advice for .45-70 cast boolit lots of questions

[cudatruck]

Ok, where to start... i have starline once fired cases (in my rifle) they measure only .458 inside the case mouth. were my loads too light to fully expand the brass? can my rifle chamber be that tight? I have some cast 465 gr sized to .458 i think from oregon trail they measure about .456 and fit nicely into the brass. I bought some hunters supply from midway 405 gr sized .459 they measure about .457-.458 and will not start into brass i would have to expand. Also these hunter supply bullets vary GREATLY in weight! none are 405. most are 391-392 gr. these are plain base, i don't think they are desgined for GC. I have a couple of samples from a member here they measure .458 and again won't start into fired brass. Do I need to get a sizing die to bring them down to .457? .458 and expand brass? load a couple really hot to check brass expansion? what's up with the inconsistent weights? None of the bullets i have weigh what they are supposed to, is this common? how much expansion should be normal on the case from firing? any advice is appreciated, thanks, Mike.

[Spokerider]

You have many questions............
 
Others will jump in here for sure, but, here are a few suggestions.....
 
Slug the bore. This will tell you what diameter the boolits need to be. They can vary from being equal too the bore diameter, to .001-.002" over. This will just be a starting point as far as obtaining best accuracy however.
Wanna see if the larger boolits will chamber? You can try sizing the brass in your ?45 70? sizing die, and seating a .458 boolit into the brass. This is a dummy round, so no powder, no primer. Do not crimp. Leave the boolit proud and don't seat to the crimp groove. Gently push the dummy round into the chamber to see if it will chamber. It may hit hit the lands before it fully chambers.....that's good. Ease the boolit deeper into the case and try again. If you can chamber the dummy round with the boolit .010 off the lands, then it will shoot. Whether is is the correct fit for your bore is another matter.......you're back to slugging the bore to get this info.

[45-70.gov]

get a cheap  LEE universal flareing tool
http://www.midwayusa.com/product/140461/lee-universal-neck-expanding-die
i think this is it


i  also chamfer the inside of the case mouth.....WITH ALL LEAD BULLETS


lack  of flaring  and no inside chamfer  will damage/shave  lead bullits

[twoshooter]

Stuffing ANY straight wall case with a cast bullet is the same, be it a 32 H&R or a 500 S&W. You need either a slight bevel on the bullet, or a little flare on the case mouth to start. Also, if you are not using a high pressure load the case may well not be stretched  that much. Do you have any soot or blacking around the case mouth ?

[cudatruck]

no soot or blackening, i felt the rounds i fired were pretty strong, surely should have been strong enough to expand the brass to fit the chamber. I understand the flare, but have been following other guys postings about cast with these rounds saying" de cap prime charge seat a bullet and shoot". they have even posted about going up in size of the boolit to fit the brass as long as it will chamber. my brass seems to small after firing to do this. i will have to get around to slugging this bore and maybe make a chamber cast to see whats going on.

[45-70.gov]

you will find the bore is  constricted just past the chamber


my  experience has been
if they don't shave  they won't hold the bullet
and if they shave they need a flair


i shoot  mine also in a marlin   with a tube  so bullits must stay put

[mechanic]

Sounds like you need to do a chamber cast on this one.....
Ben

[shot1]

Your chamber sounds to be OK. Yes a case stretches when fired to fit the chamber and seal the gasses and allow the bullet to be released. Then the case contracts, shrinks back some, to allow you to extract the case. To load these cases if you are shooting them in a single shot you should part size the case. By this I mean you need to size the neck portion of the case down some. I do this with a FL size die leaving some space between the die and the shell holder. You can smoke the neck of a case with a candle and tell how much of the neck you are sizing. After sizing the neck down you then need to expand/bell the case mouth just enough to except your bullet so it does not shave any lead off the bullet when seating. I would then seat all your bullets to the over all length you need then as another step go back and and use the crimping part of the seating die to just smooth the bell of the neck even with the bullet. You will need to experiment some though. Some load shoot better with a firm crimp placed on the case to bullet.

If you are loading for a repeater rifle you should FL size all your cases as well as place a good crimp on the case mouth to the bullet.

You do need to slug your bore to see what diameter bullet you need. Mostly you will need 1 to 2 thousands larger diameter bullet than your bore.

The reason that your bullets weigh differently is because of the mix of metals used to make them. Different amounts of lead, tin etc. will make a bullet weight different. If you don't keep your mix fluxed and mixed up well during your casting the metals will separate and thus make your bullets not consistent. Most of the bulk bullet makers don't take the steps necessary to make precision cast bullets like you can do for yourself.

I can cast 400 to 500 gr bullets that do not very over 1/2 gr max between them but it takes paying attention and taking your time.

The base of the bullet is very important to accuracy. Keep everything sharp and smooth.

It will help you to read a good reloading book and books on casting bullets to learn what you need to know.

[cudatruck]

ok, thought i was clear about it but will try again. the inside of the neck AFTER firing measures .458. the bullets are commercial bought cast. they are LARGER than .458 or right at .458. Why would i size the brass down from here to turn around and expand? I will chamber cast this rifle to see whats going on. I want to find a bullet that fits the fired case mouth without sizing and still chambers like gcrank1 is talking about all the time. I expected the brass to come out at a larger diameter NOT .458. going to slug the bore too, hoping i do not have a tight chamber with an over bored rifle! this barrel was bought new as a complete gun. the sights are wrong from the factory and now this. If i can not correct this simply i will be sending the damn thing back.

[cudatruck]

Thank you guys for the responses. I think you have answered my question about bullet weight.... the commmercial cast bullet manufactures have lousy quality controll? in one box of bullets they are varying quite a lot. might not be a problem in 400gr bullet but seems like with lighter ones the variations would certainly be problem. I will weight sort these and try them out. bought them because they were affordable and available. guess you get what you pay for.
 
Bullet weights vary from 385.5 grains to 396.6 grains in one box of store bought listed as 405 grain bullets. Were they leaving room for a gas check? 10 grains of variation? wouldn't this chang POI? how can you work up a load with these? is a 2.5% variation in weight acceptable? paid for 405s and got 395s should i feel cheated? can you tell i'm new to cast bullets?
 
If it were you would you load these with powder charges from a book listed for 405s?

[45-70.gov]

i have never measured a case mouth....maybe i should


they  always  woked foor me...unless they shaved lead
then  i just flared the moth some more


i wouldn't be too concerned  about the wieght
but if they don't shoot good...that will be one variable to re-visit