WW vs WW + 2% Tin

5shot
Posts: 7
Joined: Thu Oct 18, 2012 4:23 pm

WW vs WW + 2% Tin

Postby 5shot » Thu Oct 18, 2012 4:41 pm

How will the final diameter change between the two? I am looking to design a bullet for the 35 Whelen. I usually add Tin to my WW, and I was curious.

User avatar
mtngun
Site Admin
Posts: 1636
Joined: Fri Feb 01, 2008 5:45 pm
Location: Where the Salmon joins the Snake

Re: WW vs WW + 2% Tin

Postby mtngun » Fri Oct 19, 2012 8:41 am

There is no predictable diameter change for a given alloy. Depends on the bullet design, the block, the casting technique, etc.. WW&tin may cast smaller in one mold and larger in another mold. Or it may cast larger at one temperature and smaller at another temperature. Or it may cast larger on the front band and smaller on the bottom band. Many variables.

5shot
Posts: 7
Joined: Thu Oct 18, 2012 4:23 pm

Re: WW vs WW + 2% Tin

Postby 5shot » Fri Oct 19, 2012 1:31 pm

Thanks. I will order my mold for WW + 2% Tin, as that is what I typically use.

5shot
Posts: 7
Joined: Thu Oct 18, 2012 4:23 pm

Re: WW vs WW + 2% Tin

Postby 5shot » Thu Oct 25, 2012 4:54 am

I have a follow up to this:

Which mold has a larger machined diameter - the WW or the WW + 2%?

The reason I ask, is if the the WW + 2% is smaller, and I lose some tin from the mix, I might end up with bullets too small for the bore (or I need to order the mold larger).

Thanks.

User avatar
mtngun
Site Admin
Posts: 1636
Joined: Fri Feb 01, 2008 5:45 pm
Location: Where the Salmon joins the Snake

Re: WW vs WW + 2% Tin

Postby mtngun » Thu Oct 25, 2012 9:55 am

All my molds are cut by trial and error. I have no formula for predicting the machined diameter.

As long as your bullet drops out 0.002" oversize, you have wiggle room to allow for variations in alloy and casting technique. Unless you are talking about a bore riding nose, in which case, you just stumbled onto one of many issues with the bore riding design. ;)

5shot
Posts: 7
Joined: Thu Oct 18, 2012 4:23 pm

Re: WW vs WW + 2% Tin

Postby 5shot » Fri Oct 26, 2012 2:54 pm

mtngun wrote:All my molds are cut by trial and error. I have no formula for predicting the machined diameter.


I guess what I was trying to get at is: If I ordered 2 identical molds, but specified WW on one and WW + 2% on the other, which would have the larger machined diameter?

mtngun wrote: Unless you are talking about a bore riding nose, in which case, you just stumbled onto one of many issues with the bore riding design. ;)


Well, that is the other half of it, as it will have a bore ride nose on it. My bore mics at 0.352" - I was planning on order the bore ride section at 0.351" .

User avatar
mtngun
Site Admin
Posts: 1636
Joined: Fri Feb 01, 2008 5:45 pm
Location: Where the Salmon joins the Snake

Re: WW vs WW + 2% Tin

Postby mtngun » Sat Oct 27, 2012 11:52 am

5shot wrote: I guess what I was trying to get at is: If I ordered 2 identical molds, but specified WW on one and WW + 2% on the other, which would have the larger machined diameter?


I do not know. Different molds and different bullet designs cast differently. Sometimes the tin bullet will cast larger (typical on a small bore bullet) other times the tin bullet will cast smaller (it sometimes happens on a big bore). Or the tin bullet might cast smaller near the bottom of the bullet and cast larger near the top of the bullet. Casting is not a precision process. That's what sizing dies are for, IMHO.

5shot wrote: it will have a bore ride nose on it. My bore mics at 0.352" - I was planning on order the bore ride section at 0.351" .


That sounds reasonable, though most people prefer the nose to engrave slightly if it is a bolt action.

Bench rest shooters bump & size their noses. That is the only sure way to ensure a particular diameter.

Bear in mind that it is common for the nose diameter to be unintentionally "bumped up" in the lubrisizer, especially on smaller diameter bullets, though I do not anticipate that happening with 35 caliber. Or, the nose diameter may vary from one pour to the next due to lead splatter on the mold faces, etc.. Casting is not a precision process.


Return to “design & sizing”

Who is online

Users browsing this forum: No registered users and 3 guests

cron