I am interested to buy a 230-245 grains gas-check large flat nose 308 bullet mold for a bullet to be used in a 20" barrel 1/10 twist single shot rifle at 1000 - 1500 fps, for short range pest control (deer size) and discreet informal target practice.
The Mountain molds Cast Bullet Molds online program suggest a maximum 230 bore riding 90%meplat, 0.800 nose bullet for 1/10 twist, a 245 bullet for 1/9, but I know nothing about theorical precision.
Do they stabilize or keyhole?The heavier weight gives more energy, and at 1000-1200 fps there is no big difference in traiectory. Someone may help me?

Haven't worked with any .308 bullets that havy...heaviest personally used was 202gr. a 1.19" OAL, but it did spin in a 1:12 twist.

Have delt a little bit with Mountain Molds...I'd tke them at their word.

Run your numbers through this on-line program and see if your design is stable at your muzzle velocity.
http://www.eskimo.com/~jbm/calculations/drag/drag.html

Bye
Jack

I would suggest looking at the data presented here. http://www.gmdr.com/lever/lowveldata.htm They don't have bullets as heavy as what you're talking about in .30 cal, but it should give you some ideas on powders and accuracy to be expected with reduced loads.

I wouldn't have a problem with using a 170 gr cast bullet on the deer we have locally and have some 311291s loaded in .30-30 for that purpose.

Think the original poster was limiting his velocity and wanted the heavy weight bullets to help bring energy levels up a bit higher...he'd rather have 230gr. at 1100fps than 170 at 1100fps.

Energy goes up with the square with veloctiy and only directly by weight...but given the same velocity, the heavy weight bullets do carry more energy and might pepetrate farther. "Might" becasue even if marginally stable in flight and grouping well, may become unstable in meat and not pepetrate as far as a lighter bullet that did stay stable.

Kind of agre with Paul5388, the standard bullets of 170-200gr. seem to work fine...would like a big wide flat point more than a few extra grains of weight.

I actually shoot those 311291 at close to 1600 fps with good accuracy. The velocity can go higher with the proper powders, but 2400 seems to perform good at these lower velocities.

If a wider meplat is needed, switch to the 311041 and increase weight a little too.

I actually shoot those 311291 at close to 1600 fps with good accuracy. The velocity can go higher with the proper powders, but 2400 seems to perform good at these lower velocities.

If a wider meplat is needed, switch to the 311041 and increase weight a little too.

Here is where a flat point can help..assuming you want the heaviest bullet you can spin in that twist and at those speeds, it's mostly length that enters the equation. Flat points are shorter for the same weight. Have to balance the length of the bore-riding section with the length of the full diameter section and factor in the chamber length and case neck length...but idealy (for your stated use) you'd want whatever bullet seats to the bottom of the case neck, snuggles the full diameter section right up to the rifing origin, and has a OAL length that will spin true with that twist barrel.

SO..a long "free bore" to rifling would allow a longer full diameter base section and a shorter nose section (which results in a shorter OAL of the bullet for a given weight)...and a short throated rifle does the reverse.

Then you have the problem of feeding...some bolt actions will refuse to feed wide flat points (Mauser-types types being rather picky about this due to the flat faced barrel breech).

Have shot Lyman #311299's from a 1:12 wsit barrel down to aproximately 600fps...sure, they strung up and down by good foot and a half, but each and every one struck point on (kind of like lawn darts, they were about 1/2 driven into rail road ties...could latch onto them with pliers and pull them out). Was just a test, and it proved the bullet was stable in that twist, so i moved on to more reasonable loads.