Load data 338 Lapua?

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mdblough

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Hi All,
I am about to embark on my first round of reloading for 338 Lapua. I have all the equipment I require, brass (lapua), primers (federal 215), and bullets (300 grain lapua), but am struggling with which powder to get, how much to load, and C.O.A.L. I have checked different sites and for the 338 lapua there a variety of powders for a 300grain 338 bullet. I was trying to find someone that has optimized loads for my rifle (Blaser/Sig Tac2) but have only found limited information.

One gentlemen used Vihtavuori N170 powder (88.4gr). The Vihtavuori website recomends 75.6gr to start, and 88.6 max. I was wondering if I should start with the minimum load, make 5 rounds, then increase the load, make another 5 rounds, and so on, until I hit the maximum load. I apologize if this sounds naive - but as a newby I am kinda uncertain where to start with the loads.

Also - how important is COAL for first loads. Is this something I should optimize later on?

Thanks very much for any suggestions. I am fairly tech savvy, so am certain with a bit if guidance I can figure this out.

Cheers!
Mike
 
FWIW - I found 7828 to be the best in my system. Tried Retumbo and H-1000 but the rifle did not like them. COAL is important for fine tuning, but get your base load figured out and grouping first. I am currently running 7828 under 300gr Lapua senars. Barrel is a custom "Jury" at a 1:9twist. I don't like to post gr of powder used as each system is different. I can PM the weight if you really want to know, but don't use it as a starting point. Keep your brass consistent by sorting to brand; trimmed and cleaned. If I do my part, they will clover leaf at 200yds. Its a genuine thrill.
 
Thanks, Bonemaker! So for optimizing powder load, would I start with the minimum (i.e. 75.6 gr), assemble 5 rounds, then increase the load by a couple gr, make another 5 rounds, and so on, until I hit maximum load (i.e. 88.6gr) then test out the accuracy of loads and go with the one that gives the best results? Maybe this is intuitive, I just want to make sure I do it right! The barrel on my Tac2 is 27inch with 1/10 twist.
 
I hate to ask but is .338 Lapua the first rifle caliber you are reloading for?
If it is then there are many steps you will need to master.
As for charge weight Google Dan Newberry OCW load development system.
I wish you all the best of luck.
 
A chronograph helps a lot and access to a long enough range. 200-300M or more when it comes to checking accuracy/elevation.
Your rifle and combination of components may not allow it to reach max book load, just as there are times where its possible go a bit higher but it has to be done right.

I usually load only 2 bullets of each increment(I do it in .3gr for 308) for a .338 I'd likely try it in .5gr increments.
Then I set up at the range with the chrony and see where I start to see pressure signs on the primer/brass and what the speed looks like, pull any that were above that and likely unsafe to fire. Saves a lot of range trips when its 1hr each way. Then I pick a powder weight range that looks safe for the weather I'll be doing most of my shooting in and test it a bit more for accuracy. Hot weather will change things and be very careful if there's any rain as it will spike pressure/wreck stuff.
 
I use a ladder test , found it works very well and saves on components.I cannot type right now what all is involved but you basically do your test loads in single increments ie) 88.5,89,89.5,90, etc.......fire all shot at the same point at 200-300 yards to start with , find your "clusters" of impacts and this shows you sweet spots in the harmonics of your barrel and fine tune from there.Since you are doing .338LM you will want to do some fine tuning and testing at much longer ranges as this chambering is more suited for extreme range.

Chronograph is nice but not necessary if you are reaching for accuracy with this chambering as it does possess all the punch you will need.

As for charge weights my best recommendation is to use the guide at Winchester/IMR/Hodgdon , you can select you chambering , bullet weight and then see which powders are recommended and go from there, I also will not give out my powder charges as each rifle is different and MUST have a load worked up safely for that one rifle, there is no shortcut to a magic load.

My rifle prefers Retumbo with 300gr SMK. My last test groups at 500 were within 1/4 the page of an 8.5 x 11 piece of paper , 2.8" or so inches I believe, I may play with seating depth after I sight in for 1000.
 
I have had realy good results with H4831.... but its a ##### to meter, my redding does a good job but I still have to drop the last bit with a trickler.

I haven't tried the short cut 4831sc yet


starting load .5 grain increments, keep shooting until either you hit pressure signs, or the groups start to widen out narrow it down... then fine tune in .2 up and down from the best (.5) that you shot.

COAL is inportant depending on the bullets you use. manufactures usually recommend a seat from land depth... barnes for example says 5 though off the lands is ideal...and after some screwing around... that pretty much runs true.

There is the proper way to do it... and the poor mans way, which honestly works almost as good as the $200 some odd dollars in tools and only requires the sacrifice of one of your cases lol.

Step one:

first you need to figure out your land seating depth... you can use a MIC... or... you can cut two vertical wedges out of your cases neck so that you can slide a projectile in and out by hand... it should still be a little stiff though so don't cut to much.

Stick the projectile in the case sitting out extra far and chamber it.... then carfully pull it out.... that bullet is now at the length to sit on the lands.

Step two

Measure the COAL, you should use a precision Mic on this as well... but.... you can measure it with a set of calibers, not perfect but pretty damn close.

Now you know how long the COAL has to be to seat on the lands

Adjust the coal of your reloaded rounds (projectile seating depth) for either a jump or a jam as desired.



A word of advice

do not test MOA on .338 LM under 200m infact do it at 300m if you can

the rounds do not settle down till at least 200m... they actually do a corkscrew spiral in the air

the only thing worth test for at 100m on .338 LM is muzzle velocity and the "am I hitting paper" site in.
 
I doubt the laws of physics change much because its called a 338 lapua mag! :) but you never know.
 
LordEvilPepper said:
starting load .5 grain increments, keep shooting until either you hit pressure signs, or the groups start to widen out narrow it down... then fine tune in .2 up and down from the best (.5) that you shot.

COAL is inportant depending on the bullets you use. manufactures usually recommend a seat from land depth... barnes for example says 5 though off the lands is ideal...and after some screwing around... that pretty much runs true.

There is the proper way to do it... and the poor mans way, which honestly works almost as good as the $200 some odd dollars in tools and only requires the sacrifice of one of your cases lol.

Step one:

first you need to figure out your land seating depth... you can use a MIC... or... you can cut two vertical wedges out of your cases neck so that you can slide a projectile in and out by hand... it should still be a little stiff though so don't cut to much.

Stick the projectile in the case sitting out extra far and chamber it.... then carfully pull it out.... that bullet is now at the length to sit on the lands.

Step two

Measure the COAL, you should use a precision Mic on this as well... but.... you can measure it with a set of calibers, not perfect but pretty damn close.

Now you know how long the COAL has to be to seat on the lands

Adjust the coal of your reloaded rounds (projectile seating depth) for either a jump or a jam as desired.



A word of advice

do not test MOA on .338 LM under 200m infact do it at 300m if you can

the rounds do not settle down till at least 200m... they actually do a corkscrew spiral in the air

the only thing worth test for at 100m on .338 LM is muzzle velocity and the "am I hitting paper" site in.
Click to expand...

This ^^^
Don't waste your time shooting less than 200 yards.
Use a comparator to measure your COAL because if you go to the bullet tip you'll be chasing it forever due to differences in bullets. You wouldn't think there would be much difference with match bullets but there is. I made one that slips onto my calipers out of a 300 Blackout brass, the 30 cal neck works nicely with the 338 bullet.
I've used Retumbo, H1000, and I'm currently using US869 but have been thinking of trying something a little more temp stable.

Good luck
 
hawk-i said:
I doubt the laws of physics change much because its called a 338 lapua mag! :) but you never know.
Click to expand...

what does that even mean?

are you talking about the corkscrewing?

even a lot of .308 bullets are not recommended for precision under 200 yards because of the cork screwing effect... burger put out a video showing what there rounds do up to about 170 yards.

When I was shooting burger 168... 100 meters couldn't get them under 1.5 inches.... took the same load out to 200m .5 inch group,
 
Thanks everyone for your responses! This has been tremendously helpful. To be honest it is all a bit intimidating, but I'll proceed slowly and cautiously. Cheers!
 
mdblough said:
Thanks everyone for your responses! This has been tremendously helpful. To be honest it is all a bit intimidating, but I'll proceed slowly and cautiously. Cheers!
Click to expand...

It's really no different than reloading a 308 win, it's just bigger. In some ways it may actually be easier since there are a lot less projectile and powder options and as long as you take your time and use published reload data from a reputable source you really can't go wrong.
Stick to 250-300gr projectiles and don't try to use powder that is not commonly used in the cartridge.
 
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