Scenars using 91.5 grs of Retumbo @2780...its a pretty hot load so work your way up.

 

[mram10]

Re: Questions on H1000 and 338 Lapua Mag

The newer H1000 is hotter than that of the past according to many. I found that with my 300 rum and edge. Search and you will find many having a problem with H1000 loads being much lower than in the past.

 

[Jeffvn]

Re: Questions on H1000 and 338 Lapua Mag

+1 on the hotter H1000.

I'm using just over 89 grains under a 300smk. 90 grains gave me sticky bolt, flat and cratered primers, and ejector marks.

I have also heard the same cautionary statements concerning newer lots of Retumbo.

JeffVN

 

[mram10]

Re: Questions on H1000 and 338 Lapua Mag

Jeff,
I just finished my load development (338 edge)...again for this new stuff and I am shooting 89.2gr of h1000 out of a 30" brux. Very accurate, but I am very curious to see how fast it shoots. Glad to see I'm not alone in the very low charge weights.