uh....?

1

105gr

Sergeant
Full Member
Minuteman
Jul 23, 2010
695
637
45
ohio
#1
When I started reloading I was learning on a 243. I thought since I had fireformed brass that all I had to do was size the neck so I bought a 6mm/243 neck die. Then the cases wouldn't fit in the chamber. I was told to full length resize, so I did, and it fixed the problem, which left me wondering why neck dies are even made. But that isn't the issue (for now).

I bought a Savage 112 Magnum Target in 338LM a couple years ago, wasn't happy with the performance, so I set the gun down for a couple years. I discovered that ONE of my issues was starting seating depth. Turns out the gun likes seating depths closer to SAAMI then stretched out. But thats not the issue either. (for now)

The issue right now is it's time to reload. Just last week I started reading about "bump vs FL sizing". So I took a fired case out of the tumbler, dusted it off and stuck it in the chamber. I think its 2 times fired Nosler brass. Never been annealed. (which is another issue for later). The bolt closed on the fired case like it had been resized. I could NOT do that with my 243. So a couple questions....is this even an issue? Can I just neck size? The first time I resized the brass I expected it to be way harder but it wasn't. I should have taken note of it then and asked questions then. My 243 brass takes more pressure on the press than my 338 cases. Does this mean I have a "tight chamber"? If there's no reason to overwork the brass then just neck size? Helps?
 
#2
From what you're describing on the .338 LM it sounds like you should be able to neck size only that brass. You mentioned that it is 2x fired. Did you full length size it the first time it was reloaded?

What might be going on with your .243 that has tight brass and your .338 that has loose brass is it's possible you are using a"hot" load in the .243 and a "lite" load in the .338.
 
#3
Yes. I full length resized the first time. And it seemed extremely easy to resize. Some of my primers seem to be a little cratered so I dont think its an extremely light load, however, I am experiencing slow overall MV's. Could this just be the brass? Lapua brass is crazy expensive and locally I cant even get it.
 
#4
105gr said:
When I started reloading I was learning on a 243. I thought since I had fireformed brass that all I had to do was size the neck so I bought a 6mm/243 neck die. Then the cases wouldn't fit in the chamber. I was told to full length resize, so I did, and it fixed the problem, which left me wondering why neck dies are even made. But that isn't the issue (for now).

I bought a Savage 112 Magnum Target in 338LM a couple years ago, wasn't happy with the performance, so I set the gun down for a couple years. I discovered that ONE of my issues was starting seating depth. Turns out the gun likes seating depths closer to SAAMI then stretched out. But thats not the issue either. (for now)

The issue right now is it's time to reload. Just last week I started reading about "bump vs FL sizing". So I took a fired case out of the tumbler, dusted it off and stuck it in the chamber. I think its 2 times fired Nosler brass. Never been annealed. (which is another issue for later). The bolt closed on the fired case like it had been resized. I could NOT do that with my 243. So a couple questions....is this even an issue? Can I just neck size? The first time I resized the brass I expected it to be way harder but it wasn't. I should have taken note of it then and asked questions then. My 243 brass takes more pressure on the press than my 338 cases. Does this mean I have a "tight chamber"? If there's no reason to overwork the brass then just neck size? Helps?
Click to expand...
First, when a guy gets a new chamber, and you start with new brass, after you settle on what is going to be your load, it becomes really wise to start measuring fired brass compared to new brass to determine where and how much your cases are growing. I measure the .200" line and again at the body-shoulder junction(dia), and then how much the case grew in length. This helps determine the size of your chamber, remember no matter what you will have close to .001" springback on any measurement taken.
So what type of tools do you have to do this?
Your 338 Lapua brass is some stout brass, may take 2 firings to get it to chamber dimensions, but you FL sized after one firing, how much did you bump the shoulder?
Then you ask about bump vs FL sizing, as far as I know only one company makes a shoulder bump die that does not constrict the case, and I myself do not get the validity of that die. The key to accuracy is repeatability, so what good does it do to not constrict, then have to next firing, set a baseline and go.
All FL dies constrict and shorten brass, but if you set the die right, you can actually lengthen brass by not letting the shoulder of the die come into contact with the shoulder on your brass, this can be a useful tool if brass was undersized, or the chamber is long for some reason.
What I am saying, only you can make this decision based off what readings are taken. You cannot go off the feel of 243 brass compared to the 338, it is irrelevant at this point.
As for slower velocities you are getting, maybe you need a different powder to make it work in your favor, on a big case like 338 Lapua, slower powders usually yield more speed at lower pressures.
 
#5
Benchrest shooters FL size but they usually have matched dies.

I stopped buying neck dies many years ago because often by 2-3 firings the brass has expanded too much. Instead I use custom FL dies. It's the perfect solution. Best if you own your own reamer though.

You could buy a body die for your 243 or your 338L. It bumps the shoulder back and sizes the body but leaves the neck alone.

I hate to see people force neck sized rounds into battery! It's Fuddy-ish.
 
Last edited:
#6
Milo 2.5 said:
First, when a guy gets a new chamber, and you start with new brass, after you settle on what is going to be your load, it becomes really wise to start measuring fired brass compared to new brass to determine where and how much your cases are growing. I measure the .200" line and again at the body-shoulder junction(dia), and then how much the case grew in length. This helps determine the size of your chamber, remember no matter what you will have close to .001" springback on any measurement taken.
So what type of tools do you have to do this?
Your 338 Lapua brass is some stout brass, may take 2 firings to get it to chamber dimensions, but you FL sized after one firing, how much did you bump the shoulder?
Then you ask about bump vs FL sizing, as far as I know only one company makes a shoulder bump die that does not constrict the case, and I myself do not get the validity of that die. The key to accuracy is repeatability, so what good does it do to not constrict, then have to next firing, set a baseline and go.
All FL dies constrict and shorten brass, but if you set the die right, you can actually lengthen brass by not letting the shoulder of the die come into contact with the shoulder on your brass, this can be a useful tool if brass was undersized, or the chamber is long for some reason.
What I am saying, only you can make this decision based off what readings are taken. You cannot go off the feel of 243 brass compared to the 338, it is irrelevant at this point.
As for slower velocities you are getting, maybe you need a different powder to make it work in your favor, on a big case like 338 Lapua, slower powders usually yield more speed at lower pressures.
Click to expand...
I did not measure fired brass against new brass. At the time I didn't know that was a thing I was supposed to do. Right now the only tools I have to do this would be a set of calipers. After I FL sized the brass i do not know how much the shoulder was bumped. I set the FL die up in the press the way it says in the die manual and sized everything. The shell holder is supposed to bump the bottom of the die right? As for saying anything about the 243 brass I was just stating an observation. If my 243 brass was not FL sized I could not put a fired case back in the chamber and close the bolt, which may mean my 243 brass needs annealed really badly. As for 338 powders, only recently have I been able to obtain anything but H1000. I have some RL33 I want to try with the 300's and have a decent load with 285's with the H1000
 
#7
I neck size only new brass; that's the only time I use that particular die. Otherwise I just bump the shoulder using FL die.
 
#8
steve123 said:
Benchrest shooters FL size but they usually have matched dies.

I stopped buying neck dies many years ago because often by 2-3 firings the brass has expanded too much. Instead I use custom FL dies. It's the perfect solution. Best if you own your own reamer though.

You could buy a body die for your 243 or your 338L. It bumps the shoulder back and sizes the body but leaves the neck alone.

I hate to see people force neck sized round into battery! It's Fuddy-ish.
Click to expand...
So can I just neck size untill the brass stretches out till it doesnt fit the chamber then FL size? Say neck size 2 or 3 firings then FL size repeat?
 
#11
105gr said:
I did not measure fired brass against new brass. At the time I didn't know that was a thing I was supposed to do. Right now the only tools I have to do this would be a set of calipers. After I FL sized the brass i do not know how much the shoulder was bumped. I set the FL die up in the press the way it says in the die manual and sized everything. The shell holder is supposed to bump the bottom of the die right? As for saying anything about the 243 brass I was just stating an observation. If my 243 brass was not FL sized I could not put a fired case back in the chamber and close the bolt, which may mean my 243 brass needs annealed really badly. As for 338 powders, only recently have I been able to obtain anything but H1000. I have some RL33 I want to try with the 300's and have a decent load with 285's with the H1000
Click to expand...
For as much as that brass cost, you need to get a bump gauge, you do not want a case coming apart in the chamber from case head separation, i'll grab a link here in a bit.
 
#13
Just Full Length size. The rule with Neck sizing is after a certain amount of firings you'll still get a click on close or a sticky bolt and need to hit the case with a body die or FL size it. It's more consistent to just FL size every time. Ideally, you want to work the brass as little as possible, so once you have some formed cases, find the amount of sizing that creates smooth bolt operation and you're good.
 
  • Like
Reactions: strat81
#15
105gr said:
So can I just neck size untill the brass stretches out till it doesnt fit the chamber then FL size? Say neck size 2 or 3 firings then FL size repeat?
Click to expand...

FL size every time, don't jack around with the neck sizing.

An excellent tool is the Innovative Technologies shoulder bump measuring gauge. It'll measure any bottle necked case without having to buy bushings every time you get another cartridge.
 
  • Like
Reactions: strat81
#17
105gr said:
Do I need bushings for that? Or just set the die higher in the press?
Click to expand...

Bushings on dies control how much the neck is sized, and therefore set the neck tension.

By screwing the full length die further into the press, you cause it to 'bump' the shoulder further down towards the head of the case. Likewise, unscrewing it a bit will mean the shoulder is 'bumped' less far.

A comparator attaches to your calipers and measures a datum line on the shoulder to the base of the case. This can be used to determine 'bump.' For example, my 6.5 with a 400 comparator reads 1.5380 when fired. After resizing, it reads 1.5365. This means I have moved the shoulder 0.0015 closer to the case head, or 'bumped' it one and a half thou. Generally, people recommend bumping 2 thou for bolt actions, and 3 to 4 for semi autos. This will minimize how much your brass is worked during each resizing and firing, to improve case life.
 
You must log in or register to reply here.

Similar threads

J
Rough Rust-like finish inside alpha brass necks
Replies
27
Views
657
Dolomite
D
Basic user
Neck Tension Inconsistencies on Lapua 6.5CM Brass
Replies
41
Views
822
Sooner Sniper
Sooner Sniper
RTTY
Chambering issue after expander mandrell.
Replies
48
Views
981
Ex E6
Ex E6
R
Dimpled case neck after sizing?
Replies
4
Views
152
rustyinbend
rustyinbend
J
Fouling past the case neck
Replies
33
Views
996
JRBullock1987
J
Top Bottom
Back
Home
Forums
Merch
Alerts