.338 load data

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Cutch

Well-Known Member
I had an RFD assess my load on that rifle and then make me my .338 ammo when I bought my rifle as I was far too busy at the time. When I picked it up they handed me my newly built ammo and told me the load it was.

I wasn't really happy with that as I thought I was getting the data that they shot and assessed to come to the conclusion that we needed X amount of grains etc.

I am now doing it myself and loading my own. I was going to load either 3 or 5 at each grains and increase by 0.2 each set of 3 or 5 until I get my desired node?

Upon check the Vihtavuori website though it looks like the load Maximum for my setup is 84.7grains and my RFD has made my ammo at 96grains!

Does this sound correct? Seems awfully high compared to the max on the site.

My rounds are .338 Lapua Magnum brass, Federal GM215M large primers, Vihtavuori N165 powder, Hornady 285 ELD Match

Any advice would be greatly appreciated
 
Have you pulled one and weighted the powder charge, just in case they got it wrong? That's too big an error to risk shooting that ammunition without a basic check.
Also, what powder did THEY use, or is it the same as listed for your rounds?

Regards

Mark
 
I have a tub of RS80 there that may have been used (this was years ago) what would the difference be in pressure then? Maybe I am remembering incorrectly, I was sure it was Vihtavuori that they used but it could possibly be RS80?

They gave me all the boxes etc of the stuff they used. I effectively bought all the cases powder etc, they built the rounds for me and gave me everything that was left over.

I weighed the built rounds and they are exactly the same with 96 grains...

the tub of RS80 is full so i didn't think it had been used but maybe that was the second tub because 100 ends should have used quite alot of powder??
 
I can't offer any advice but without any thought putting that 96grain load and your other info into quickload gives over 104k psi which seems a lot! Slightly compressed too.

Screenshot 2025-03-18 102941.webp
 
94 grains = max without warning on RS 80.
1742297937848.webp
Pull a bullet and compare the powder in that case under a 10x magnifying glass.
I would pull them all, dump the powder and start again to really be on the safe side.
 
I need to check back through my data but my only load I can see with N165 was with 250gr lock base. I loaded 84 to 88.5 grains. 96 gr seems high.

Is it definitely N165? N170 would be nearer that load.
 
In view of the uncertainties you have which even include what powder was used, it would be sensible to disregard anything you were told or think you know regarding that ammunition (plus disassemble any remaining) and start from fresh using the published data from the relevant powder or bullet manufacturer.
 
I've actually used 65 rounds out of the 100 that were made. The cases don't show any signs of over pressure. The loads are not compressed, I can rattle the powder in the built cartridges?

Yes I think it would be safer to completely start again. I'll pull the bullets and make up my new batches to compare.
 
Cutch said:
I've actually used 65 rounds out of the 100 that were made. The cases don't show any signs of over pressure. The loads are not compressed, I can rattle the powder in the built cartridges?

Yes I think it would be safer to completely start again. I'll pull the bullets and make up my new batches to compare.
Click to expand...

I’d suggest it’s not 96grs. If they shoot well and no signs of pressure then go ahead and shoot the rest. Once all gone start your loading from scratch using published data.
 
Jagged77 said:
I need to check back through my data but my only load I can see with N165 was with 250gr lock base. I loaded 84 to 88.5 grains. 96 gr seems high.

Is it definitely N165? N170 would be nearer that load.
Click to expand...
It's RS80, I've found the sticker he wrote the details of load on.

This is the details on the batch sticker.

.338 Lapua Magnum brass, Federal GM215M large primers, RS80 powder, Hornady 285 ELD Match

Alot better on the pressure calculation
 
Cutch said:
It's RS80, I've found the sticker he wrote the details of load on.

This is the details on the batch sticker.

.338 Lapua Magnum brass, Federal GM215M large primers, RS80 powder, Hornady 285 ELD Match

Alot better on the pressure calculation
Click to expand...

That’s a relief. 96gr is under the max load for 300gr Sierra MK so all good for 285’s. Happy reloading
 
Cutch said:
It's RS80, I've found the sticker he wrote the details of load on.

This is the details on the batch sticker.

.338 Lapua Magnum brass, Federal GM215M large primers, RS80 powder, Hornady 285 ELD Match

Alot better on the pressure calculation
Click to expand...

1742308198833.png

From GRT. Max pressure stated is just under 61k PSI.

Regards

Mark
 
Thanks for all your help guys.

Made up 50 rnds of varying weights and have booked range time to check the nodes.

Appreciate it 👍
 
Yea theres something not right at all with GRT with 338 with the next bullet it has data for 165 in.... I put in data straight from Hornadays loading manual 10th edition.

250 Gr BTHP Hornady Match
93.7 Gr N165 Absolute Max ~ 2800 FPS yields 70K PSI.

Not sure whats up with it but thats super odd.
 
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