Bushing / Neck Tension issue.

[64Rambler]

I started playing with neck tension recently for my 6BRA. I started with a Wilson 266 bushing and it gives me ~0.003" interference from loaded, and the sized neck comes in at 0.2660-0.2665" with calipers, loaded round is 0.2690-0.2695" (yes, I know I should be using a micrometer and Christmas is coming, so that will solve that issue...). Then I ordered a Wilson 267 and found a good deal on a Redding TiN 265. The 267 gives me 0.2670-0.2675", but the TiN 265 is giving me 0.2630-2635". I had heard that the Redding TiN bushing sized a bit large, but I found the exact opposite. I ran gauge pins in all of them and they're right where they should be, within 0.0002". So I ordered a Wilson 265 bushing and got the exact same result; 0.2630-0.2635". And it feels like that much more interference when seating a bullet. This seems like the opposite of spring back. This is with both Alpha and Lapua brass, flame annealed. What am I seeing/missing here?

 

[NF1E]

Sounds like time for a Sinclair or other neck expanding mandrel to help out with desired neck tension my friend. Works wonders, in my opinion.
Whatta Hobby!

 

[SVT_Tactical]

I agree, a mandrel right before seating is what I use to control neck tension.

 

[JFrank]

I started playing with neck tension recently for my 6BRA. I started with a Wilson 266 bushing and it gives me ~0.003" interference from loaded, and the sized neck comes in at 0.2660-0.2665" with calipers, loaded round is 0.2690-0.2695" (yes, I know I should be using a micrometer and Christmas is coming, so that will solve that issue...). Then I ordered a Wilson 267 and found a good deal on a Redding TiN 265. The 267 gives me 0.2670-0.2675", but the TiN 265 is giving me 0.2630-2635". I had heard that the Redding TiN bushing sized a bit large, but I found the exact opposite. I ran gauge pins in all of them and they're right where they should be, within 0.0002". So I ordered a Wilson 265 bushing and got the exact same result; 0.2630-0.2635". And it feels like that much more interference when seating a bullet. This seems like the opposite of spring back. This is with both Alpha and Lapua brass, flame annealed. What am I seeing/missing here?

Wilson bushing are tapered, I like them that way because I can flip them over for a tiny extra squeeze, but regardless. I don’t get axle wrapped over trying to measure the bushing ID or mess with mandrels, just size a case and compare the neck OD to a loaded round at the CASE MOUTH and go shoot a bushing ladder at distance.
For a .269 loaded round, I would test a .266-.265-.264.

One will stand out’ then test a smaller one.

 

[243winxb]

bushings

• Unlike some other brands (like Redding, which are generally straight), Wilson bushings are designed with a slight internal taper (around 3 degrees).

Redding recommends against sizing down more than approximately 0.008" in a single step. Attempting to size down more in one pass can lead to problems such as excessive case neck runout (poor concentricity) and can cause the actual sized diameter to be smaller than the bushing's marked size due to increased brass springback and stress.

 

[64Rambler]

sizing down more than approximately 0.008" in a single step

That certainly isn't the intent, but seems to be the outcome. I'm running a 272 chamber and fired brass matches that well. The 265 bushings (straight or tapered) are giving me 2 thou more than design, pushing actual step down to 0.0085"
So I'll try 267, reanneal, then 265 and see what I get.

 

[64Rambler]

Sounds like time for a Sinclair or other neck expanding mandrel to help out with desired neck tension my friend. Works wonders, in my opinion.
Whatta Hobby!

View attachment 1713297

I have 21st Century mandrels and usually use them for virgin brass to correct any dings in the necks, but will give it a go for this.

 

[NF1E]

I think that if all necks have the same ID, you might just be a happy camper. Not so dependent on neck wall thickness. Whatta Hobby!