This afternoon, I took out my Carcano carbine for the first time. Should have done it months ago buttttttt
I tried three different bullets, using 32.0 grns of IMR4320 over CCI250 primers. Temp was around 22C
The bullets I used:
160 grain Swede surplus, .264 diameter, cupro nickel full metal jacket with exposed lead base - 3/4 inch 3 shot group at 50 yards high of course
160 grain Hornady .268 diameter, copper jacket soft point with enclosed base -1 inch 3 shot group at 50 yards a bit lower than the fmj.
140 grain Swede surplus, .264 diameter copper full metal jacket with exposed lead base - 3 shot group at 50 yards +1 inch a bit lower than the heavier bullets??????
This rifle has a perfect median spec bore. It was like winning a lottery. It's in NRA VG condition inside and out.
groove diameter is .268 and land diameter is .257
IMHO, the reason this rifle shoots both bullet diameters and weights so well is the median bore diameters shooting "exposed lead base bullets"
Exposed lead base bullets are almost impossible to find these days, so I'm not encouraging anyone to try to find them at their local gunshop or big box supplier.
Back in the day, before CNC equipment became available bore diameters of both military and commercial rifles varied several thousandths of an inch from one bore to the next. The bullets were often slightly over or undersized as well.
They're accuracy parameters were generous to say the least, when compared to the excellent consistency of todays components.
The folks designing the equipment back then mostly had a very good understanding of how to make ''cast'' bullets shoot well, under similar conditions.
They were tasked with making "jacketed'' bullets shoot at least as well and hopefully better.
Their solution was IMHO ingenious. They made a cup of the metal jacket, filled it with a lead core and swaged them together, with the lead base purposely exposed.
Somewhere along the way, one of their engineers, metalurgists? figured out that when the new "high pressure" powders burned, they would creat enough pressure to force the lead to expand inside the metal jacket and obturate into the grooves of the rifling.
It worked quite well then and still does today.
I was hoping that Campro was going to offer exposed lead base bullets for the 303 British, but I don't see it happening anytime soon.
I still have some .312 diameter exposed lead base bullets but they won't last for as long as I hope to be shooting.
I tried three different bullets, using 32.0 grns of IMR4320 over CCI250 primers. Temp was around 22C
The bullets I used:
160 grain Swede surplus, .264 diameter, cupro nickel full metal jacket with exposed lead base - 3/4 inch 3 shot group at 50 yards high of course
160 grain Hornady .268 diameter, copper jacket soft point with enclosed base -1 inch 3 shot group at 50 yards a bit lower than the fmj.
140 grain Swede surplus, .264 diameter copper full metal jacket with exposed lead base - 3 shot group at 50 yards +1 inch a bit lower than the heavier bullets??????
This rifle has a perfect median spec bore. It was like winning a lottery. It's in NRA VG condition inside and out.
groove diameter is .268 and land diameter is .257
IMHO, the reason this rifle shoots both bullet diameters and weights so well is the median bore diameters shooting "exposed lead base bullets"
Exposed lead base bullets are almost impossible to find these days, so I'm not encouraging anyone to try to find them at their local gunshop or big box supplier.
Back in the day, before CNC equipment became available bore diameters of both military and commercial rifles varied several thousandths of an inch from one bore to the next. The bullets were often slightly over or undersized as well.
They're accuracy parameters were generous to say the least, when compared to the excellent consistency of todays components.
The folks designing the equipment back then mostly had a very good understanding of how to make ''cast'' bullets shoot well, under similar conditions.
They were tasked with making "jacketed'' bullets shoot at least as well and hopefully better.
Their solution was IMHO ingenious. They made a cup of the metal jacket, filled it with a lead core and swaged them together, with the lead base purposely exposed.
Somewhere along the way, one of their engineers, metalurgists? figured out that when the new "high pressure" powders burned, they would creat enough pressure to force the lead to expand inside the metal jacket and obturate into the grooves of the rifling.
It worked quite well then and still does today.
I was hoping that Campro was going to offer exposed lead base bullets for the 303 British, but I don't see it happening anytime soon.
I still have some .312 diameter exposed lead base bullets but they won't last for as long as I hope to be shooting.
