338 Lapua, 95gr. Retumbo??

[Duff]

been looking at some load data for .338 lapua mag for 300gr berger OTM. the berger website says the max load for retumbo is 89.5 gr. which puts out around 2680 fps. one of the loads i was looking at today says that he put 95 gr. of retumbo that got him around 2925 fps. Now Bergers site says that 89.5 grs is a 107% fill. so my question is first of all is this even safe?? he says he hasn't gotten any pressure signs but a full 5.5 grs over max recommended fill. some extra velocity would be nice but not at the cost of a 3 grand+ rifle and quite possibly life and limb.

 

[Sonic Crack]

every barrel is different, work up your loads slow, load manuals are good starting points but not necessarily law, your milage may vary

 

[diverdon]

Take Aim at Rifle Reloading Data | Hodgdon Reloading

Hodgdon gives the max load as 94 grains and has the compression C after the 94. That is for the 300 gr Sierra HPBT and gives 2,654 fps.
[h=3][/h]

 

[zackm]

I have a savage 110 fcp and have loaded to 94.0 gr but bolt lift was heavy and i had psi signs flat primers ect. I have heard of people using 95 gr. but that pretty hot. With 89.3 gr retumbo and 300 gr berger otm i get 2710 out of my savage.

I also have been trying wc867 powder in the 338 lapua and it has been working very well. I use 105.7 gr of wc867 behind a berger 300 gr otm bullets and use lapua brass. I get 2870 out of that with my savage and not psi signs but start with that around 101 gr and work up. I also hit a nice node with that powder and bullet at 102.3 gr wc867 300 gr berger and they are coming out at 2780 fps. But back to retumbo you will find that 89.3 gr should shoot well for you be easy on brass.

 

[NICETRY]

Yeah I have tested in my Savage up to 94 grains. With one lot of powder I was seeing pressure signs past 92 gr. Settled on 92 and it got me an average of 2750fps. With a different lot the same 92 gr was just over 2800fps with very heavy bolt lift. That lot I settled on a load of 90.6 gr that averaged 2730fps. I have not noticed any compressed powder with the OAL length I use with 300gr bergers but at 92 gr I did have compression. I would start low and work your way up. But I would say what Berger has in the manual is fairly safe.

 

[jkonzal]

If you can find some, try RL-25. With a 30" tube, I'm getting 2951 with 91gr under a 300gr SMK.

 

[kyhuntclub]

I run 90 grains with 300 gr SMK touching the rifling at 2780 fps. In my rifle I had heavy bolt lift at 91.2 grains.

 

[Wally Pinkerton]

I run 90 grains with 300 gr SMK touching the rifling at 2780 fps. In my rifle I had heavy bolt lift at 91.2 grains.

Same for me. 90g is the sweet spot for my brother and I.

 

[kyhuntclub]

I actually couldnt tell any difference in accuarcy between 89-91 grains. At 91.2 the bolt got heavy and i just settled at 90 grains. From 89-90 grains they all shot under a 1/2 minute.

 

[ZombieSlayer]

been looking at some load data for .338 lapua mag for 300gr berger OTM. the berger website says the max load for retumbo is 89.5 gr. which puts out around 2680 fps. one of the loads i was looking at today says that he put 95 gr. of retumbo that got him around 2925 fps. Now Bergers site says that 89.5 grs is a 107% fill. so my question is first of all is this even safe?? he says he hasn't gotten any pressure signs but a full 5.5 grs over max recommended fill. some extra velocity would be nice but not at the cost of a 3 grand+ rifle and quite possibly life and limb.

Things you need to consider as individual variables off the information given even with everything else constant.
OAL.
Distance to lands/freebore
Primer.
Brass capacity.
Scale accuracy.
And also bore.

Combine the extreme of all together and their data might be bad news for you.

For example freebore. Same load another rifle might have 40 thou jump. Your rifle 20 thou jammed. Expect a significant difference max pressure increase not in your favour.

Shorten OAL for your shorter freebore same load both 20thou jump again expect higher pressure on the shorter of the 2 all else being equal.

Same with actual bore diameter. His might be .3385 yours might be .3375. Again expect more pressure on your rifle.

Now combine your tight bore, shorter freebore (jammed or shortened OAL). Maybe add a different batch of brass with less volume and throw in a hotter primer and a poorly calibrated scale and you can probably see where I'm going and where you shouldn't. Or it could be as simple as someone else left the lid off the powder tub for a few weeks and forgot about it.

And that's with most handloaders not having the equipment to measure actual pressure and just glancing at the primer and gauging bolt lift and likely not throwing a micrometer on the case either.

Blow up your rifle dangerous, probably not but you won't be doing it any favours. A blown primer and some bolt face erosion could be likely. At the very least a wasted drive to your shooting venue and the time to pull and load some more up when you get home.

Load manuals are a guide for a perfect world. Manuals are numerous. Not so sure about perfect worlds.

 

[300 jarret]

In my Barrett 98B 94 grains of H1000 under a 250 grain Lapua Scenar delivers 1/3 moa out to 800 yds.

 

[Duff]

thanks for the help guys!

 

[nso123]

In my rifle with a 28" Krieger, I average 2655fps with 89.3gr of Retumbo and a 300gr SMK seated .010 from the lands.

 

[Jeffvn]

My 338Lm ran on 88+ gr. of H1000 (case held roughly 108 gr. H2O) under a 300 smk;

My 338LM Improved (124 gr. H2O) runs on 100 gr. Retumbo, 105.5 RL-33 under a 300 SMK or 300 Scenar...

there is a big difference in case capacity between the improved 338LM and the regular 338LM, plus my338 LM Improved is long-throated for single feed only... lots of case capacity for powder.

Jeffvn

 

[skin]

Has anyone used WC867 powder in 338 Lapua? Found a good deal on GB (38/pound) and am just getting into the Lapua, planned on using H1000 but it's really up there in price - 95/pound. Seller states the WC867 is similar to retumbo and H1000. thanks in advance.
Mike

 

[secondofangle2]

“Pennywise and pound foolish“ is a saying that comes to mind. You’re gonna have a lot of money in the case a lot of money in your gun barrel a lot of money in a primer and a projectile and I wouldn’t skimp on the last component to save $.30 around by using a powder with little available data and uncertain to work well