Redding Type S Bushings?

[CSI]

I have a question about determining the proper size for the Redding bushing.
I have searched and read all the posts concerning this topic however my circumstance doesn’t seem to be addressed in them.

I have new Lapua .308 brass and 175g Sierra Match King bullets for components.

I am planning to reload these on a yet to be purchased Forster Co-Ax press. I want to purchase the Redding dies now and need to determine the bushing size without being able to measure a “loaded” round using my components.

Question:
Can I simply measure the wall thickness of my cases at the neck and then double that and add it to the dimension of the bullet to determine what the OD at the neck will be?

Will the neck wall thickness change a measurable degree after the case necks have been fire formed and resized the first time?

Thanks,

 

[Suasponte]

Re: Redding Type S Bushings?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MikeP</div><div class="ubbcode-body">Can I simply measure the wall thickness of my cases at the neck and then double that and add it to the dimension of the bullet to determine what the OD at the neck will be?

Will the neck wall thickness change a measurable degree after the case necks have been fire formed and resized the first time?

</div></div>

1) Yes that is the way to do it! Minus the neck tension that you desire .001 -.003 usually.

2) No, your neck wall thickness should not increase by any measurable amount.

Terry

 

[Victor N TN]

Re: Redding Type S Bushings?

+ 1...

Terry covered it pretty well.

 

[HomeSlice]

Re: Redding Type S Bushings?

Regarding neck tension: is the range of .001 - .003 the same for naked vs. moly coated?

How do you decide on which side of this range to go?

Thanks,
-Slice

 

[Victor N TN]

Re: Redding Type S Bushings?

I get a -.002" bushing from the start.

If you can push the bullet down with your thumb, (not holding a metal object under your thumb either) after seating it, it's too loose.

Going to -.003" is a thing I only use depending on the powder. Some loads prefer a tight neck tension to get the pressure curve started hot.

 

[DENAUS4]

Re: Redding Type S Bushings?

Hi Mike provided that you can measure the neck thickness accurately that will work fine. It would be probably more accurate to measure a loaded round as it is just an easier measurement to take accurately. They might be some thinning in the brass once loaded but it would be a very very small amount.

Cheers Lachlan

 

[CSI]

Re: Redding Type S Bushings?

I was worried about the accuracy in measuring in this manner and any compounding error that may be occurring.
A chicken before the egg problem. I need the dies to load the round but can’t order the dies without a loaded round.
I think I will look for someone to seat the bullet in an empty case for me to obtain the most accurate measurement.

Thanks to all who responded

 

[4Rail_Gunner]

Re: Redding Type S Bushings?

You didn't say what gun you were running it through.
So i'll add alittle bit.
If your using a gas gun (AR-10) use a .003 neck tension.
And just for added security i would follow up with a Lee factory crimp die.

Bolt guns, the guys said it well.

Good Luck =)

 

[Suasponte]

Re: Redding Type S Bushings?

The only real way to get the benefit of neck bushings fully is to neck turn. This ensures that you have a consistent neck wall thickness all round. I typically take my brass and measure the necks, then I set my neck turner to the depth of cut I want with a automotive feeler gage (typically .001 smaller than my smallest measured dim). Then I know exactly what my neck thickness is and that it's consistent around the whole neck. If you exaggerate looking at a case neck most of them would look like two circles that do not share a common center point. Neck turning evens that out, and ensure a consistent tension 360 degrees around your neck.

Some guys have their chambers set for a certain neck dimension so they have to neck turn.

Make sure that you measure at more that one point on your necks! If you don't you are not going to get a accurate reading. I have yet to see any brass that has not been neck turned have a consistent wall thickness at 4 to 6 point around the neck.

Take a loaded round and hold your calipers on the neck and spin it while applying pressure! You will see it move anywhere from .001 to .004 sometimes.

I guess what I am trying to say is unless you turn all your necks to the same wall thickness your neck tension will vary from round to round depending on the amount of wall thickness that you have on your brass!

I'll stop there!

Terry