Thread: Slow Powder, Heavy GC boolit, anyone got a ballistics calculator?

Drop a bullet in the breech, push it as far as it will go with a pencil, then stick a rod down the bore till it touches the bullet, mark the distance, tap out the bullet.
Replace it with a normal jacketed one and repeat. Is there a difference between the two marks? that will be your freebore.
Next measure the diameter of both rounds, any difference?
Measure the oal of a jacketed a cast round but also look at the ogive body junction, it may be that they are not seated deep enough and the flat nose is jamming in the leade.

rather than/easier than a jacketed round simple put cleaning rod through to bolt face,mark and compare with pencil pushed projectile mark to give you MAXIMUM OVERALL LENGTH for the round using that projectile...seat projectile in case measure keep screwing die in untill the above determined length is reached then nip say half a turn of the seating die off that length and should be good

Sensible and as you say quicker if you dont need to know the freebore

Cheers, will do that. Must say I did not expect this problem as this is a long, bore-rider nose (= lands riding) projectile with its fatter, rear driving bands tucked way back inside the cartridge neck.

The other, worn out, rifle did fine in the past with similar sized and seated 212 grainers, same external profile just RN not HP, same HXP neck aized brass. But not crimped.

I haven't had time to use the micrometer yet. Starting points of interest include projectile nose diameter and the loaded cartridge neck diameter. It was just the last 20 deg of bolt closure that were blocked and if it was just a matterof shoving the soft lead nose further into the rifling, then the camming action of the Lee bolt would have done that quite easily. But since the barrel DID retain the crimped boolit when I ejected the shell, maybe not.

The bullet nose diameter is .305" the lead is very soft so will jam in the rifling very easily, seat the bullet just off the rifling is the best option.

Originally Posted by shooternz

The bullet nose diameter is .305" the lead is very soft so will jam in the rifling very easily, seat the bullet just off the rifling is the best option.

It sounds like we have a mix up, Bob. You appear to think you sent me what I also thought I received, that is, something near a bore rider nose.

My boolits measure .313" both nose and band, and nose casting line marks are still intact along the nose, suggesting that something with a .313 nose and larger bands got sized down to .313 or .314. Weighed them, and found they are 213grainers, not 204 grainers. Explains how the boolit got stuck hard enough to yank it out of its deep seat in a sized and crimped neck.

Still need to examine the loaded cases though, as well as marks on the failed one.

So, update, what have I worked out.

1. The cases were at borderline max dimensions and resisted the gun going into full battery. Especially at the shoulders and rear half of the body. Neck sized only. Swapping between rifles, I realise they must have been fireformed in my No 4, which has a generous chamber. The 'H' SMLE brought to the range has the narrowest, being a late Australian rebarrel for target shooting.

2. The .313" nosed boolit is way too fat for most of my rifles' throats. Using Micky Duck's method shows I have to seat the boolit with its base ridiculously deep in the case to be off/at the throat (unsure if it reached the rifling). The failed boolit at the range really had the crimp dug into it as per photo. If I had not crimped it, it may have gone back into the case and if the case had not been too tight to fully chamber I'd have squeezed the trigger on it. Not sure how it would have gone. Lucky mistake swapping those cases or maybe it would have been a non event. The rear locking Lee bolt has the right kind of strength to manage overpressures, particularly its ability to "fail safely".

3. Good news it appears the loaded boolits WILL go in my shot-out SMLE which is the one that really needed them.

4. Need to manage my .303 case population apartheid better if I want to keep on only neck sizing.

5. "Youngest rifle in safe (1942 No 4) not always the smallest cases fireform". The generous .303 chambers were primarily a military design feature for reliable chambering, less from from sloppy machinery.

. Jammed boolit. No rifling imprint, just got shoved well back into the crimp before being left in the chamber upon ejection. Other boolit fresh out of the bag. .313" nose and bands alike, but it should still not give as much resistance as a copper/brass jacketed bullet. Someone please reassure me that assumption is correct.


Depth of seating worked out in shot out SMLE. Should go. Measurements indicate seating further out, but boolit laid out to show how the ones I've already loaded have been seated.

. H SMLE depth of seating. First measurement. Notice I coloured the case with brown ink and really gave chambering it a heave ho. Truly no go. The 'H' is a 1953 Australian rebarrel for SSA.

H SMLE depth of seating. Repeat measurement. Notice chamber conflict scratches again.

Looks like one of your barrels is a little higher than the majority, most .303 barrels are very worn in the throat I bought the fattest mould I could get for that reason

Originally Posted by shooternz

Looks like one of your barrels is a little higher than the majority, most .303 barrels are very worn in the throat I bought the fattest mould I could get for that reason

Yes, the 1953 H re-barreled Lithgow was maybe not fired with a lot of Cordite ammo.

And yes, your boolits will now revive my first (but worst gone) rifle for a new life of adventure. I just won't hang her on the wall yet. (-: