Cast Boolit Diameter Accuracy

[TXCOONDOG]

I've been casting for 6 years or so for pistols using WW + 2% Tin at 750 degrees. My cast booits always came out over the size I needed.

I decided to casting for a Marlin 336 XLR in 30-30 (12 twist) and the barrel slugs at .3085". The plan was to cast, powder coat and size .311". I bought a Lee 309-170 & 309-150 and cast with the 309-170 mold today using 50/50 WW & Pure PB + 2% tin.

The boolits dropped at .309" exactly. If I powder coat to get the additional .002" needed, will I still get the same accuracy as if the boolits cast at .311", powder coat (adds .001-.002") and size to .311"?

Just thinking and wondering (if I need to lap my mold).

[jaysouth]

Try .310 and .311. Your rifle will tell which is best for your rifle. Have you slugged the chamber? Fit the bullet to your chamber.

[BLAHUT]

Try pure lead at about 1200fps. Gun will tell you if it likes it. Mine is very accurate with this.

[TXCOONDOG]

Try .310 and .311. Your rifle will tell which is best for your rifle. Have you slugged the chamber? Fit the bullet to your chamber.

How do you slug a chamber? Never heard of slugging a chamber but have heard of casting a chamber.

[MrWolf]

How do you slug a chamber? Never heard of slugging a chamber but have heard of casting a chamber.

Here is one thread:
https://castboolits.gunloads.com/sho...hamber-casting

Good luck
Ron

[Dusty Bannister]

While Mr Wolf offers the thread on the best method, a quick and dirty way is to save some fired cases and try inserting your prepared bullet into the fired case mouth. If it slides in easily, there is sufficient throat clearance to use the bullet as you prepared it. If it is tight and resists entering the case mouth, the bullet needs to be sized smaller.

Keep in mind that there is a little spring back when the case is fired so this will build in a little clearance needed to release the bullet when fired. THEN try chambering a finished dummy round to make sure it chambers easily and can be extracted and you are ready to go.

[DougGuy]

Definitely fit to the throat.

[charlie b]

I always slug the throat to determine cast bullet dia. I size .001" over groove dia at the throat (this may be more than groove dia at muzzle).

I do not push the 'slug' all the way through the barrel, just enough to get a full imprint of the beginning of the rifling.. Throats tend to be slightly bigger than muzzle, especially on a rifle that has been fired a lot.

[TXCOONDOG]

This was very helpful and saved me some trouble down the road. Slugging the chamber, using once fired brass from my rifle and loading up some dummy rounds, .310" is the largest I can go.

Thanks all as I learned something new!!!

[Beerd]

make up a dummy round to check if the PC makes the bore rider portion of that bullet too fat to chamber.
..

[Walstr]

How do you slug a chamber? Never heard of slugging a chamber but have heard of casting a chamber.

Greetings: I truly 'slugged' my 1895GS bbl as opposed to 'casting'. I chose not to pour a metal liquid into my chamber to 'cast it', so here was my approach:

1-Obtain a few ounces of pure/soft lead
2-I poured this into my 45-70 case 'till about 1/4' from top
3-Whilst cooling, I got a 29/64ths drill bit [approx. .450" dia], drilled a few holes 'bout 1/2" deep
4-lined holes with alum foil & shaped this temp liner with a slightly smaller drill bit shank
5-heat up the lead & pour into these new "slug molds", wait to cool a bit
6-chamber my case filled 87% with lead; tie the lever so it doesn't pop open
7-remove a toasty "slug", drop it in
8-(oops, should be step #1?) wrap my 3/8" steel rod/all thread with elect. tape, etc.
9-push & lightly pound the rod, compressing & swaging the lead slug

Too many steps? Not on a dull Sat. night, with the prospect of actually being able to measure my chamber, in preparation of designing a new boolit mold! It was a satisfying process, a primitive but functional DIY takin' care of bisness.

Wally

[centershot]

Pound cast instructions from the Cast Boolit stickies:

https://castboolits.gunloads.com/sho...rifle-chamber)