1X fired Lapua 308 Win Brass Reloading Question

[Sgtsideways]

Hopefully I'll word this correctly. I just came across the Berger 200.2x 30cal bullets and went to seat them in 1x fired Lupua 308 Win brass. Seating pressures were unusually high (65-100psi) compared to the 185g Juggs (35-45psi). Brass prep was the same as I have always done, so I thought what the hell?

Fired rounds of the brass were about 0.340" o.d., and I am aiming for 0.337" o.d. after fl sizing with s type die. This gives me a neck tension of about 0.002. What I found, after experimenting, was going with a 0.338 bushing followed by a 0.337 bushing resulted in seating pressures of 35-40psi. A big difference with this extra step.

So my question is this: If I used a fl sizing die with 0.338" bushing followed by a neck sizing only die with a 0.337" bushing, am I creating more problems in trying to save time? This as opposed to just changing out bushings in the original fl type s sizing die?

 

[918v]

Hopefully I'll word this correctly. I just came across the Berger 200.2x 30cal bullets and went to seat them in 1x fired Lupua 308 Win brass. Seating pressures were unusually high (65-100psi) compared to the 185g Juggs (35-45psi). Brass prep was the same as I have always done, so I thought what the hell?

Fired rounds of the brass were about 0.340" o.d., and I am aiming for 0.337" o.d. after fl sizing with s type die. This gives me a neck tension of about 0.002. What I found, after experimenting, was going with a 0.338 bushing followed by a 0.337 bushing resulted in seating pressures of 35-40psi. A big difference with this extra step.

So my question is this: If I used a fl sizing die with 0.338" bushing followed by a neck sizing only die with a 0.337" bushing, am I creating more problems in trying to save time? This as opposed to just changing out bushings in the original fl type s sizing die?

I think you have your measurements wrong.

I know that a loaded Lapua 308 neck measures .337”. So if you want .002” neck tension you’ll need to get it down to .335”.

 

[Dolomite]

Sounds like the OP talking about neck chamber clearance between fired brass .340 and loaded round of .338. Assuming no neck turn brass a .335 bushing with get you to about .002 neck tension or interference fit. A .337 bushing will be the same size as your loaded round which means almost no neck tension. .335 or .336 with get you to the .002 neck tension.

 

[rustyinbend]

Lots there ... I'll contribute by just telling you what works for my Berger 200.20x bullets in my 300-WM ... I use a .333 SAC bushing in my Reading Type-S FL die, and then a .308 mandrel. The result is great initial seating force in the 20's, and terminal seating force around 35-ish ... measure on my AMP Press. Rifle shoots out to a mile with good accuracy using that sizing technique. Consider a mandrel set from 21st Century to be able to really fine-tune your necks end-state.

 

[Sgtsideways]

I think you have your measurements wrong.

I know that a loaded Lapua 308 neck measures .337”. So if you want .002” neck tension you’ll need to get it down to .335”.

Not really. Berger manufactured ammo, 308 Win 185 OTM measures .339"

 

[Sgtsideways]

Lots there ... I'll contribute by just telling you what works for my Berger 200.20x bullets in my 300-WM ... I use a .333 SAC bushing in my Reading Type-S FL die, and then a .308 mandrel. The result is great initial seating force in the 20's, and terminal seating force around 35-ish ... measure on my AMP Press. Rifle shoots out to a mile with good accuracy using that sizing technique. Consider a mandrel set from 21st Century to be able to really fine-tune your necks end-state.

Hey Rusty,
Got the same equipment as you, except for the amp press. I will admit that my eyes tire, looking at the gauge on the arbor press.

I'm trying to get away from moly lube on the inner neck, so I've now gone to the two steps of sizing the neck with the redding S. This has really helped reduce the seating psi's and, like you,
I'm getting most rounds coming in at the 35-45 psi range. I think the whole problem was trying to size down too much in one operation.

As I explained to Dolomite, below, I'm getting .001 neck tension with .338 followed by .337 bushing. If I go to the .336 bushing, my neck tension is at .002 and loaded rounds are at .339". Just like the loaded Berger Manufactured 308 Win 185g OTM. Hopefully, this will also result in lower es and sd on my rounds, so lots to experiment with..........keeps you young!

Sounds like the OP talking about neck chamber clearance between fired brass .340 and loaded round of .338. Assuming no neck turn brass a .335 bushing with get you to about .002 neck tension or interference fit. A .337 bushing will be the same size as your loaded round which means almost no neck tension. .335 or .336 with get you to the .002 neck tension.

You are correct in your interpretation. Also, I was using .338 followed by .337 bushings resulting in a neck tension of around .001-.0015", not a great idea for semi-auto, but has worked well in my bolt actions.
My only concern at this point is whether I'm working the brass too much by sizing 2x., and the extra time involved. Thanks for you input.

 

[Dolomite]

Hey Rusty,
Got the same equipment as you, except for the amp press. I will admit that my eyes tire, looking at the gauge on the arbor press.

I'm trying to get away from moly lube on the inner neck, so I've now gone to the two steps of sizing the neck with the redding S. This has really helped reduce the seating psi's and, like you,
I'm getting most rounds coming in at the 35-45 psi range. I think the whole problem was trying to size down too much in one operation.

As I explained to Dolomite, below, I'm getting .001 neck tension with .338 followed by .337 bushing. If I go to the .336 bushing, my neck tension is at .002 and loaded rounds are at .339". Just like the loaded Berger Manufactured 308 Win 185g OTM. Hopefully, this will also result in lower es and sd on my rounds, so lots to experiment with..........keeps you young!

You are correct in your interpretation. Also, I was using .338 followed by .337 bushings resulting in a neck tension of around .001-.0015", not a great idea for semi-auto, but has worked well in my bolt actions.
My only concern at this point is whether I'm working the brass too much by sizing 2x., and the extra time involved. Thanks for you input.

Sizing it 2x might put stress on the brass but you would have to test over a longer period of time. You can try annealing it between the sizings if that is an option but totally up to you.

 

[rustyinbend]

Hey Rusty,
Got the same equipment as you, except for the amp press. I will admit that my eyes tire, looking at the gauge on the arbor press.

I'm trying to get away from moly lube on the inner neck, so I've now gone to the two steps of sizing the neck with the redding S. This has really helped reduce the seating psi's and, like you,
I'm getting most rounds coming in at the 35-45 psi range. I think the whole problem was trying to size down too much in one operation.

As I explained to Dolomite, below, I'm getting .001 neck tension with .338 followed by .337 bushing. If I go to the .336 bushing, my neck tension is at .002 and loaded rounds are at .339". Just like the loaded Berger Manufactured 308 Win 185g OTM. Hopefully, this will also result in lower es and sd on my rounds, so lots to experiment with..........keeps you young!

You are correct in your interpretation. Also, I was using .338 followed by .337 bushings resulting in a neck tension of around .001-.0015", not a great idea for semi-auto, but has worked well in my bolt actions.
My only concern at this point is whether I'm working the brass too much by sizing 2x., and the extra time involved. Thanks for you input.

I size down with my SAC bushings and then expand with a mandrel. I suppose this can be considered working the brass twice, but I anneal after every firing and have seen no degradation in my brass over 5+ firings ... so I like my process and will stick with it. I get consistent velocity, single digit SD's, tight groups, accuracy at distance, and excellent pre-and-post-seating concentricity. What's not to like?

 

[JS/]

I always take the extra time and resize in two steps with the final bushing a .335 inch for .308 Win. cartridges. Then I seat with a Redding Competition seating die with the sliding sleeve. The resulting ammunition shoots well. This is with Lapua brass.