I should have used a different word than original. I meant the powder used by the Italians in WW2 when my carbine was made.
Carcano shooting
- Thread starter Claven2
- Start date
I should have used a different word than original. I meant the powder used by the Italians in WW2 when my carbine was made.
I reload for my carcano using 145gr powder coated cast bullets sized to .268 with 11.0gr of trail boss powder or 8.0gr of Red dot. nIt shoot at about 1300fps and, I get 4'' groups at 100m.
It's a light load but more than enough to punch paper.
It's a light load but more than enough to punch paper.
I don't know. It think it's gain twist, but hard to tell with the naked eye. M41's and some m91/38's had regular rifling.
Be interesting, obviously to go from 19" to 8" in a 17.7" barrel it would have to be "more" progressive than in a 30" barrel. Or did they cut off one end or the other of a full length barrel?
Or is it basically like a rifled choke tube, a short section of the "proper" twist at the end?
So many questions.
Ok so here's what I found. From the chamber, a tight jag on a rod will rotate one full turn in 11 inches of travel. If I repeat the same test from the muzzle, it's 1 turn in 10 inches.
So it's gefinitely gain twist, but it's not a dramatic change in twist over the bore length. The whole barrel, including chamber, is only 17.5 inches, so just under 14.75 inches of rifling total.
So it's gefinitely gain twist, but it's not a dramatic change in twist over the bore length. The whole barrel, including chamber, is only 17.5 inches, so just under 14.75 inches of rifling total.
I think by the time the bullet leaves the bore it's likely around 1:9. Remember, it's progressive rifling, so 1:10 measured at the muzzle over a foot with a rod is more like a twist that starts around 1:12 at the camber and ends 1:9 at the muzzle, possibly a little faster. Could even be 1:8, very hard to measure using the primitive method is was using.
I've tried just that with .264 jacketed powder coated to .267 for my carcano and a Swedish Mauser. Also tried .312 bullet powder coat to .315 for an enfield. It didn't worked. I don't understand why! It shot as the non powder coated bullet.
The appropriate sized cast bullet shoot nice in any rifle I have, as long It as sufficient rifling left.
Cast bullet is THE answer to to the non standard orworn bore.
Since JetBullets closed up, if anyone who is casting (and ideally powdercoating) .268 bullets is looking to sell some, let me know. I am down to my last ~200 or so JetBullets and now that I have 2 Carcano's I think I'll chew through those fairly quickly
To me it looks like the original load was a max charge of what would today be a slow shotgun powder with a cotton wad under an open base 162 gr bullet. IMO the gain twist was an attempt to keep pressures down, I wouldn't be surprised if they have a generous free bore as well.
First I'm going to try factory, maybe they know something. Then the Lapua 100 grainer and I've got 6.5 bullets of 129, 140 and 160 grains on hand.
First I'm going to try factory, maybe they know something. Then the Lapua 100 grainer and I've got 6.5 bullets of 129, 140 and 160 grains on hand.
Many who reload the Carcano use the Hornady "0.268"" bullet (in fact it measures 0.267"), and are aware of the strange loading requirements prescribed by Hornady for their use, e.g. magnum primers and specific powders and charges. What you see below is what member "mag" from Gunboards had to say about it in 2008.
It appears that using 0.264" bullets (any other bullet but the Hornady 0.268"), while not necessarily accurate, is safe, and requires no special loading restrictions. The same would go for cast bullets, except that they could be sized appropriately, and would be accurate (at least they are for me).
That said, it contains some good info and the opinion on the Hornady 0.268" is mostly moot anyways as few are used anymore.
It appears that using 0.264" bullets (any other bullet but the Hornady 0.268"), while not necessarily accurate, is safe, and requires no special loading restrictions. The same would go for cast bullets, except that they could be sized appropriately, and would be accurate (at least they are for me).
06-20-2008, 08:51 PM
mag
Senior Member
A friend and I have shot 1000's of the "big" Hornady .267 dia 160 rn bullets, A lot of testing in over 50 different carcano rifles and carbines of all models. We did this as soon as the bullets came out. Both of us have found that there is a problem with this bullet . Here is what we have found, and why it is a problem. We did find that sometimes you could get 30 or 40 rounds fired with no problem before something bad happened. Since we were firing over 100 rounds per day at times, it was much more likely for us to see it compared to a guy that only fires 20 rounds every month or so. The designer of the bullet did not seem to understand some things about the way most European military bores [ and Carcanos ]were made to shoot. They did not use groove size bullets for a reason . The Carcano has very deep rifling and this is the cause of some of the problem. Also the Carcano's bore size [ land and groove ] did change over the years. The early rifles had a larger groove [ about .272 ] and the groove size did get smaller to about .266 [ with shallower rifling ]with the M-41's . So any pressure data produced from one size bore with not be the same as what was made from another.
The land size is what is causing the Hornady bullet to have problems. We have found that the rifles with the smaller lands are more likely to have problems with the bullet, and that it can be a size difference as small as .001 [ .002 total of both sides ] . The deep rifling of the Carcano was cutting through the jacket on the original "big" bullet. To fix this the jacket was made thicker , this caused another problem, that was made worse by the gain twist rifling. It was very hard for the rifling to engrave the thick jacket so deep into the bullet [ this slows the bullet down and causes pressures to go up. Then when the bullet has to "re-engrave" when the twist changes the pressure goes up some more. The " recommended" powders did help with this on some of the less tight bore [ their test rifles ? ] , but it still did not fix the problem on real tight bores [ that they did not have to test ? , but other's could be shooting ] .
There was a reason the Italians made their bullets .265 to .266 and used the material that they did for the bullet jacket . The long undersized bullet [open at the base] would still ride straight down the bore, the base would seal, and the "extra" bullet material that was displaced by the deep rifling would have the extra groove depth to go into,, and there was also room for the rifling cut "wings" to shift to as the twist changed . To see why this is a problem all you have to do is figure the bore area of a .253 land - .268 groove barrel and compare it to the area of a .267 dia bullet. Where is all that extra displaced bullet material going to go ? It is not going to displace exactly the same each shot. That is why pressures can spike .
I have seen the big bullet [shot with the recommended load] have the jacket get stuck in the bore ,way into the gain twist, as the lead core exited. This could also be another cause of over pressure if a shooter fired another round into the stuck jacket. Between the two of us we have had many case failures with this bullet. We will not use it in Carcanos any more. So the bottom line is they made a bullet that will only work in some of the rifles, needs the load to be matched to each rifle, is not for non-expert reloaders [ or "custom reloaders" that have no idea what size bore rifle their ammo will be used in ] and has a very narrow reloading spec . I knew the bullet would be pulled from the market after a while from the problems I knew it was going to cause. So I bought several 1000 extra right after we did our testing. The bullet does work well and shoot well in some OTHER types of " 6.5mm " rifles, many times it is the only one that will . This is what I have found, some may find it interesting . I do feel the big bullet will get you [in many of the rifles] if you shoot it enough. I had a M-91 lr that was shooting it pretty well, over 80 rounds in testing with no problems at all and good accuracy . I shot the rifle in a match and the 14 shot blew the case apart. So number 94 shot in THAT rifle got me. mag
I take what he says with a grain of salt. It sounds good with a claim that he and a friend shot 1000's of this bullet (and he later states in a couple of dozen different guns), lots of theory, but no pics, no other person to corroborate what he says. "mag" does not take kindly to people questioning him, and will strongly defend what he said, so it's pointless to ask for that. mag
Senior Member
A friend and I have shot 1000's of the "big" Hornady .267 dia 160 rn bullets, A lot of testing in over 50 different carcano rifles and carbines of all models. We did this as soon as the bullets came out. Both of us have found that there is a problem with this bullet . Here is what we have found, and why it is a problem. We did find that sometimes you could get 30 or 40 rounds fired with no problem before something bad happened. Since we were firing over 100 rounds per day at times, it was much more likely for us to see it compared to a guy that only fires 20 rounds every month or so. The designer of the bullet did not seem to understand some things about the way most European military bores [ and Carcanos ]were made to shoot. They did not use groove size bullets for a reason . The Carcano has very deep rifling and this is the cause of some of the problem. Also the Carcano's bore size [ land and groove ] did change over the years. The early rifles had a larger groove [ about .272 ] and the groove size did get smaller to about .266 [ with shallower rifling ]with the M-41's . So any pressure data produced from one size bore with not be the same as what was made from another.
The land size is what is causing the Hornady bullet to have problems. We have found that the rifles with the smaller lands are more likely to have problems with the bullet, and that it can be a size difference as small as .001 [ .002 total of both sides ] . The deep rifling of the Carcano was cutting through the jacket on the original "big" bullet. To fix this the jacket was made thicker , this caused another problem, that was made worse by the gain twist rifling. It was very hard for the rifling to engrave the thick jacket so deep into the bullet [ this slows the bullet down and causes pressures to go up. Then when the bullet has to "re-engrave" when the twist changes the pressure goes up some more. The " recommended" powders did help with this on some of the less tight bore [ their test rifles ? ] , but it still did not fix the problem on real tight bores [ that they did not have to test ? , but other's could be shooting ] .
There was a reason the Italians made their bullets .265 to .266 and used the material that they did for the bullet jacket . The long undersized bullet [open at the base] would still ride straight down the bore, the base would seal, and the "extra" bullet material that was displaced by the deep rifling would have the extra groove depth to go into,, and there was also room for the rifling cut "wings" to shift to as the twist changed . To see why this is a problem all you have to do is figure the bore area of a .253 land - .268 groove barrel and compare it to the area of a .267 dia bullet. Where is all that extra displaced bullet material going to go ? It is not going to displace exactly the same each shot. That is why pressures can spike .
I have seen the big bullet [shot with the recommended load] have the jacket get stuck in the bore ,way into the gain twist, as the lead core exited. This could also be another cause of over pressure if a shooter fired another round into the stuck jacket. Between the two of us we have had many case failures with this bullet. We will not use it in Carcanos any more. So the bottom line is they made a bullet that will only work in some of the rifles, needs the load to be matched to each rifle, is not for non-expert reloaders [ or "custom reloaders" that have no idea what size bore rifle their ammo will be used in ] and has a very narrow reloading spec . I knew the bullet would be pulled from the market after a while from the problems I knew it was going to cause. So I bought several 1000 extra right after we did our testing. The bullet does work well and shoot well in some OTHER types of " 6.5mm " rifles, many times it is the only one that will . This is what I have found, some may find it interesting . I do feel the big bullet will get you [in many of the rifles] if you shoot it enough. I had a M-91 lr that was shooting it pretty well, over 80 rounds in testing with no problems at all and good accuracy . I shot the rifle in a match and the 14 shot blew the case apart. So number 94 shot in THAT rifle got me. mag
That said, it contains some good info and the opinion on the Hornady 0.268" is mostly moot anyways as few are used anymore.
Last edited:
Andy do you have a higher res version of the second plate? I can't make out any measurements.
The s-7186b plate shows theilitary bullet at
264" with a rebated base (which should flare some).
The older older 7186 dwg shows a solid base. With dimensions I can't make out.
The ww2 military rounds I had mic'd .266-.267 according to my notes, but I no longer have any examples to measure here - they got fired in a test a few years back.
Anyone got original rounds they can measure right ahead of the neck crimp?
The s-7186b plate shows theilitary bullet at
264" with a rebated base (which should flare some).
The older older 7186 dwg shows a solid base. With dimensions I can't make out.
The ww2 military rounds I had mic'd .266-.267 according to my notes, but I no longer have any examples to measure here - they got fired in a test a few years back.
Anyone got original rounds they can measure right ahead of the neck crimp?
Last edited:
