.338 L/M brass burning through

[338sniper]

I'm reloading .338 L/M with 83 grains of IMR4350 and after 4-5 reloadings I'm getting an outer "burn through" band around the base of the brass. Is this normal after so few reloadings ? would changing to a different powder help ? Thanks for any help ypu can offer

 

[sinister]

Re: .338 L/M brass burning through

You are looking at an incipient case head separation -- usually caused by setting the shoulder too far back during resizing, causing your case walls to thin and eventually separate.

You should use calipers and a Stoney Point (or equivalent) case headspace gage to set your sizing die.

 

[ChrisGarrett]

Re: .338 L/M brass burning through

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sinister</div><div class="ubbcode-body">You are looking at an incipient case head separation -- usually caused by setting the shoulder too far back during resizing, causing your case walls to thin and eventually separate.

You should use calipers and a Stoney Point (or equivalent) case headspace gage to set your sizing die.

</div></div>

Exactly.

I'm on 12 cycles for most of my Lapua/Norma stuff and they're still working well.

Invest the $45 in the Hornady/SP headspace gages and never have that happen to you again.

Might as well spend another $55 and get their bullet comparators and modified case gages to help you find the lands, while you're at it.

Chris

 

[338sniper]

Re: .338 L/M brass burning through

Once I get the gage , what am i setting on my die ? the distance between the shell holder and the base of the die ?

 

[aloreman]

Re: .338 L/M brass burning through

measure a case you fired and adjust the die down till you get .001 to .002 less than the shell you measured

 

[427Cobra]

Re: .338 L/M brass burning through

Decap all your fired brass, use the HSG(head space gauge) and measure them, they might all be the same length, but I usually find a couple that are a couple thou longer than the rest, use those to setup the FL die to bump the shoulder back.

 

[338sniper]

Re: .338 L/M brass burning through

I know this is a stupid question without having the gage yet , and I appologize , but ,,,,, (A) is the ultimate goal to have the case flush against the bottom of the gage , thus creating the proper headspace ? And (B) is the problem im having because the brass is sitting top deep in the gage or sticking out to far from the gage. Sorry guys but this is all new to me and I want to do it right

 

[BirdEyes]

Re: .338 L/M brass burning through

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: serenesniper</div><div class="ubbcode-body">I know this is a stupid question without having the gage yet , and I appologize , but ,,,,, (A) is the ultimate goal to have the case flush against the bottom of the gage , thus creating the proper headspace ? And (B) is the problem im having because the brass is sitting top deep in the gage or sticking out to far from the gage. Sorry guys but this is all new to me and I want to do it right </div></div>

It looks like the key point that you may be missing is that the gauge insert stops on/near the datum point on the shoulder. The brass does not fit inside of the proper gauge. it only goes as far as the datum point. The length you are measuring and trying to control is the length between the datum point and the case head. The idea is to measure your fired case and get this measurement and then set your die to make resized cases measure 1/2 thousands less than what you measured with this same tool.

 

[sinister]

Re: .338 L/M brass burning through

A gage will show minimum (flush with the bottom dimension) to maximum allowable length (usually SAAMI dimensions). Your chamber may be cut somewhere in between.

Resizing the shoulder anything more than around 2 thousandths allows your brass to "Stretch" every time it's fired, lengthening and thinning your case walls. If it's always set to maximum set-back your cases will thin faster (as yours are).

In other words, if your chamber is cut long and you always resize to minimum head-to-shoulder datum dimension length your cases are going to stretch farther and thin with every shot.

 

[elephantrider]

Re: .338 L/M brass burning through

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: serenesniper</div><div class="ubbcode-body">I know this is a stupid question without having the gage yet , and I appologize , but ,,,,, (A) is the ultimate goal to have the case flush against the bottom of the gage , thus creating the proper headspace ? And (B) is the problem im having because the brass is sitting top deep in the gage or sticking out to far from the gage. Sorry guys but this is all new to me and I want to do it right </div></div>

I'll attempt to clear this up for you.
As someone already mentioned, what you are seeing on your cases is evidence of an imminent case head separation. A potnetially dangerous situation, so do not use those cases any more. Here is a good article on it, so that you can understand it a little better:

http://riflemansjournal.blogspot.com/2010/05/reloading-case-head-separations.html

The issue you are having isn't really related to any guage, but more likely due to how you have you reszing die set up. You probably have you die turned to far down into the press and are over resizing the brass and creating an excessive headspace situation (look up "headspace" if you are unfamiliar). The guage will simly let you measure your fired cases so that you have a reference point from which to set up your resizing die properly. Proper sizing should only bump the shoulder back by 0.001-0.002" as others have noted already.

 

[338sniper]

Re: .338 L/M brass burning through

Ok , hold on , I think I got it, correct me if im wrong...
1) fired case...
2) insert in gage (hopefully with it sticking out )
3) measure the distance
4) back out my FL resizing die a few turns from where it is
5) resize brass
6) keep resizing till im .001/.002 less the my original measuement
7) ok , fingers crossed ,,, ladies and gentlemen do we have a winner ???????

 

[427Cobra]

Re: .338 L/M brass burning through

You need to decap the brass first, that way there is no chance of the HSG reading being skwed by primer flow

 

[HotrRod308]

Re: .338 L/M brass burning through

You might want to look at Retumbo, RL 25, or H4831SC..... I think IMR 4350 may be a little to fast burning for the .338

I have had the best luck with the Retumbo in my .338 LM.

 

[jfseaman]

Re: .338 L/M brass burning through

I don't load for 338LM as I am trying to decide whether to go with 338LM or 338RUM to build out my Wby Mark V. Maybe 300RUM, hmmm 208 A-Max at 3250fps

but I digress...

IMHO

Discard that lot of cases, they are now dangerous.

If you are FL sizing each firing, stop and get a neck sizing die. I am now migrating to Lee collet as it works the brass less.

If you are neck sizing, you might have your die to low. Use a sharpie mark the neck and only size down as far as you need to. IMHO a couple thou of unsized neck to ensure you don't crush the case or bump it with a neck sizing die (ask me how I know) creating excessive head space.

As has been mentioned above, when you do FL size, bump the minimum amount. When I FL size, I anneal first so that I'm working the shoulder brass and not pushing the work hardening all the way down to the webbing.

and last

I really believe that all the 4350's are too fast for a 338 LM unless you are throwing Barnes 160 or 185 only. H4381, rl 22 or 25, IMR7828, H1000, or anything slower than IMR7828.

What I do: I lave limited experience but I prefer to find the powder that covers the largest range of projectile weights for my chambering that also pushes the projectiles pretty fast with the lowest pressure.

Using your caliber, (I favor Olin products) I would choose IMR7828 because it is listed for everything from Barnes 165gns to Sierra 300gns MKs, doesn't top the speed charts for the heavy weights but most important does not top the pressures. H-1000 or H-4381 would be a close second.

Be safe and have fun

 

[alaska bush man]

Re: .338 L/M brass burning through

whay are you using IMR 4350 in a 338 Lapua?

 

[338sniper]

Re: .338 L/M brass burning through

I also use it in my .338 win mag. What do you recommend and why if you dont mind me asking. Also guys please feel free to post what you guys use and your results.

 

[jfseaman]

Re: .338 L/M brass burning through

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: serenesniper</div><div class="ubbcode-body">I also use it in my .338 win mag. What do you recommend and why if you dont mind me asking. Also guys please feel free to post what you guys use and your results. </div></div>If you want to keep with the same powder for both, IMR-7828 but not SSC. If you are willing to use different powder for each caliber, Retumbo!

 

[338sniper]

Re: .338 L/M brass burning through

Great information guys ,, Thanks

 

[Sniper Uncle]

Re: .338 L/M brass burning through

Thanks for the info, guys. I guess I need to get a gauge for my casings. I sure don't want to have a separation.

 

[chariotdriver]

Re: .338 L/M brass burning through

Get a set of Redding competition shell holders......or start neck sizing.

Slower powder as well. I use 91gr Retumbo for around 2700' and 102gr H50BMG for 2650' but it's fairly compressed. The latter works better with the titan-qd and I don't know why.

When a case separates it will get your attention.