Jacked shoots well but lead tumbles?

Guys first I would like to thank you for all your help. Just when you think you figured it out another question pops up.
I am shooting an 1893 Carcano with gain twist rifling. When I shoot the original bullets from pulled cases it shoots very well, and is accurate. When I shoot 160 gr lee bullets size to .268 the bullets strike sideways at 25 yards. I am using 5744 with velocity around 2000fps, as per the loading data. The groove diameter is .267-.268. The bullets are seated to touch the rifling and are lubed with liquid ALOX. Should I size larger(modify the mold) or use a lighter bullet?
Thanks NS

First try slowing it down a little bit, try say 8-10gr Unique for around 1400-1500FPS. You might be pushing the boolit and alloy past it's RPM gain twist threshold. Be aware that your case neck could be re-sizing your booits down when seating, too. If that's the Lee 6.5 "cruise missile", it's known for it's tippy attitude but, should give serviceable accuracy. I get the 6.5 "cruise missile" mold to drop at .270 by adding 2% tin to COWW's and running the mold hot for frosted looking boolits. A lighter (shorter) boolit will probably be better, though. I think NOE has a 134gr Loverin design bullet mold and a 149gr group buy going on. NOE also has a 145gr and 163gr bore riding boolit mold. Check to see what fits best.

Try 'em bigger, slower, and softer.

so which twist do you go with to follow the rpm thingy the one you start with for the engraving which is the problem or the one you end up with which affects the external.
this is a poor launch versus velocity problem. 5744 sucks for your velocity.

slow it down or search out a better launch/fit with a different powder and boolit design.

Great advice listen to the experts. 2000fps is the goal after much trial and error. Shoot for 15 to 1600 fps as a start and move up. You are on the right track just trying to skip a few steps. Back up and give it another go. Is your boolit gas checked? If not slow it down to under 1400fps or slap on a gas check.

I started with 10 gr. of unique then went to the 5477 starting load of 15.6 gr 1552 fps(as per load data), then I went to 20.0 gr at around 1900 fps. all went side ways. I am getting a .268 sizer so I will be able to add gas checks. The mold is the Lee cruise missile. Should I try to leement the mold or polish it larger? Next I will try a Lyman mold of 140 gr.. The alloy was hard a #2 alloy.

Most of the Lyman molds will not drop at .268", they run .266". The only Lyman mold I have that will is a 266645.

A gas check is needed for more than about 1400-1500 FPS.

Your boolit should be sized to your rifles free bore area between the case mouth and throat.

See if this pertains to your firearm.
http://educationforum.ipbhost.com/index.php?showtopic=20247

Some interesting portions:

all 6.5 Carcanos up until 1938 had riflings that began at a gentle 1:19 at the chamber and gradually tightened to a 1:8 twist at the muzzle

. No sooner had the M1891 been introduced than it was decided to be produced in a cavalry carbine in 1893 called the M1893 Cavalry Carbine. Its barrel was just over 17" in length. Remember the progressive twist rifling of the M1891? These carbines were produced by shortening M1891 long rifle barrels and, of course, the part of the barrel with the tightest riflings (the muzzle) was cut off; leaving the carbine barrel with a maximum rifling of possibly 1:13 which was totally inadequate. Try to imagine what the resulting lack of spin would do to the performance and stability of the 6.5 mm bullet in flight.

If the above pertains to your gun you need the shorter boolit.

Always use a gas check if the boolit is designed for it. It simply adds an unknown when you don't, and that prevents you from finding out what is actually going on.

Shoot it at the various loads with the gas check, sized to fit your throat if possible, .002" over groove size if you can't. If you can't get that boolit that big you need to change boolits.

you need a pound slug of your throat to determine what you need,,, weight is irrelevant.
Fitment both mechanical and static is what is needed.
twist means almost nothing once that is done properly...

It might be the boolit.
Lyman Cast Bullet #3 shows for the 6.5 Carcano (all testing was in Italian service carbine with gain twist rifling) the following three boolits:
119 grain #266324
129 grain #266455
143 grain #266469

Most were loaded to velocities between 1300 and 1600 fps. Only two loads were shown just slightly over 2000 fps , they were maximum loads with 2400 powder.

Try the 8 to 10 grains Unique load, or an equivalent load, trying for between 1300 and 1700.
If that doesn't work, might be time to look for another mould.

Gary

Quote:

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Originally Posted by MT Chambers

Try 'em bigger, slower, and softer.

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Lots of good suggestions. I like this one. :) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Motor

All good advice..just wondering, have you cleaned all the copper fouling out of bore?

I have cleaned it. it loves the original military bullets 160 gr and likes 130 grain lead but not the 160's.