338 Berger OTM 300 gr seating depth

[el matador]

I'm going to try these in my 338-378. My question for all of you experts is about the seating depth as it relates to the very long nose of these bullets. The Berger manual says 3.750" OAL and every load I can find on the forums has a similar length, mostly 3.760-3.800". Well the case length is 2.913" and the nose of the bullet is 1.000". This means that if I seat to the recommended length my ogive will be over .100" down inside the neck. I've never seated that deep and it seems strange. I'm probably just going to single feed these so mag fitment won't be an issue.

 

[pyroducksx3]

Get one of these
Hornady Manufacturing Company :: Reloading :: Metallic Reloading :: Tools & Gauges :: Lock-N-Load Gauges-Formerly Stoney Point :: OAL Gauges & Modified Cases :: OAL Gauges :: Lock-N-Load® OAL Gauge Straight
then one of these, you will need a custom modified case as I don't believe they make a 338-378 weatherby Hornady Manufacturing Company :: Reloading :: Metallic Reloading :: Tools & Gauges :: Lock-N-Load Gauges-Formerly Stoney Point :: OAL Gauges & Modified Cases :: Modified Cases
follow the direction measure with calibers and the appropriate 338 collet and you will know the seating depth for your rifle for the ogive to touch the lands

 

[mitch260]

The nose is actually .930." But I agree, If you want to use them, just go single shot and seat them out close to the lands.

 

[el matador]

Thanks for the input guys. I've got the tools for measuring ogive to lands but in this rifle that's kind of moot. Weatherby makes them with .3600" of freebore to keep pressures down so seating close to the lands isn't very practical. I'll probably start around 3.820 or so to keep the ogive out of the neck and adjust from there if needed. I just found it odd that people are seating these so deep.

 

[pyroducksx3]

It's not really moot point. If you are supposed to have.36 of free bore you measure to the lands then subtract .36 and you have your starting point. You have to know where your lands are to know you have freebore.

 

[longrangehunterII]

Thanks for the input guys. I've got the tools for measuring ogive to lands but in this rifle that's kind of moot. Weatherby makes them with .3600" of freebore to keep pressures down so seating close to the lands isn't very practical. I'll probably start around 3.820 or so to keep the ogive out of the neck and adjust from there if needed. I just found it odd that people are seating these so deep.

You can seat them just off the lands but you'll need to reduce the powder charge and run them at a lower velocity.
The ogive is the leading curved edge from the tip up to the bearing surface of the bullet....lightbulb This is what you'll want to measure off of to the lands(rifling), if you're not sure where the loaded round is in relationship to the lands, make sure a loaded round when drop down into the chamber will fall back out!!! If not, the bullet could be seated out too far and contacting the lands, this in a Wby. with a full power load will be dangerously hot load!!!

Make sure you understand what you're doing and GET a chronograph and read up on this subject in the reloading manual. You need to understand bullet terminology and the difference between the Boat Tail, bearing surface, and the ogive.

Pyroduck's answer will allow you to run your weatherby at factory full power loads when they're seated .3600" off the lands.

 

[el matador]

Sorry if I'm coming across as a noob here, I've just never encountered data that recommends seating the ogive down into the neck. I've been loading for over 20 years and tens of thousands of rounds. I'm very familiar with the different parts of a rifle bullet, having designed and built my own at one point. I also understand the convention of using the lands as a datum point since most rifles have a relatively short freebore. That's where I measure from on my other rifles. I don't plan on coming within even .200 of the lands with this gun which is why I feel that distance is moot. I'm just going to use a different datum point, such as cartridge base to ogive or COAL instead.

 

[madman]

I'm going to try these in my 338-378. My question for all of you experts is about the seating depth as it relates to the very long nose of these bullets. The Berger manual says 3.750" OAL and every load I can find on the forums has a similar length, mostly 3.760-3.800". Well the case length is 2.913" and the nose of the bullet is 1.000". This means that if I seat to the recommended length my ogive will be over .100" down inside the neck. I've never seated that deep and it seems strange. I'm probably just going to single feed these so mag fitment won't be an issue.

I'm loading them to 4.10 OAL. It measures 3.253 at the ogive. Won't fit in the magazine, but that's no issue for me. Shoots consistently .5MOA or less.

--md

 

[el matador]

I'm loading them to 4.10 OAL. It measures 3.253 at the ogive. Won't fit in the magazine, but that's no issue for me. Shoots consistently .5MOA or less.

--md

Good info madman, thanks for posting. Can't argue with that kind of accuracy! What kind of velocity are you getting at that length?

 

[madman]

Good info madman, thanks for posting. Can't argue with that kind of accuracy! What kind of velocity are you getting at that length?

Yes, the accuracy is great. It has taken a considerable amount of time and effort to get a load working in this rifle.

My velocity is a best guess at this point. It's right at about 2850, but due to a chronograph that doesn't like the muzzle brake and a scope that didn't track 100%, I was unable to verify drops beyond 700yds.

gun)

New scope planned for this rifle and more shooting to commence as soon as ski season is over

--Mark

 

[longrangehunterII]

Yes, the accuracy is great. It has taken a considerable amount of time and effort to get a load working in this rifle.

My velocity is a best guess at this point. It's right at about 2850, but due to a chronograph that doesn't like the muzzle brake and a scope that didn't track 100%, I was unable to verify drops beyond 700yds.

--Mark

Mark, you should place your chronograph 20' from the muzzle. This will eliminate the issues caused by the muzzle blast.

 

[madman]

Mark, you should place your chronograph 20' from the muzzle. This will eliminate the issues caused by the muzzle blast.

Yes, I agree, but I also plan to get the Magnetospeed which should help too

The PACT chronograph has worked well in the past, but the last outing I had issues with muzzle blast from two rifles that had never given me trouble before.

It will all get sorted out in a few months (unless the snow fails to fall )
--md

 

[barefooter56]

elmatador,
madman has it pegged. We do list the SAMMI spec. COAL in our manual Because in some cases you can get there on occasion. Most often though you have to do what madman says and throw the COAL in the book out the window OR use it as a reference to see if your seating depth sweet spot is within that spec. For you guys with Remington and Winchesters , IF you have a long action there are manufacturers of longer magazine boxes offered at WYATTS OUTDOOR CUSTOM RIFLES, BROWNELLS , MIDWAY that can be retrofitted to your rifle to give you about .110 more room to get the Hybrids and VLD bullets to run through the magazine. But again THIS DEPENDS ON THE SEATING DEPTH SWEET SPOT !
madman, the MAGNETO SPEED chronographs are great!
Hope this helps guys!
Take care,
Phil Hoham
Berger Bullet Tech