Who Figured This Out???

[JohnH]

If you go to this link, http://www.saami.org/specifications_and_information/index.cfm?page=CC you can see the cartridge and chamber drawings manufacturers use for dimensioning their products. These are the SAAMI standards. Look at 44 Remington Magnum in pistol and rifle and you will find a barrel dimension of .417 bore and 429 groove for pistol and .424 bore and .431 groove for rifle. I've had fits with a couple rifle barrels over the years only shooting one or two boolits and loads decently at lower velocities, and practically no success at full pressure with accuracy that was usably predictable beyond 30 yards. In a thread on another board a few months back I read of another gentleman having the same problem. Set me to thinking. I got an NOE 434421 mold this past week, cast some up lubed with 45-45-10, no sizing and eureka! my Rossi '92 shot a sub 2" group at 40 yards with the first load tried, been raining and ain't been able to get outside since, but seems like a solution is at hand.


So what is the gig? Who decided that handguns and rifles needed to have bore and groove diameters so different that not even jacketed bullets would shoot well from one to the other. My Rossi and Handi will both throw buckshot patterns with .429 diameter projectiles, the Rossi wants to calm down with .430, while the Handi continues to act like a smooth bore. I've yet to be able to try the NOE boolit in the Handi, but suspect it will make it behave too.


Perhaps the takeaway is to always slug your barrel and assume nothing, but it strikes me as completely asinine for people who make firearms and ammo everyday to not be aware of this problem and to do nothing to resolve it.

[mozeppa]

So what is the gig? Who decided that handguns and rifles needed to have bore and groove diameters so different that not even jacketed bullets would shoot well from one to the other. My Rossi and Handi will both throw buckshot patterns with .429 diameter projectiles, the Rossi wants to calm down with .430, while the Handi continues to act like a smooth bore.

i'd think part of the problem is that even though they are the same caliber ...the difference lies in the length of the barrel and how much the bullet stays under a "pressurized" condition in each bore.

but i'm only guessing.

[high standard 40]

I had a 44 Mag Handi (for a short time) and I feel your pain. My example had a .434" groove. I had several 44 molds but none that would come anywhere near that diameter. A call to the factory assured me that my barrel was "in spec" which for them was .431" plus or minus .003". :shock: Draw your own conclusion here. I quickly sold mine and moved on to greener pasture. Good luck with yours.

[runfiverun]

wait till you run into a .432 barrel with the rifling twist rate cut slow for a 44-40, and it will only shoot 200 gr boolits...
then once you figure that out, you realize it's got metford type rifling too, so it needs a bigger and harder boolit...
and to make matters worse it ain't even your rifle nor can you see it in person.
and they wanna hunt deer with it...

[parson48]

I had a Marlin 44 mag several years back that slugged at around .433 (don't remember exact size). If I could cast a fat enough boolit it would shoot OK. I bought one of Ranch Dog's 265 gr. molds- lapped it a little, beagled it, and came up with a workable projectile for it. I did talk with a tech at Marlin, he said that it was "within specs".

[leadman]

I looked at the SAAMI drawing for the 44 magnum and it shows a .432" lead bullet with the bore and groove dimensions the OP stated. Been this way as long as I can remember.
Love it when people complain about oversized throats in revolver chambers when the SAAMI spec is .432".
If you look at the drawing for the 41 mag it shows a .410" jacketed bullet and a .411" lead bullet.
The companies making the guns and accessories like molds tend to ignore the SAAMI standards in these areas.
Had a guy at Redding arguing with me about the size of the proper lead bullet per SAAMI for the 41 mag. My Ruger SBH Hunter in 41 mag has .411" throats. I asked if Redding was a member of SAAMI and he blubbered some. I informed him the anyone can access the SAAMI website and he should do it.

[mdi]

Well, for me at least; no problem. In my opinion if one wants to shoot lead bullets in their gun, one should know the important dimensions of their guns. In other words, shoot the right size bullet fer yer particular gun! I have slugged the barrels of all my guns. I have slugged/measured all the cylinder throats of my revolvers. I have determined the throat dimensions for my 45 ACPs. And I also think a micrometer is a necessary tool for a lead bullet shooter.

I have one of those "bad" barrels on my Puma (.432+") but it took only 17.75 seconds to decide on a bullet for accurate non-leading shooting once I knew the groove diameter. I modified a Lee size die and get accurate shooting cast lead bullets (as far as my old eyes can shoot). Without knowing these facts/dimensions, it's all a WAG...