Outdoorfan, there are different alloys of cerrosafe, those which shrink, expand, or are neutral. You might want to find out which your 'smith is using. Their website will have info on percentage of shrinkage or expansion for each alloy so you can figure actual size.
As for full-steam velocities, I experimented with an 8x57mm, shooting a PP'd H&G .312 cast version of the 173gr spritzer service boolit. As a bare boolit, accuracy went south beyond 1500fps or so in various .30's, which is typical of long-ogive cast, but PP'ing it decreases its unsupported ogive length and increases its bearing surface. It gives me 2" at 100 yards over 48gr of Rel 19 in the 8x57. Other .30 molds exhibit the same effect when patched to the 8mm throat. I vote for PP because it increases the range of usable (soft) alloys and the velocities they can be driven to. For your purposes, might I suggest the Lyman 311407, a 180gr Loverin design amenable to easy sizing to finished diameter after patching and having the advantage of a meplat of .08 or .10, from the look of it. Another candidate is 311041, allegedly 173gr, but mine cast of WW are 180gr. The bore dia. nose handily patches up to groove diameter in a .30, thus increasing engagement length to approx. 80% of physical length, but which also means adjustments in OAL. These are not heavy-for-caliber, but they do work well.
The paper I use is 100% cotton drafting vellum available in art supply places or online, usually .0025", two wraps for .30, three for 8mm. Strips are cut from the narrow edge (the end) of the sheet to provide stretch when wet and shrinkage on drying. I no longer use a twisted tail, instead patching from the heel on a GC design to half way up the ogive and wiping the last 1/2" end of patch with wood glue (gluing paper to paper) to keep it in place. Shrinkage below the bottom driving band prevents the patch from slipping when seating. Gas checks can be applied, but do not seem to improve accuracy. With a worn throat, they will allow the boolit to be seated a touch farther out and still have good retention in the case.
Last edited by yeahbub; 01-10-2018 at 06:17 PM.
I didn't know that there are variations with cerrosafe.
Thanks for your suggestions and tips!
Gas check and powder coating should give you what you are after. I know it can in 308W. You will probably need to add some copper to keep bullet together due to spin rate but accuracy does drop off the higher velocity you go past the optimum speed. People all over the world have used cast bullets for every animal out there so with the proper fit to barrel and chamber you should be able to do the same thing. Get the fit, its a key.
Outdoorfan - Always go to a vendors loading data website instead of posts guessing what you want.Full jacketed in my mind is ~2700 fps from a 180 grainer in 30-06. Maybe 2500-2550 from a 200 grainer.
To this end - Hodgdon/IMR loading data website rifles - put your bullet weights in and you'll get a lot of TESTED information ... http://www.hodgdonreloading.com/data/rifle
For teasers, the fastest velocity of a 180gr bullet is:
180 GR. SIE SPBT
Hodgdon
Suprform
.308"
3.300"
54.0
2,628
46,200 PSI
59.7
2,840
57,600 PSI
Regards
John
Here's an update. ShooterAZ graciously sent me some of his 195 grain boolits (http://www.accuratemolds.com/bullet_...=30-190P-D.png), along with some greenbar paper.
After figuring out how to roll a decent patch (I seem to like the cigarette roller), I fired some test rounds. Absolutely no load development here. The best results were with IMR 4350. 53 grains with a 1x1" tuft of dacron over the powder. Velocity is around 2700 fps. I fired two 3-shot groups of that load at 100 yards on two different days. 13/16 & 1 3/8". At 200 and 300 yards, although testing was not conclusive by any means, it seems that the groups were starting to show some inconsistencies in random fliers/disbursement. I did get minimal chronograph readings down range to suggest that maybe this boolit has around a .235 ballistic coefficient. However, I think the 10 bhn or less that the boolits are that I tested, might be too soft to survive the acceleration forces to keep good accuracy past 100 yards, at least at the full pressures that I tested them at.
Overall, I would say a very good initial success. Thanks again to ShooterAZ for making this possible for me to test.
Now I have a heavyweight mold on order from NOE.
Don't let your patch ends overlap
and a cardboard wad on the base of the bullet may help as well.
Anything p-dawg said is pretty well gospel.
I tried hard to get a close fit, but no overlap. That cardboard wad, is that boolit diameter? Otherwise, won't that be cause for concern trying to get through the bottleneck of the neck? Just wondering.
Snug neck size and supported in the neck by filler if there is room.
Otherwise I wouldn't do it either.
Stops the wad from getting below neck and causing troubles.
It protects the base from peening from the gunpowder hitting into it upon ignition.
I have used hard wax wads too.
Sometimes it helps sometimes not.
I've used wads under the patch.
Rest In Peace My Son (01/06/1986 - 14/01/2014)
''Assume everything that moves is a human before identifying as otherwise''
How did that work for you, 303Guy?
Shooter AZ; Would you think your lead is aprox 20-1 or closer to ww? I have plenty of 20-1 and just picked up a pp 301 mould.
I use either range lead or 96/3/1. Both are pretty darn soft. 20/1 should be good to go.
Outdoor fan, please keep us posted on how that new mold works out for you. That is one heavy dude.
Just ordered a .301 and .310 body size dies from NOE for my pp bullet. Have some 16# cotton paper that patches to .314 and will maybe size down to .310 or so ??? All my BP paper is too thin but might work with three wraps? Anyone try that?
We're getting so much snow these days that I can no longer access the field that I've been shooting on. Lol!
Another issue I had trying to size those cruise missiles down is that the .285 Lee die that I opened up wouldn't size such a long piece of soft lead down without bending the boolit. Then I basically ruined the die by opening it up too much trying to find what size it could size the missile down to without distorting it.
Now I have two new .285 Lee dies sitting on the bench that I need to very CAREFULLY open up to .3015 or so, and maybe .305. I already have a .308 on hand. This may not work, but I'll try.
Is there a secret to polishing the die after using emery cloth to open it up?
Secret to polishing (anything):
Progressively finer grits, alternating directions between each grit.
I give loading advice based on my actual results in factory rifles with standard chambers, twist rates and basic accurizing.
My goals for using cast boolits are lots of good, cheap, and reasonably accurate shooting, while avoiding overly tedious loading processes.
The BHN Deformation Formula, and why I don't use it.
How to find and fix sizing die eccentricity problems.
Do you trust your casting thermometer?
A few musings.
Thanks. I did somehow manage to hone these dies out and get some useability (is that a word?) out of them.
Here are two missiles, one at maybe 9 bhn and other at maybe 12-14 bhn. They sized down fine in three steps. .308, .305, .302. I slightly overdid the .302. I was shooting for .3015. I think/hope it will be fine.
I have no idea when I'll actually be able to shoot them.
BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
BR | Bench Rest | M | Magnum | RN | Round Nose |
BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
GC | Gas Check |