What powder in Lapua .338 match ammo?

[army-medic]

Evening all,

As I venture into .338 LM shooting I was hoping someone may know. I have assumed it will be a Viht powder since Nammo owns Lapua and Viht, but they could use something else I suppose.

Lapua match ammo for this calibre is very good but also very expensive. I’m hoping to try and replicate it and keep the costs down (relatively).

For some reason, on another forum someone decided to be very unhelpful when I asked this very question.

I have reloaded for about 15 years and know that manuals give a good recommendations but I was hoping to cut down on the experimentation and use a proven combo.

Thanks in

 

[Dr. Strangelove]

I have no reloading experience with the .338LM but I hope this is of help - https://www.bergerbullets.com/articles/brian-pearce-lapua-magnum.pdf

 

[aquarius11]

I have a Savage 112 in 338lap msg and asked a similar q on another forum after I loaded 100 rounds in different weights and tried different bullets, most of the data says max load is in the upper 80s and talking with the 50cal guys they were using 90-95g of powder.
Thus is the reply I got from over the pond, turns out the guy is a tip shooter and sponsored by Savage and lapua.
Hope it helps.

92 grains N570
Scenar 300’s
Lapua cases Fed Mag Match primer.

It will shoot one hole groups in your rifle
Many Savage 338’s have been TxE with that load.

 

[C h r i s]

N570 will burn out your barrel quickly, i use N165 in my 338.

 

[Treedave]

Used the now gone H1000, gone to RS70 and or Vhit 170 under 250 scenar in lapua brass.
Ping me a message if you want my numbers.
The idea of buying ammo to feed the beast gives me palpitations !!

 

[army-medic]

Thank you for all the responses. Very helpful.

 

[borbal]

The Vihtavuori reloading website...

Rifle reloading data | Handloading | Rifle calibers | Centerfire Rifle bullets | Reload your own ammo - Vihtavuori

Vihtavuori offers rifle reloading data for numerous calibers and bullets for match and hunting purposes. Never exceed maximum loads.

www.vihtavuori.com

... shows the sort of powders they recommend for various weights of bullet.

My P-Max app was created to help you answer this sort of question

You might like to read this article by David Tubb before you head off too far down that road.

 

[army-medic]

The Vihtavuori reloading website...

Rifle reloading data | Handloading | Rifle calibers | Centerfire Rifle bullets | Reload your own ammo - Vihtavuori

Vihtavuori offers rifle reloading data for numerous calibers and bullets for match and hunting purposes. Never exceed maximum loads.

www.vihtavuori.com

... shows the sort of powders they recommend for various weights of bullet.

My P-Max app was created to help you answer this sort of question

You might like to read this article by David Tubb before you head off too far down that road.

Thanks for that. I was aware of this data. If you look at 250gr for example it gives 5 different powder options.

I was rather hoping to cut down on experimentation. This info and what others have said above has cut it down to two powders. So I believe I’m closer to knowing what the factory ammo may comprise.
The PMax site is new to me though. That'll be very helpful.

 

[Laurie]

Viht developed N565 specifically for the 338LM with 250gn bullets, so there's a fair probability that Lapua uses a bulk version of that grade. N165 is definitely preferable for barrel life though as @CapePyla says. In fact, alongside Hodgdon H1000, N165 has a reputation as a 'cool-burner' that extends barrel life in 284 Win and short magnum match loads.

 

[borbal]

The PMax site is new to me though. That'll be very helpful.

Ideally, you want a powder that pretty much fills the case to get the maximum energy from the powder and get good shot-to-shot consistency. You should get good working pressures and the powder should be all-burnt just before the end of the barrel. Powders that are all-burnt too quickly need primer-popping pressures to get good muzzle velocities and are too fast. Powders that do not generate good working pressures even when you have a compressed load are generally not all-burnt before the bullet exits the barrel, and are too slow. Better to have too fast than too slow, as you don't want to be wasting powder by burning it outside the barrel, but filling the case with powders that are too fast will lead to dangerous pressures, so you need to work up the load with care.

Judged in this way, for the 250 grain bullet in a 338 Lap Mag., N165 would appear to be a little bit too fast and N170 a little bit too slow. H1000 has been mentioned, and this would seem to be the ideal powder with a burn rate that is just right. For the Chemie-Swiss powders, RS70 seems to be too fast and RS76 is a better balanced powder in these circumstances. The Chemie-Swiss powders are, of course, double base powders, so what you win with extra muzzle velocity you loose by reduced barrel life.

 

[palmer_mike]

Judged in this way, for the 250 grain bullet in a 338 Lap Mag., N165 would appear to be a little bit too fast and N170 a little bit too slow.

Then why not choose the powder that falls directly between these 2? (N565)

 

[borbal]

Then why not choose the powder that falls directly between these 2? (N565)

Why not indeed? Try it out using P-Max and see for yourself if it is a nicely balanced powder in these circumstances - or not... (Usable case capacity is about 100 grains H2O)

 

[palmer_mike]

Why not indeed? Try it out using P-Max and see for yourself if it is a nicely balanced powder in these circumstances - or not... (Usable case capacity is about 100 grains H2O)

Ok, so I’ve modelled it.
I’ll take your 100gr H2O (even though I’m not sure this is spot on?)

seems (according to P-Max) the the powder works pretty well.

alrhough as we are aware, modelling software is not infallible and real world results are possibly going to be quite different.

 

[borbal]

Ok, so I’ve modelled it.
I’ll take your 100gr H2O (even though I’m not sure this is spot on?)

It will be pretty close.

seems (according to P-Max) the the powder works pretty well.

I would agree...

alrhough as we are aware, modelling software is not infallible and real world results are possibly going to be quite different.

It depends what you are trying to get out of the modelling software.

If you are looking for accuracy within a few percent for maximum pressures, the approximations in P-Max, QuickLOAD and GRT mean that you will be disappointed. If you are looking for muzzle velocities within 2 to 3 percent, that should be achievable with these programs.

But if you are looking for the best balanced powder choice (good working pressure, good muzzle velocity) for a particular cartridge/bullet/barrel combination, then I would say that these programs will help you to make that choice to a high degree of certainty. They will also give you a reasonable idea of how the combination will perform, but with the qualifications given above.

It should be repeated that these programs should NOT take the place of a reloading manual from the relevant powder companies for estimating starting loads for maximum loads. Loads should be worked up using your particular rifle down on the range, not on a keyboard in front of a computer.

 

[army-medic]

Thanks chaps. This is the sort of response I was hoping for. I’ve been reloading for a fairly long time but you can always learn more.