So you think reloading is easy just open the book

[Mark W.]

So I'm loading some 30 carbine for my Ruger Blackhawk

and I decide to check a couple manuals

And here's what I find. Using 110gr bullet soft point round nose or FMJ

Pistol loads 7.5" barrel in Sierra book 10" barrel in Hornady book

Sierra #14 c2007 Alliant 2400 min charge 11.7gr = 1385fps Max charge 12.7gr = 1476fps

Hornady #8 c2010 Alliant 2400 min charge 8.9gr = 1300fps. Max charge 13.0gr = 1700fps

Now compare to the carbine loads 18" barrel

Sierra #14 c2007 Alliant 2400 min charge 10.0gr = 1469fps Max charge 12.0gr = 1745fps

Hornady #8 c2010 Alliant 2400 min charge 10.9gr = 1700fps Max charge 12.2 gr= 1900fps

Now since the only factory loads available for any handgun in .30 carbine are in fact carbine loads, it must mean that the handguns are built to handle factory carbine loads. And knowing the pressure is relieved sooner in a short barrel then a long barrel. If the handgun can handle the carbine loads you can reload to carbine pressures and not be at risk.

So why do the reloading manuals so greatly under rate the amount of powder that can be used?
And why does one manual show such a lower allowable Max for the same powder and ball?

Military loads for the .30 carbine cartridge are 15grs of H110 or Win 296 resulting in 1990fps

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[Certaindeaf]

Eyebrow hairs.

 

[bockja]

Commercial loads are safe to load in your pistol, however they are designed for use in a firearm with a longer barrel. Thus they typically use a slower burning power optimized for those guns. Using them in your revolver will result in lower velocities and a significant amount of un-burned powder. I ran QuickLOAD and with 15gr of H110, it shows you only burn about 80% of the powder in your revolver (assuming a 7.5 in barrel). I then checked the Alliant 2400, 13 gr appears about max for this powder (regardless of barrel length). I also calc a 93% powder burn rate in a 7.5 in barrel. Makes me suspect of the 14.9 gr loading for the 18 in barrel which is showing a maximum pressure of 54000 to 58000 psi depending on seating depth. SAAMI pressure for this cartridge is 40000 psi.

If you have it, something just slightly faster might perform a little better. Something along the lines of blue dot. A starting load of 9 gr with a max load of 11 gr will give you about 1600 fps out of a 7.5 in barrel (1750 out of 10 in) and 96% powder burned.

 

[Dunerunner]

Liability. Remember these manuals are instructing you on how to create an explosive device to propel a projectile from the muzzle of a firearm. they will error on the light side of the load to avoid any possibility of lawsuit. For me, I'd rather have it that way than the opposite.

 

[rick benjamin]

Pistol chambers, Revolver cylinders are not rifle chambers.
The gun must be designed to withstand the expanding pressures at every moment of the process until the bullet exits the muzzle.
Example: 38 special won't survive 38+P or 357mag loads even though the powder will fit in the 38spl case.
Was part of my learning curve. My revolver still looks brand new, but is unservicable, unrepairable because the frame stretched.

Powder burn rate.
M1 Garand 30.06 24in barrel shoots with minimum flame at muzzle
M1 Garand Tanker 30.06 18in barrel shoots a flame 2 feet long and a muzzle blast that rocks the house.
AR-15 20 inch barrel has minimal flame, and is only a bit louder than a .22,
AR-M4 14 inch barrel has a long flame, and an unpleasant muzzle blast.

Reloading can tame the beast, using faster burning powder and reduced load.
Check your fired brass for evidence of excessive pressures.
Purchase and use a <broken link removed>

Dad's Win 70 .270 (1954)
My uncle reloaded for that gun.
Dad shot those reloads exclusively. Hard hitting, long range.
Not too long ago Dad noticed a change in impact.
Took gun to his gunsmith who found the muzzle was "choked".
Suggested hot loads "pulled, stretched, migrated" barrel material to the muzzle.
Fixed it by cutting off 2 inches at the muzzle.
Back in action, but whooee! Muzzle blast and flash! Earthquake!

I inherited Dad's gun.
Found and bought a matching barrel on ebay. It will be as new by next summer.

 

[bockja]

Also, I just checked my Hornady #9 manual. In the Rifle section under 30 M1 Carbine, for Alliant 2400 with a 110 gr RN or FMJ it says min of 10.9 gr and maximum of 12.2 gr. It happens to have a maximum of 14.9gr for W296 and H110 on the following two rows. I would go back and make sure you are reading your manual correctly.

 

[erudne]

W/ 30 cal. Carbine pistol loads start w/ 32-20 pistol data or 38 spl data and work your way-up.
OR:
enter: 30 cal. Carbine pistol reload data in your search engine

 

[Mark W.]

Pistol chambers, Revolver cylinders are not rifle chambers.
The gun must be designed to withstand the expanding pressures at every moment of the process until the bullet exits the muzzle.
Example: 38 special won't survive 38+P or 357mag loads even though the powder will fit in the 38spl case.
Was part of my learning curve. My revolver still looks brand new, but is unservicable, unrepairable because the frame stretched.

Yes but the ONLY factory rounds available for a Handgun chambered in .30 carbine are in fact Carbine loads that duplicate the Military carbine loads.

As to the strength of the cylinder on a Ruger Blackhawk since the cylinder is the same diameter as the Blackhawk with a .357MAG chambering the .30 carbine cylinder is stronger since the chambers are .025" approx. smaller in diameter so have more material around them on all sides.

I been reloading since 1968 I started when I was 11. now 56 still haven't have a squib or a double load and never damaged a firearm with my loads. And that's from modern rifles and pistols all the way back to 100+ year old Winchesters and Remingtons.

 

[Mark W.]

Also, I just checked my Hornady #9 manual. In the Rifle section under 30 M1 Carbine, for Alliant 2400 with a 110 gr RN or FMJ it says min of 10.9 gr and maximum of 12.2 gr. It happens to have a maximum of 14.9gr for W296 and H110 on the following two rows. I would go back and make sure you are reading your manual correctly.

You sir are correct in throwing together my OP I made a mistake. I have edited the OP to reflect the correct info.

 

[usagi]

So why do the reloading manuals so greatly under rate the amount of powder that can be used?
And why does one manual show such a lower allowable Max for the same powder and ball?

different powder lots.

that's why you should always work up a new load and chronograph whenever you change powder lot numbers. it's also why you buy as much powder of the same lot as possible so you don't have to always work up new loads

 

[PBinWA]

A chronograph is almost mandatory for accurate repeatable reloading results. Everything else is pretty much guess work.