338 LAI .015 ES in shoulder bump, Lapua brass, why?

[Sgt. Brumbaugh]

I measure shoulder bump on all my match brass and am used to seeing .0005 ES in the shoulder bump with Micron dies in my 300 NMI using Lapua brass

I am getting my feet wet on a 338 LAI using WTC dies and am getting .015 ES in the shoulder bump. I use the exact same procedure (hold brass at top of the stroke for 3 seconds) same lube, etc for both cartridges. When I ran a 33 XC I was pretty used to seeing .001 or less SB ES.

I do not anneal (at least not this or any of the above brass) and all the 338 brass has the same number of firings.

Any thoughts? I can't think of any reason why this brass should have such a large ES in the SB.

 

[Alan Warner]

Call me next week and we will figure it out.

 

[Sgt. Brumbaugh]

Alan,

First, like an idiot. I forgot to add in a zero. It is .0015, not .015. I would just edit the original post- but don't want people to think I am pointing the finger at your dies. I think there is something else going on.

 

[WAMBO]

Personally I don't see anything wrong with .0015" shoulder bump.

 

[Sgt. Brumbaugh]

It is not the .0015 SB, it is the ES of .0015 that is the issue.

 

[DaveTooley]

What does the bolt handle tell you? Any negative feedback?

 

[Sgt. Brumbaugh]

What does the bolt handle tell you? Any negative feedback?

What exactly do you mean Dave? If you are referring to how the brass fits the chamber- yes, with no bolt resistance (with firing pin and ejector removed) the brass fits perfectly as it closes with no tension, bolt flops closed. If you are referring to accuracy- I am just getting my feet wet with this new rifle.

 

[DaveTooley]

I did a 338 Lapua Imp a long time ago. I went 30 degree shoulder angle. That's a large diameter case with a wide shoulder area. You're basically compressing the side walls, not massaging the entire case. If I was getting .0015" variation in shoulder bump with no operating issues I would be happy.

 

[NZ_Fclass]

Please let us know how this affected accuracy? I have doubts that you can tell the difference on target.

 

[Sgt. Brumbaugh]

I was able to get a little more cam over in my die, that and running the brass through the die twice I was able to get the ES down to .001 for 99/100 pieces of brass. Total bump of .002.

This is a competition ELR rifle, so I am trying to leave no stone unturned.

 

[Evlshnngns]

I got an annealer because I got an ackley and didn't want to loose the brass to a cracked neck or shoulder. It was crazy how much easier it was to size the brass after. If it hasn't been annealed since being fire formed, I would do it.

 

[SKWERLZ]

.0015 variance on a big case without annealing is pretty good.

 

[ronemus]

How many firings? The brass will work harden, and that usually isn't consistent (especially if different loads were used). Annealing will improve uniformity, and that should reduce your ES.

My .338 LM brass sizes very uniformly (ES <0.001") in part because I anneal after every firing.

When brass costs $3 a case, I make every effort to extend its life, which is my primary reason for annealing.

 

[Alex Wheeler]

When it comes to the 338 limp the press becomes a little more important.

 

[Sgt. Brumbaugh]

When it comes to the 338 limp the press becomes a little more important.

I use the Redding Big Boss 2.

 

[jackieschmidt]

Call me next week and we will figure it out.

Alan, I am just about finished with my 338 Lapua Improved, 40 degree shoulder. I just haven’t fired the Rifle as of yet.

I have new Lapua cases coming to fireform. Do I send you two fired cases?

Also, is a Rock Chucker stiff enough for this case? I know your dies are on 1 1/4 12tpi, I have several Rock Chuckers from which I can remove the insert.

 

[Coyotefurharvester]

What tools are you measuring with?

 

[Alan Warner]

Alan, I am just about finished with my 338 Lapua Improved, 40 degree shoulder. I just haven’t fired the Rifle as of yet.

I have new Lapua cases coming to fireform. Do I send you two fired cases?

Also, is a Rock Chucker stiff enough for this case? I know your dies are on 1 1/4 12tpi, I have several Rock Chuckers from which I can remove the insert.

I like to see 3 or 4. A reamer print for reference is also a good thing.
The rock chucker is fine.
Im in the midst of drawing a group of die inserts, so your timing is spot on.
If you have specific numbers you'd like, let me know. I shoot for 2 or 3 at the top and 1 to 2 at the bottom. Necks on that one @ 3 or what ever you want.

 

[jackieschmidt]

I like to see 3 or 4. A reamer print for reference is also a good thing.
The rock chucker is fine.
Im in the midst of drawing a group of die inserts, so your timing is spot on.
If you have specific numbers you'd like, let me know. I shoot for 2 or 3 at the top and 1 to 2 at the bottom. Necks on that one @ 3 or what ever you want.

PM sent

 

[Alan Warner]

PM sent

I just remembered, I have a couple of half shot out 338 barrels that could be used as fire form donors if you like. Just say the word.
Alan