Barrel Bore Dia Question

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crb

Ray Brooks
One of the mass market bbl makers has a '22 Mag' bbl blank. I inquired and the bore dia is .219 with the grooves at .224. They do not recommend using this bbl for a centerfire cartridge like a 223. Their dedicated 22 cf bbl measures .220 x .224. The 22 mag blank has a 14 twist and their 22 cf blanks have 7 or 9.

What would be the results of using the .219 x .224 bbl for a 223 or similar cartridge ? Possible slightly higher pressures ? Anything else ?

Thanks
Ray
 
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bbl steel

It may not be the actual bore diameter that concerns them ,it may be the grade of steel and the heat treatment for the different uses??Maybe someone else can enlighten us for sure.

They are concerned with SAAMI specs though .

chris
 
I thought that a lot of rimfire barrels were made from a lower grade of steel, maybe 1150 or something close to that. Also, .002 depth of grooves seem shallow to me.
Can't you mention the manufacturer or their website?
 
Checked a Krieger .224 CF blank and it is stamped with .2180" bore and .2240" groove diameter. I agree that dimensions don't appear to be the issue.
 
I understand that some barrels, designed for the lower pressures of rimfire have, at least in the past, been made from mild steel that is softer and less strong than chromoly. I wonder what the barrel that you are considering is made of.
 
The bore and groove diameters you mention...

are perfectly suitable for a .22 centerfire caliber - .217" is a standard bore for such barrels, and .224 is, of course, the nominal standard groove diameter. 14" pitch is suitable for lighter bullets, but is not well-suited for any of the heavier bullets - say, over 50 grains.
It is more likely that the heattreatment or physicals of the particular steel used by the maker are not, in his opinion, sufficient for CF applications. Take his word for it.
mhb - Mike
 
Guys, Industry standard for most .224 centerfire caliber barrels is .219 bore x .224 groove.

Industry standard for .22RF barrels is .217 bore x .222 groove.

Industry standard for a .22RF Mag. barrel is .219 x .224.

I'm not making it up. This is out of the Saami book. If we have to make any sort of ammunition test barrels weather it is a pressure or accuracy barrel we have to make it to the Saami Spec.

Now some barrel makers even us offer different bore and groove sizes besides the standards.

When ever you reduce the surface area of the bore your pressures will go up some.

The comment about the .220 bore for a centerfire barrel is a new one and why they don't recommend a .219 when that is the industry standard? Is it a button barrel maker?

The comment on the steel being softer/milder for .22RF barrels. Not saying it isn't possible that a barrel maker/manufacturer is doing this if so probably because the steel is cheaper in cost.

All of our barrels are made out of 416R s.s. or 4140 c.m no matter what the caliber. We don't use a different or cheaper grade for a .22rf barrel.

Later, Frank
Bartlein Barrels
 
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