Is this overpressure sign?

[ChuckSwagger]

I am new to the rifles reloading and after find a good spot on my 308W I started to do my 338 LM reloading development:
Rifle GAP Precision Hospitaller 28' Barrel and 9.75 groove.
Lapua Brass trimmed to 2.712.
Bullet Lapua Scenars 300gn. 1.002 ogive length
Shoulder 2.261.
Chamber OAL bullet ogive 3.034.
Jump 0.020 (3.014).
I tested two shots to zero my scope.
One with 91.6gn and 92 gn of the Retumbo Powder and got 2.815 and 2833 FPS.
Maybe on the 92gn the bolt lift was a little heavy, but I can't confirm since the rifle action isn't the slickest action.
The primers looks like ok, but the is some extractor marks on the brass...

The question is:
Are those marks an overpressure mark?
I am asking because I have red somewhere the 338LM should be pushed to 2.850-2.900 fps to optimize its potencial and I am afraid to push it unsafety.
Here is the brass pick:

 

[Supersubes]

What bullet are you shooting? Yes that’s excessive pressure you’re seeing.

 

[Huskydriver]

yep you are getting flow into your ejector..not crazy high but on the hot end...my 338LM barrel tops out at 91 gr of retumbo with 300gr bullets so you are about normal with that length tube.

 

[ChuckSwagger]

What bullet are you shooting? Yes that’s excessive pressure you’re seeing.

Sorry, I am using Lapua 300gn, 1.002 ogive length.

 

[ChuckSwagger]

yep you are getting flow into your ejector..not crazy high but on the hot end...my 338LM barrel tops out at 91 gr of retumbo with 300gr bullets so you are about normal with that length tube.

I have shot 88gn once to adapt the brass case to the the Hornady OAL gage and it was around 2.635 FPS.
Where should I start the 5 group load?
My rifle has 3 shots thru the barrel.

Thank you guys in advance.

 

[Supersubes]

Sorry, I am using Lapua 300gn, 1.002 ogive length.

Just back it off. How’d you come to those charge weights? I’ve owned two 338 Lapuas, and neither of them would go over 90 grains. It’s been a while but I recall them being in the 88-89 gr range. Take that with a grain of salt.

Thats with retumbo also.

 

[natdscott]

That is not always a sign of overpressure.

With Lapua head stamps, that is a sign of overpressure.

ETA: I REALLY dislike you starting on handloading with a Lapua Mag, and with only the internet as your loading buddy.

 

[Steel head]

Classic example of why primers don’t always tell you the truth.

 

[ChuckSwagger]

That is not always a sign of overpressure.

With Lapua head stamps, that is a sign of overpressure.

ETA: I REALLY dislike you starting on handloading with a Lapua Mag, and with only the internet as your loading buddy.

I started with the 308Win 3 months ago and found a good spot and reliability on the process so i started the 338LM load.
I live in a small town in Brazil and nobody close to me have a 338LM or is good on rifle reload so this forum and the internet are everything I have.

Thank you!

 

[ChuckSwagger]

Just back it off. How’d you come to those charge weights? I’ve owned two 338 Lapuas, and neither of them would go over 90 grains. It’s been a while but I recall them being in the 88-89 gr range. Take that with a grain of salt.

Thats with retumbo also.

I will try the 88-89 formula.
Thank you!

 

[Steel head]

I will try the 88-89 formula.
Thank you!

Unless you have a really long tube your lucky to bust 2800 with a 338 LM at a reasonable pressure.

The performance of the 300’s even at 2700 is excellent

 

[kriller134]

I've found this article to be very useful https://www.primalrights.com/library/articles/understanding-pressure

 

[ChuckSwagger]

When I was setting my Trim It 2, I had trimmed 10 cases with 2.708 and them I adjust to 2.712 lenght.
Is this diference insignificant?
The cases had 2.713-2.714 right out the box.

 

[Supersubes]

When I was setting my Trim It 2, I had trimmed 10 cases with 2.708 and them I adjust to 2.712 lenght.
Is this diference insignificant?
The cases had 2.713-2.714 right out the box.

Nope, move on.

Regarding charge weight, just start low and work up to it. This is no different than anything else. No need to trust the internet and just pick a narrow range. For me, I load three at each charge, start low, and work up. If I’m starting on a new barrel in a very familiar cartridge, then I’ll pick a narrow window, but still working up. Another thing. The lapua is a huge case, use half or full grain increments.

 

[TheGerman]

As said, ejector mark.

Not the end of the world unless you're getting other things like blown/very flat primers, excessive recoil or a heavy/stuck bolt. Sounds like 92.0 would be too high.

My only warning would be to watch it when shooting in higher temps depending on the powder.

 

[db2000]

That's a big load to be experimenting with
Try Quickload software to help you estimate chamber pressures.