I once owned a Howa Lightning 1500 in .223 Remington and currently a CZ 527 Lux/Americsn which share a common problem. The twist rates in both barrels was 1x12. Accuracy was so-so with 50 grain boattails with H335, Winchester 748, AA2230 and a couple of other powders. The same was true with Hornady V-Max in 550 grain, or any .22 cal bullet with a boattail. I did find one load with Winchester 748 and 55 grainers, but I had to drop the velocity to around 3,150 fps. One day I inadvertantlly bought some flatbased bullets by mistake and figured what the hell, I'll load'em up and see what happens. Worked up first to see if my pressures were okay, then tried fairly much the same loads I had been shooting with the boattails in the 50 gr Hornady SX. Right out of the gate I began getting groups, five shot groups, going into quarter inch size, but mostly about .30 inch size. Shifted to the 55 grain bullets and hit the same scenario. I now just shoot flatbased bullets. But what gives on the boattails. Why do boattails seem to shoot with less accurately than flatbases? Is it possibly due to the barrel twist? Anyway, thought that at least I would ask. Thanks for your time ... Tom Purdom

quote:

Originally posted by 7x57mm:
But what gives on the boattails. Why do boattails seem to shoot with less accurately than flatbases? Tom Purdom

FYI

You probably will get a more correct answer from the BR group. roger

Tom

It depends on the gun. I have some that shoot the flat base bullets best and conversely some have shot the boat tails better.

I don't really worry about using BT's unless I plan on shooting near 400 + yards because that is basically where the higher BC really starts to make a difference.

The Hornady SPSX bullets are very reasonable but don't sell them short. I shoot a lot of them and they are as good as it gets in my .222 using RL7.

quote:

Originally posted by 7x57mm:
Why do boattails seem to shoot with less accurately than flatbases? Is it possibly due to the barrel twist? Anyway, thought that at least I would ask. Thanks for your time ... Tom Purdom

While rifles are different, many will shoot FB bullets better because BTs move mass outward which takes more rotational speed to stabilize.
Especially when you are pushing the envelope with the twist to weight ratio.

How does your CZ shoot 45-52g BT bullets? My CZ Varminter shoots FB bullets up to 60g well, but shoots BT bullets best when they are under 55g.

Flat based bullets allow more of the bullet bearing surface into the lands as well as more bearing surface in the case neck which could offer more stabilization.

in my reading about long range shooting, I have seen it said that boat tails need some down range distance before they stabilize, some hundreds of yards- so perhaps the range you are shooting at is within that distance they need to settle down.

on the other hand, the BT's I use in my 17HMR are quite accurate within 200+ yards.

Probably has to do with your particular rifle and what it prefers. 1:12 is perfect/adequit for 55gr bt in 224 so twist has nothing to do with it. Not to mention if they are not stabilizing it is usually magor groupings not slightly larger groups. Just because your handloading does not guarentee ALL bullets will group.

Perry

I would have your crown touched up, most of the time when there is that much difference- there are some imperfections in the crown.


www.duanesguns.com

I have just gotten to where I prefer the non boat tailed bullets....


They have been less finicky for me over the years so I just stick with them whenever possible...

But Duane in Norda 'Kota... is probably hitting the nail on the head....he has a good reputation...so must know what he is talkin about...

cheers'
seafire