30 BR Long Range report

[dtknowles]

you are absolutely right, jacketed bullets used are around 125 grs. and barrel twist is approx. 17"....I thought you were chasing cast boolit accuracy, something totally different

I am but my rifles twist rate is 16:1. I think I need to keep the bullets under an inch long. The recoil would be less with a lighter bullet too.

Why is cast bullet accuracy something totally different and why would cast bullet shooters shoot heavier bullets then jacketed bullet shooters?

Tim

[charlie b]

Why not as accurate? If you can answer that you'd win a lot of matches Lots and lots of opinions on the topic.

Heavier bullets? I use them because at lower velocities the heavier bullets will stay supersonic to longer ranges. I will use 'std' weight bullets if shooting at shorter ranges (100-200yd).

Why lower velocities? My barrel is a 1:10 twist .308 and I lose accuracy when I push bullets past ~2000fps. Why? Again, if you could answer that you could probably 'fix' it and shoot more accurately than most. Yes, I can shoot to 2500fps and maybe even more but the accuracy falls off. At 2400fps I am shooting 3MOA vs 1MOA at 1900fps.

So, with a slower twist barrel you should be able to push velocity quite a bit more than I can and still maintain accuracy. The only way to know is to shoot some bullets.

The only caution is that when you increase velocity you need to take more care in which lube you use.

[bruce drake]

interesting thread and I've subscribed to it since I built an AR15 upper in .30BRX with a rechambered 1-8" barrel that used to be a .300BLK. I'm looking at using the heavier 150-200gr bullet weights to replicate 30-30 Winchester level loads.

Bruce

[dtknowles]

Why not as accurate? If you can answer that you'd win a lot of matches Lots and lots of opinions on the topic.

Heavier bullets? I use them because at lower velocities the heavier bullets will stay supersonic to longer ranges. I will use 'std' weight bullets if shooting at shorter ranges (100-200yd).

Why lower velocities? My barrel is a 1:10 twist .308 and I lose accuracy when I push bullets past ~2000fps. Why? Again, if you could answer that you could probably 'fix' it and shoot more accurately than most. Yes, I can shoot to 2500fps and maybe even more but the accuracy falls off. At 2400fps I am shooting 3MOA vs 1MOA at 1900fps.

So, with a slower twist barrel you should be able to push velocity quite a bit more than I can and still maintain accuracy. The only way to know is to shoot some bullets.

The only caution is that when you increase velocity you need to take more care in which lube you use.

It might not be the total answer but there is no more accurate accurate bullet than the bench rest bullets made by the likes of Berger or BIB. They are stronger and more precise than any cast bullet.

I understand heavier bullets for long range shooting but why do the shooters who shoot at 100 to 200 yards shoot heavier bullets? Even a flat nosed 30 caliber 125 gr. bullet starting out at 2000 fps is still going 1300 fps at 200 yards. I don't see much to gain by pushing the velocities higher. 2000 fps is plenty for shooting at 200 yards. Hey, they are the guys winning the matches but why do they shoot those heavy bullets?

[charlie b]

Not all of them do. Most do, but, some do not. Found two matches won by guys shooting 175gn bullets.

It may be as simple that a heavier bullet bucks the wind better. Can be important on a windy day. Just another trade off to think about.

[MT Chambers]

I don't approach it that way, to me results with j-word bullets is of no consequence, lead boolits cast of mostly linotype, with a little tin, pushed between 1500 and 2000 fps. gets me where I need to be. Light, pointed, cast boolits have never shot well for me, but give me my NOE copy of Saeco #315 in my .30 Br. and I'm there. Same thing with my .308 but with an Eagan MX-3, or my 300 B.o and 311466 and I'll go from there.

[Larry Gibson]

I am but my rifles twist rate is 16:1. I think I need to keep the bullets under an inch long. The recoil would be less with a lighter bullet too.

Why is cast bullet accuracy something totally different and why would cast bullet shooters shoot heavier bullets then jacketed bullet shooters?

Tim

Keeping bullets under 1" in length is what I found also with the 16" twist in my 30x60 XCB. However, I've more case capacity than you. I found the shorter old Lyman Loverin design 31465 at 122 gr to be a very good and accurate bullet for low end velocities [under 2000 fps] that I got a 4 cavity NOE mould for it. It's also an excellent bullet in numerous other 30 cal rifles even with faster twists.

[dtknowles]

Keeping bullets under 1" in length is what I found also with the 16" twist in my 30x60 XCB. However, I've more case capacity than you. I found the shorter old Lyman Loverin design 31465 at 122 gr to be a very good and accurate bullet for low end velocities [under 2000 fps] that I got a 4 cavity NOE mould for it. It's also an excellent bullet in numerous other 30 cal rifles even with faster twists.

Larry, thanks again.

Tim

[charlie b]

It might not be the total answer but there is no more accurate accurate bullet than the bench rest bullets made by the likes of Berger or BIB. They are stronger and more precise than any cast bullet.

I understand heavier bullets for long range shooting but why do the shooters who shoot at 100 to 200 yards shoot heavier bullets? Even a flat nosed 30 caliber 125 gr. bullet starting out at 2000 fps is still going 1300 fps at 200 yards. I don't see much to gain by pushing the velocities higher. 2000 fps is plenty for shooting at 200 yards. Hey, they are the guys winning the matches but why do they shoot those heavy bullets?

Bench rest jacketed and solid bullets are a good comparison. They perform better than standard jacketed due to their perfection in size, shape and consistent density. Precision shooters will 'custom form' commercial bullets to get consistent ogives, which give consistent seating depths and jumps to the lands. Cast bullets are worse in most regards in those same areas. I size some of my bullets twice, once for the driving bands and once for the nose section, for the same reason. But, I cannot guarantee that I get all the voids out of my casts.

As to heavy bullets, I have been thinking about it a bit more (and that is a dangerous thing ).

I wonder if the heavier bullets give more consistent powder burn than the lighter ones at the lower velocities? I know that the cast bullets I have shot sometimes are picky about the load depending on the powder and some powders are a bunch better, especially when case capacity is much larger than the powder charge. Theory would be that the heavier bullet produces a larger pressure spike. Many powders are designed for higher pressures and this may just put them closer to the designed burn rates. One of the things I do is seat the bullets so they jam into the lands. Gives a bit of initial resistance to the powder pressure. I know some who apply a slight crimp to the bullet instead.

I am going to go back and look at some of my velocity data and see if I can come up with something.

[dtknowles]

Bench rest jacketed and solid bullets are a good comparison. They perform better than standard jacketed due to their perfection in size, shape and consistent density. Precision shooters will 'custom form' commercial bullets to get consistent ogives, which give consistent seating depths and jumps to the lands. Cast bullets are worse in most regards in those same areas. I size some of my bullets twice, once for the driving bands and once for the nose section, for the same reason. But, I cannot guarantee that I get all the voids out of my casts.

As to heavy bullets, I have been thinking about it a bit more (and that is a dangerous thing ).

I wonder if the heavier bullets give more consistent powder burn than the lighter ones at the lower velocities? I know that the cast bullets I have shot sometimes are picky about the load depending on the powder and some powders are a bunch better, especially when case capacity is much larger than the powder charge. Theory would be that the heavier bullet produces a larger pressure spike. Many powders are designed for higher pressures and this may just put them closer to the designed burn rates. One of the things I do is seat the bullets so they jam into the lands. Gives a bit of initial resistance to the powder pressure. I know some who apply a slight crimp to the bullet instead.

I am going to go back and look at some of my velocity data and see if I can come up with something.

I don't know if what you are talking about is why some shooters use heavy bullets but I think most of what you said is helpful. I have had better luck with bullets jammed. I have a smaller capacity case so load volume is high but I expect that the right powder would make a difference.

I actually think the load I am using is going to be very accurate and I think the problem is my bench rest technique is causing fliers. I am often seeing three out of 5 rounds in one hole. I noticed some deep scratches on the bottom of the forearm of my rifles stock. Something is out of whack with my rest. The recoil movement is violent enough that the front bag is being compressed to the point that the stock is hitting the screws that hold the front bag in the rest. I need to pump up the front bag and shoulder the gun when shooting.

Tim

[charlie b]

LOL Yep, the shooter is to blame for a lot of stuff

I still have a consistency problem. Especially when working on a really small group, like 1/2" at 200yd. Get 3 or 4 really close and then I mess one up. Usually jerk on the trigger, but, sometimes not 'setting' the rifle right. Same with 10 round groups. Get 6 or 7 in a tight little group and then I get overconfident and don't concentrate.

But, sometimes with cast, I get a flier I can tell is not me.

I think your description means you need to fix your equipment first.