Cast Bullet 300Blk or 308win

Rivardo

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I'm trying to decide which caliber I am going to cast bullets for. The 300Blk seems very suitable. Or am I missing something and would it be better to go with a 308win. 1-7twist for the 300 and 1-10twist for the 308. Bolt action 700.. ... Do I give anything up with the 300Blk or is it just more efficient than a 308win (with cast bullets)? I would like to use the heaviest supersonic bullet I can. Noe 247 308win 1-10 twist might not work.. . .. maybe 180gr in a 300blk 1500-1600fps. Powder coated no gc. Any advice from you veteran bullet builders would be awesome!!
 
With no check those speeds are a little on the optimistic side of things.

whats a reasonable velocity? also seems that the 300Blk would be a better choice then. faster twist and the capacity of the 308win is not really needed? Maybe just stick to heavy subsonics in the 300.. .
 
1300-1400 is about all you are able to get from non checked bullets. I check mine and have had them to 1700 ish. Never got to try them higher yet. But there are guys checking them and shooting them at jacketed speeds.
 
I was under the impression that you can push powder coated boolits to 2200-2400..... I’ve never tried PC, so I have no exp.

I use GC on 180gr pills cast with a lee mould, iirc, accuracy out of a 308 bolt gun (1:11 twist) is acceptable at 100y, velocities are in the 1700 FPS range. I wouldn’t worry about the chambering of the rifle, it won’t matter, velocities will be close to the same, and the twist won’t matter.....
 
I was under the impression that you can push powder coated boolits to 2200-2400..... I’ve never tried PC, so I have no exp.

I use GC on 180gr pills cast with a lee mould, iirc, accuracy out of a 308 bolt gun (1:11 twist) is acceptable at 100y, velocities are in the 1700 FPS range. I wouldn’t worry about the chambering of the rifle, it won’t matter, velocities will be close to the same, and the twist won’t matter.....

A 300blk can shoot a 180gr bullet 1700fps? Also do you think a 1in10 twist would stabilize a 247gr bullet
 
I was under the impression that you can push powder coated boolits to 2200-2400..... I’ve never tried PC, so I have no exp.

I use GC on 180gr pills cast with a lee mould, iirc, accuracy out of a 308 bolt gun (1:11 twist) is acceptable at 100y, velocities are in the 1700 FPS range. I wouldn’t worry about the chambering of the rifle, it won’t matter, velocities will be close to the same, and the twist won’t matter.....

I tried pushing 7mm RM cast powder coat to those speeds, couldn't hit the side of a barn.
 
I am going to try gas checked powder coated next, I know its not the rifle as it shoots great groups factory ammo.

All I use for rifle is checked bullets. I know mine are good to at least 1700fps. Ordered a new mold for the 30-06 it is a sp mold so should feed better then the fp I cast for 30wcf
 
All I use for rifle is checked bullets. I know mine are good to at least 1700fps. Ordered a new mold for the 30-06 it is a sp mold so should feed better then the fp I cast for 30wcf

I have shot a lot of powder coat with out gas checks, 300 blackout (230gr subsonic ), 45-70 (405gr 1500fps), 40sw,9mm,45acp and even 44mag at around 1400fps but as soon as i hit 2000+ accuracy is gone.
 
A lot of Cast Bullet Association winners use 30BR or 308 x 1 1/2" with approx. 200gr gas checked bullets at 1900 to 2100fps. If accuracy is your goal, that should be a good place to start. If plain base bullets are high on your list, probably .32 Miller Short.
Grouch
 
I've been reloading for years, using another guys cast boolits with gas checks in 308. The accuracy is fantastic, at around 1600FPS I get usually under 1.5 inches.

I figured why not get into casting myself. The OP asks some interesting questions about gas checks, I know you use them for accuracy, but I've never looked into how powder coating adds to subtracts from the equation. Is there a general consensus on whether powder coated bullets let you push them harder at the cost of accuracy, or does it improve things all around?
 
I've been reloading for years, using another guys cast boolits with gas checks in 308. The accuracy is fantastic, at around 1600FPS I get usually under 1.5 inches.

I figured why not get into casting myself. The OP asks some interesting questions about gas checks, I know you use them for accuracy, but I've never looked into how powder coating adds to subtracts from the equation. Is there a general consensus on whether powder coated bullets let you push them harder at the cost of accuracy, or does it improve things all around?

generally speaking, PC should allow you to shoot higher velocity than non PC, while maintaining accuracy - to a point. If you go high enough PC bullet accuracy will go to hell too.

As a rough rule of thumb, gas check cast bullet can go 1700-2000 fps before leading, PC bullet 300-400 fps faster, maybe more.
 
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I wonder what part of the recipe causes accuracy to go down versus jacketed, maybe the bullet starts to shear after a certain speed, making it inaccurate?

Someone should troll hard and powder coat some 50cal roundballs for their musket. Post pictures all over the black powder forums
 
Well, lots to talk about here that has been discussed that I want to add my two cents to. As to the OP's question I have neither a 300 BO or .308 Win. but I do have several semi auto rifles in 7.62 x 39 as well other 30 cal. rifles one being a lever gun in 300 Sav. which was the parent case for the .308 Win. as well as several bolt gun in 7.62 x 54r. In those rifles for 1400 fps. an above I shoot cast lead bullets that are gas checked and either use traditional lubes or they are powder coated, these bullets generally weigh from 155 to 215 grs. For anything below 1400 fps. I just leave the gas check off for most applications as those loads are for general purpose plinking or small game hunting under 50 yds. In general bullets designed to use a check will shoot more accurately with the check installed once you reach a certain velocity / pressure.

One bullet that I see showing up on a regular basis that is used in both the BO and .308 is the Lee .312" 155 gr. SP bullet sized accordingly and either traditionally lubed or powder coated, one of the bullets I use in all my rifles is the Lee 160 gr. TL gas check bullet that I powder coat an size accordingly, I've pushed this bullet up to around 1900 fps. with excellent accuracy, haven't really tried to push it any faster but it's in the works when time permits. There is more that goes into shooting a cast bullet at or near jacketed bullet velocity in some calibers than just casting a bullet, slapping a gas check on it with some form of lube and using X powder to get up to jacketed velocity and still get good accuracy. I plan on getting a copy of this mold the 30 XCB which was designed for HV cast shooting to try in my newly acquired 30-06, It will probably be in the early spring of next year before I can get all the ducks in a row on that project. The bullet will be useful in my 30-30 and 300 Sav. as well.

Gas checks serve several purposes, one is that they help protect the base of the bullet agents gas cutting which can be caused by velocity induced defects on the base or defect caused by the rifling itself to the base of the bullet. These defects allow the high pressure gasses to get around the bearing surface of the bullet and burn off the lube which is one of the many causes of leading, individual get leading with powder coated bullets just as easily as non coated bullets. Gas checks also give extra grip to the bullet especially in those with micro groove bores or polygonal rifling, the copper or aluminum checks have a higher BHN that the hardest suitable cast lead alloy you can make. The added grip keep the bullet for slipping or skidding on the rifling which aids in stability an accuracy, checks are not always needed but at some point along a given point when velocity / pressure overcomes the bullets alloy strength the gas check comes into play.

For me powder coated bullets in rifles and especially in handguns was a game changer, PC is a lot less messy, leave my seater and sizing dies an hands cleaner and allows long term storage of bullets ready to load or stored or loaded that are not affected by heat or cold as some types of traditional lube would be. Leading has never been an issue for me in my handgun and rifles so that was never a problem powder coating had to solve, it just made things easier. I treat PC as a form of lube which forms a thin jacket of material that has a few added benefits over traditional lube but it doesn't make your bullet magic. All the things that would apply to traditionally lubed cast bullets still applies to make them shoot well PC'ed or not.



Some good articles.
https://goodsteelforum.com/forums/t...oot-cast-bullets-with-precision-and-accuracy/

https://goodsteelforum.com/forums/topic/high-velocity-cast-bullets-what-i-have-learned-and-observed/

Some good videos.

https://youtu.be/dJS5LUvFJCA

https://youtu.be/l9VDouNYi7A
 
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