Rifle Hardness

[pearcetopher]

Hi guys, Ive casted lots of pistol boolits with no issues but I seem to have trouble casting rifle bullets.

I tried the lee 309-170-flat and the lee 311-160-rn both with gas checks attached and I find that I can only get my groups within two inches at 100 yards if they are fired at below 1300 FPS in my 300 win mag.

Ive slugged the barrel at .3085 and I am using a .312 sizer that is not touching the boolits, only attaching the gas checks.

I am using red dot as my powder as I have 8 lbs of the stuff and these boolits are baked in the oven and come out at a BHN of 20

whats going on?

I see on here people push their gas checked boolits up to jacketed velocities but there sjust no way my stuff would ever work like that

[454PB]

Are you seeing any leading? Have you measured the boolits to see what diameter results when sized and not touching?

Every rifle has it's own preference for an accurate load, yours may want something different. I'd try a slower powder and see if grouping improves.

[geargnasher]

Hi guys, Ive casted lots of pistol boolits with no issues but I seem to have trouble casting rifle bullets.

I tried the lee 309-170-flat and the lee 311-160-rn both with gas checks attached and I find that I can only get my groups within two inches at 100 yards if they are fired at below 1300 FPS in my 300 win mag.

Ive slugged the barrel at .3085 and I am using a .312 sizer that is not touching the boolits, only attaching the gas checks.

I am using red dot as my powder as I have 8 lbs of the stuff and these boolits are baked in the oven and come out at a BHN of 20

whats going on?

I see on here people push their gas checked boolits up to jacketed velocities but there sjust no way my stuff would ever work like that

What's going on is your loaded cartridges don't fit the rifle and your powder is too fast. I don't know what your alloy composition is, but a heat-treated hardness of 20 is good to at least 2300 accurate fps in a .30 caliber, in some instances more.

Gear

[YunGun]

While I don't own, shoot or reload for a 300WM, I've been playing with cast in an '06 for awhile now & I'd bet that all of the people you're referring to are using MUCH slower powders to achieve jacketed velocities.

RD is a very fast powder, which is going to limit your max velocity with accuracy.
You should be able to both gain velocity and improve accuracy somewhat by moving to a slower powder.

The faster pistol/shotgun powders are rather limited regarding powder charge weight & subsequent velocities due to their rate of pressure build-up; while they make great, economical 'mouse-fart', target or plinking loads, they'll reach max pressure before you achieve jacketed velocities.

Reminds me of that old adage about 'You've got to slow down to go faster!'.....

[KYCaster]

How well does your boolit fit the chamber?

Jerry

[btroj]

What's going on is your loaded cartridges don't fit the rifle and your powder is too fast. I don't know what your alloy composition is, but a heat-treated hardness of 20 is good to at least 2300 accurate fps in a .30 caliber, in some instances more.

Gear


Powder and bullet choice are very critical to get over 2200 fps with accuracy, aren't they Gear?

With red dot you are kicking the bullet hard and fast, this deforms the bullet and accuracy goes to hell. Red dot is a fine powder for low end velocity but it won't do the trick for much over 1500 fps.

[Scharfschuetze]

In addition to the powder and alloy comments above you might consider the following:

With the short neck on the 300 WM, is your boolit with GC protruding below the neck?

Have you tried seating your boolit out to touch the rifling?

Are you expanding your neck enough to not damage the .312" diameter of your boolit when you seat it? A good inner diameter would be .310" for your neck.

Were I you, I'd consider all of the above and also pick up (while you can) a can of IMR 4759 powder. It is pretty bulky and is about right for cast boolits in larger cases (like your 300 Magnum) for moderate to higher velocities with cast boolits.

[pearcetopher]

ive tried all those things, the load data im using is for the exact rifle, bullet, weight, and powder.

It goes from I think 15 grains of red dot to 22

I can only pull two inch groups at 13 grains so why the f isnt the load data correct it shouldnt matter powder choice because I have data for this EXACT powder

[Larry Gibson]

the load data im using is for the exact rifle, bullet, weight, and powder

Not sure where that data comes from(?) but Lyman's #3 CBH gives 15 to 18 gr of RD for cast bullets in that weight range. Still, as mentioned by others, that is too fast a burning powder for the level of velocity with accuracy you apparently desire? Your accuracy at and below 1300 fps is about right for that powder and cast bullets. I would add to the suggestion to use a slower burning powder and you might consider a Dacron filler with load density being less than 80%. The recommended 4759 would be a good one to try. Another consideration would be a heavier bullet with a medium or even slower burning powder.

Also while the groove diameter may be .3085 the important diameter to fit is the throat diameter. You might simply use a .310 or .311 sizer on the bullets to uniform them and give a probable better fit in the throat. Also as mentioned you want to keep the GC in the case neck if possible.

What alloy are you oven heat treating for a BHN of 20?

What lube?

What accuracy level do you get with your best jacketed load using the same number of shots (assuming 5 minimum and best at 10) at 100 yards?

Larry Gibson