LBT, 30 cal., 180 gr.

Ole_270

Well-Known Member
Thanks Ben, check going out today.
Man, this makes the third mold I've bought to play with for this old 308. Starting to seem like I'd of been money ahead to use the HVA action as a donor for a custom 7x57 like originally planned. Oh well, us old retired folks got to have something to do besides sit in the recliner.
 

Todd M

Craftsman of metals...always learning.
Ben is this the quickest turn around you have had buying then selling a mold? Been fun watching!
 

Ben

Moderator
Staff member
Todd M

Ole 270 has purchased the mould.

I had it less than 24 hours.
Yes, it set a record...............

Ben
 
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Ole_270

Well-Known Member
Got the LBT mold today, thanks Ben for the prompt shipping. Fired up the pot and started trying to fit handles. My Lyman 2 cavity handles weren't long enough so I switched to the Lee 6 cavity hangles. These were very tight in the mold slots. I measured the slots at .310, my Lee, Noe and Accurate multi cavity molds all went .320-.322. The Lee handles measured .308 but wouldn't go in the slots, so they are evidently warped somewhat. I went to work with files and stones till the handles would fit, still too tight, but enough to get a couple dozen castings to work with.
I had some trouble making sure the blocks were completely closed due to the fit problem with the handles, but ended up with a couple dozen good castings. I made up a dummy round and what do ya know, I've finally got one that will completely fill the throat. Too much so in fact. I must of gotten carried away with adding tin to the pot, the nose section measured .312 I went ahead and PC'd/water dropped them and fit gas checks while sizing to .3115. The thermometer on the tray with the bullets was at 415 when I stepped back into the shop to check on them. Pretty sure they were at 400+ for at least 25 minutes.
I made up another dummy after they were sized and had to seat it fairy short to get the bolt to close. Still closing fairly hard with the bullet seated slightly past the crimping groove. I took a picture that shows the lands engraving the full length of the nose and hopefully you can see that for roughly .25" it was scuffed by the groove as well. Not sure if I'll have to setup to nose size these or not.
I'll set them aside for awhile to fully harden and do some shooting to see how they work.
iilH4Mu.jpg
 

Ole_270

Well-Known Member
That doesn't show up very well on my monitor. I used a gray PC and colored it up with a black sharpie. You can see that the land engraves to about .06-.07 from the case mouth. You can't see it but, it's making good contact with the groove diameter for .100 or so from that heavier mark and real light up to .25 from there.
 

fiver

Well-Known Member
now you finally got something to work with.
I like to make very small runs of bullets when I get started so I can catch things like you did.
now you have an idea about alloy and stuff.
 

Ole_270

Well-Known Member
Small run is correct, after some long runs with 5 and 6 cavity blocks this seemed to take forever to get anywhere.
 

Ben

Moderator
Staff member
Ole 270 :

Glad to see you are having quick success with the LBT Mould. :):):)

Ben
 

fiver

Well-Known Member
remember step,,,step,,,step.
you have a picture of your throat and your getting the bullet to mimic it from the mold,,, step.
 

Ole_270

Well-Known Member
Question, just how hard should contact be with the groove? Obviously, if it's very much it's going to be hard to close the bolt. Maybe size to a half thousandth under the groove contact diameter? The sizer bushing I'm using now is marked .311 but I'm getting .3115. Alloy hardness will vary that size I'm sure.
 

fiver

Well-Known Member
if it's taking the rifling and it's taking it evenly all the way around your good.

I'm setting up my XCB ammo like I did first go round last spring.
I'm running about .001 neck tension, seating about .0020 too long, and letting the bolt do the final seating.
I get away with it because I have about .001 worth of room around the case in the neck, and just barely enough room around the bullet in the ball seat area for it to chamber without touching.
I don't think I could measure how much there is with the tools I have here.

a little side thought.
I think your gonna find some of that lost velocity with the way you have it fit now.