carcano & cruise missile

[StarMetal]

I used Dacron here, out of my guest room pillow.

The vertical stringing was with the A2400. About 1" wide and 6" high.

Up to now I've attributed it to projectile instability. With the oven hardened CM's the bullets fly straight, the group width tightened, and the vertical skew shows up more clearly.

The H4831-SC - even without filler - did not exhibit stringing. (And I was relaxed on measuring this powder compared to the A2400, where I trickled.)

I don't have much experience with 4831 but the other stick powders I use seem to work well with light loads, especially H4895.

Is there a reason you have to use the CM? I can understand the velocity range you are wanting, but why not use a lighter shorter bullet?

[Boz330]

Is there a reason you have to use the CM? I can understand the velocity range you are wanting, but why not use a lighter shorter bullet?

Not sure about bkbville but it is the only thing with enough diameter for the Carcano. The current lot casts at .272. Mine is .269. The NEI boolits that I have from a mold I sold some time back are only .266.
I'm thinking of cutting my CM mold down and see how it does. It is pretty cheap so no loss if it doesn't work.

Bob

[StarMetal]

Not sure about bkbville but it is the only thing with enough diameter for the Carcano. The current lot casts at .272. Mine is .269. The NEI boolits that I have from a mold I sold some time back are only .266.
I'm thinking of cutting my CM mold down and see how it does. It is pretty cheap so no loss if it doesn't work.

Bob

Would .268 work for you Bob?

[bkbville]

Joe,

I went with the CM to fill the bore (its droping .270) (like Boz330)

I thought the 170 gr would be a little better to move this out to 500 yds.

I could not find a kurz mould, though it would have been my first choice - 145gr if I recall.

I didn't think I could beagle a lyman 226469 enough.

Back a page or so I hack-sawed a dozen CM's to 140 gr. These shot well.

I can't bring myself to shorten the mould - it seems like it would be difficult to cut straight.

Also, I hope to pick up a swede at some point. Then again, at .270 this is fat for a swede.

What's the deal with the CM? Older posts brag about it, newer posts are all keyhole...

[Boz330]

Joe, I just reread my post and it sounds like my mold is .269 but the barrel on my Carcano is .2685 to .269. The mold is .272 and I don't size them at all. To answer your question, I don't know if they would work. I would think that there might be some leading. The grooves on the Carcanos are pretty deep compared to other milsurps.

Bob

[StarMetal]

BaBores remake of the Kurtz drops a little over .268 with 50/50 alloy. That and the original Kurtz is what I'm shooting in the Swede and as you know the Swede has as deep or deeper rifling grooves then the Carcano and to boot a fast twist...although I'm not positive what the fast part of the Carcanos gain twist is. What I'm getting at is I've shot bullets not big enough in the Swede (then finally getting the right sizer and bullets) with no leading and I'm pushing them as your probably know. Most are just AC which is not a real hard bullet, some are water dropped.

If you have a bullet that just barely makes groove size, or slightly under, with the right powder, the right loading, if you whack it hard enough it will bump up and work. I know lot of things have to be right there, but it does work.

It certainly wouldn't hurt to try some of BaBores Kurtz and he remake of the 469 Lyman too.

[bkbville]

Sounds like a good idea but I don't see the kurtz on BaBores cast pics site - actually nothing in 6.5 - ??any idea on this??

IIRC the gain twist on the Carcano M91 Fucile barrel (and the vetterli barrel liners) starts 1:19 down to 1:8. (which Greenhill-wise works for a 170gr)

I can't push the Vetterli action too fast - it started out as a BP design. I even get concerned over 17gr of A2400.

I think what the hardening did was to prevent the gain twist from mushing the engraving.

My theory being by the time the (softer) boolit got to the 1:8 end of the barrel it was riding the lands, the rifling imparting no further spin; hence never achiving a stable rotational velocity. I haven't been able to do any bullet recovery to verify this.

[Boz330]

Sounds like a good idea but I don't see the kurtz on BaBores cast pics site - actually nothing in 6.5 - ??any idea on this??

IIRC the gain twist on the Carcano M91 Fucile barrel (and the vetterli barrel liners) starts 1:19 down to 1:8. (which Greenhill-wise works for a 170gr)

I can't push the Vetterli action too fast - it started out as a BP design. I even get concerned over 17gr of A2400.

I think what the hardening did was to prevent the gain twist from mushing the engraving.

My theory being by the time the (softer) boolit got to the 1:8 end of the barrel it was riding the lands, the rifling imparting no further spin; hence never achiving a stable rotational velocity. I haven't been able to do any bullet recovery to verify this.

I never thought of that. With the length of the driving section on the CM the gain twist could be stripping by the time it gets to the fast twist portion where as in the Swede the twist is constant all of the way. By going to a shorter driving section the change in twist rate is not quite as detrimental to the engagement.
I tried a 129gr boolit in my Swede years ago and it shot quite well, but it is a hunting rifle so I shoot jacketed in it. Actually I don't shoot it much anymore but it is a great rifle to break in young shooters to a high powered rifle and deer hunting. All of my deer hunting is done with a BPCR now. I just enjoy the challenge of doing it the old way, I guess because I'm old now.
bkbville if I get mine cut down anytime soon I'll send you a few to try. I have a milling machine here at the shop so it shouldn't be a big deal and the mold isn't that expensive.

Bob

[StarMetal]

Sounds like a good idea but I don't see the kurtz on BaBores cast pics site - actually nothing in 6.5 - ??any idea on this??

IIRC the gain twist on the Carcano M91 Fucile barrel (and the vetterli barrel liners) starts 1:19 down to 1:8. (which Greenhill-wise works for a 170gr)

I can't push the Vetterli action too fast - it started out as a BP design. I even get concerned over 17gr of A2400.

I think what the hardening did was to prevent the gain twist from mushing the engraving.

My theory being by the time the (softer) boolit got to the 1:8 end of the barrel it was riding the lands, the rifling imparting no further spin; hence never achiving a stable rotational velocity. I haven't been able to do any bullet recovery to verify this.

Send Babore a pm as he has both the remakes of group buy 6.5 Kurtz and the Lyman 266469. I have one of each.

[bkbville]

I never thought of that. With the length of the driving section on the CM the gain twist could be stripping by the time it gets to the fast twist portion where as in the Swede the twist is constant all of the way. By going to a shorter driving section the change in twist rate is not quite as detrimental to the engagement.

The shorter the bullet, the slower the turn required to stabalize - it's more the length of the bullet than the weight, IIRC the greenhill formula. So even if the shorter soft CM is being forced past the 1:8, it can still be stable.

Well, that's the theory...

[Boz330]

The shorter the bullet, the slower the turn required to stabalize - it's more the length of the bullet than the weight, IIRC the greenhill formula. So even if the shorter soft CM is being forced past the 1:8, it can still be stable.

Well, that's the theory...

I agree but why is the boolit not reaching the proper spin velocity for the length. That boolit should stabilize with the twist rate at the exit but it's not. A shorter engagement area and more bore riding section might have a better chance of getting the boolit up to the proper rotational velocity with out stripping. Maybe I'm wrong about this but it seems to make sense in my mind. By shortening the CM mold from the back you are working on both problems at the same time.
For me the Carcano is a fun project not a must do thing. I have as much in the reloading stuff as I paid for the rifle probably a little more. Somehow I just can't turn down a $60 rifle. And if all else fails I can unfold the bayonet and gig frogs with it.

Bob

[barnetmill]

How well does the rifle shoot with commercial ammo?
Many military rifles get damage about the end of the muzzle from cleaning. I would not think it would cause tumbling, more like inaccuracy. Another possibility is a bulge or ring in the barrel that might cause tumbling. Did you test this gun with a shorter bullet to prove that the barrel is good? Long thread so I did not read every post. You can detect a ring in the barrel with a tight patch on a cleaning rod. The barrel may also be badly corroded at the throat.

[bkbville]

Boz,

I'm saying that somewhere on the transition from 1:19 down to 1:8 the change in angle of the engraving (regardless of the length of engagement area) isn't tracked by a soft boolit - the engraving gets smoothed over.

A 1.26" CM wouldn't stabalize until it runs at least 1:8.5 twist.

When the alloy is soft and the pressure sufficient the engraving is gone before it reaches the final 1:8 section. It has no further grip on the changing gain. It's running at twist rate where it lost traction. It's not rotating fast enough to stabalize flight.

I lower the velocity of the longer "soft" CM to 1300fps and there isn't sufficient force to mush the engraving, so the long bullet tracks and runs the 1:8 terminal twist of the carcano. It's rotating fast enough and flight stabalizes.

A shorter 1.0" CM needs to run only 1:11 twist to stabalize.

The "soft" shorter CM doesn't need to run the 1:8 twist to stabalize. Even at the same 1650fps pressure it is already stable when it's engraving is mushed. Even if its riding lands with no grip it's already rotating fast enough to stabalize flight.

I harden the full length CM boolit and raise the pressure and velocity back to 1650fps. The harder boolit tracks the rifling and doesn't get mushed, keeps it's engraving, and runs the 1:8 twist. It rotates fast enough to stabalize in flight.

Of course, I could be completely wrong. But this is my attempt to make sense of the data and observations I have.

Boolit recovery would help here.


Barnetmill,

I've shot 140 gr "cut" cruise missles and Prvi 139gr FMJs. Both were stable.

The Prvi's were .264 as well - under groove size, but still grouped well.

The throat/barrel/crown are in good shape.

[Boz330]

We are thinking in the same vein. My boolits were ACWWs and the best groups were at slower velocity's. Just over 2MOA with 3MOA sights but they are fishtailing going through the target.
I have some Lino type or could water drop to see if that makes a difference after all it is the chase that's fun.
The barrel on my Carcano looks damn near new. It was late war production and appears to be a bring home although I don't know that for sure. Probably been in a closet for 50 years.

Bob

[Boz330]

Well tried a WW linotype mix yesterday in the Carcano to see if the harder boolit would take the rifling without stripping. These were hard enough that you could mark them with your finger nail but not actually scratch them. Didn't work either, not even a good shotgun pattern.
Next try will be cutting the mold down to see if a shorter boolit is the answer. After that the whole kit & caboodle goes up for sale.
Had another problem yesterday as well, the firing pin was striking weakly and I was getting failure to fire. When I checked protrusion it seemed sufficient. Anybody know how the bolt comes apart so I can clean it or maybe replace the spring.

Bob

[swheeler]

Well tried a WW linotype mix yesterday in the Carcano to see if the harder boolit would take the rifling without stripping. These were hard enough that you could mark them with your finger nail but not actually scratch them. Didn't work either, not even a good shotgun pattern.
Next try will be cutting the mold down to see if a shorter boolit is the answer. After that the whole kit & caboodle goes up for sale.
Had another problem yesterday as well, the firing pin was striking weakly and I was getting failure to fire. When I checked protrusion it seemed sufficient. Anybody know how the bolt comes apart so I can clean it or maybe replace the spring.

Bob

http://www.surplusrifle.com/carcano9...bly/index.asp- Bob go here, step by step with pictures.

[bkbville]

Boz,

Here are carcano bolt disassembly instructions:

M91/38:
http://www.surplusrifle.com/carcano9...mbly/index.asp

M91/41
http://www.surplusrifle.com/carcano9...mbly/index.asp

You mention yours was a late war production; is it progressive gain? I didn't think any past '41 or so were progressive gain.

Have you slugged it? (or tried factory in yours?)

This reminds me - I was talking to a guy at the range; a few years ago he had been shooting a carcano with poor results. He finally discovered it was 7.35; he was firing 6.5 ammo. (At least it wasn't the other way around.)

I tried to recover some boolits last week to see if I could figure out what gives with the keyholing.

I had 3 thick wet phone books; I thought at 1600fps three would be sufficient (about 8".) It wasn't. They passed right through and lodged deeply in the 4x4 target stand behind them.

I'm on the look out for a few more phone books.

[Boz330]

Boz,

Here are carcano bolt disassembly instructions:

M91/38:
http://www.surplusrifle.com/carcano9...mbly/index.asp

M91/41
http://www.surplusrifle.com/carcano9...mbly/index.asp

You mention yours was a late war production; is it progressive gain? I didn't think any past '41 or so were progressive gain.

Have you slugged it? (or tried factory in yours?)

This reminds me - I was talking to a guy at the range; a few years ago he had been shooting a carcano with poor results. He finally discovered it was 7.35; he was firing 6.5 ammo. (At least it wasn't the other way around.)

I tried to recover some boolits last week to see if I could figure out what gives with the keyholing.

I had 3 thick wet phone books; I thought at 1600fps three would be sufficient (about 8".) It wasn't. They passed right through and lodged deeply in the 4x4 target stand behind them.

I'm on the look out for a few more phone books.

Thanks for the links.
It is definitely a 6.5 and gain twist. You can really tell the difference in the twist looking from the different ends. It slugs at .269 and the lino mix boolits are .273, a little bigger than the WWs. I was hoping to find a boolit in the berm but no luck. I still think that the long driving area is stripping and cutting the boolit length will help. It sure can't hurt.
No I haven't tried any jacketed and don't really want to. I have lots of different 6.5 bullets in stock, all .264. One of my first HP rifles was a Vanguard in 264 Mag and also a Swede so I'm stocked well. In fact I probably have more 6.5 jacketed than anything else.

Bob