.32-20 in .30 carbine Blackhawk

[Acorn]

I bought 200 Starline .32-20 cases to begin shooting in my NM .30 Blackhawk.
I have a question.
I've read the .32-20 brass has to be trimmed.
I've read it's possible to shoot factory .32-20 in a NM.
The .32-20 is .025 longer than .30 carbine.
What happens with the .025 extra length.
Doesn't it interfere with the throat and raise pressure?
If not, why trim?
Apparently I'm missing something.

 

[Johnnu2]

Another good question is:
Since a Ruger 30Carbine barrel is .308", is it safe to shoot .312-.313" (.32-20) bullets out of it...?
Hamilton Bowen Custom Guns is the best place to ask these questions:

+ Bowen Classic Arms + Home

Bowen Classic Arms - Makers of fine custom revolvers for over 30 years

bowenclassicarms.com

J.

 

[Bruce51]

I have fired 327 Federal in a 30 carbine Blackhawk. Just a few moderate loads. So the same bullet diameter.
It works but when checking the forcing cone there was a large build up. This build up was constricting the forcing cone to a much smaller diameter for the bullet .312. or .308 to past through. Sounds like a recipe for a kaboom if more rounds were fired. Just an observation. Will not try it again.

Bruce

 

[GasGuzzler]

I ain't doing it but the only reason I have a mold and .32-20 brass is a family heirloom first gen Colt issued by the State of Texas.

 

[Bruce51]

The rim on 32-20 brass is to thick to allow rotation on an OM Blackhawk.
Bruce

 

[Ale-8(1)]

Yes, but the NM's allow for rotation. The .30 Carbine chamber is 1.290" deep. The .32-20 case is 1.315" overall length, but the rim stops it 0.065" short of going fully into the chamber so only 1.250" of the chamber is used.

 

[Acorn]

Yes, but the NM's allow for rotation. The .30 Carbine chamber is 1.290" deep. The .32-20 case is 1.315" overall length, but the rim stops it 0.065" short of going fully into the chamber so only 1.250" of the chamber is used.

Ahhh, thank you.
So trimming is not necessary?

 

[Ale-8(1)]

Nope . . . but I'll defer to experts.

About the bullet diameter w/respect to the bore size . . . this gets done a lot although it's technically probably inadvisable. I dunno. I'd do it only with lead bullets, never jacketed stuff.

 

[Wyandot Jim]

I shot hand load LEAD 32 Mags out of my Old model 30 carbine no problem.

 

[idsubgun]

Why not buy .30 Carbine brass?

 

[Rat76]

I shot hand load LEAD 32 Mags out of my Old model 30 carbine no problem.

I'd verified that 32-20 won't work in my OM BH30 but it never crossed my mind to try a 32 mag. Fits just fine, now my question is, will a 327 Fed Mag work also?

Having rounds that locate on the rim instead of the case mouth seems to work better.

Edit to add, Post #3 answered my 327 question,

 

[CHEVYINLINE6]

Back in the late 1960's a friend asked me to pick up some 32-20 ammo for him while I was at the local sporting goods store. If I remember right, my friend has a Colt Police Positive double action revolver. While at the sporting goods store, the saleman asked me which 32-20 ammo I wanted. The salesman explained to me that there were two different loads available in 32-20. The load for revolvers and a more powerful load for rifles. He said it would not be a good idea to shoot that rifle ammo in the old Colt that my friend had.

CHEVYINLINE6.

 

[Acorn]

Why not buy .30 Carbine brass?

.30 carbine headspace's on the case mouth.
.32-20 on headspace's on the rim.
I understand the .30 carbine is sensitive to overall case length.
Trim too short inconsistent ignition. Too long it can tie the gun up.
.32-20 brass once fired basically become a rimmed .30 carbine.

 

[Bruce51]

Well yes and no. I have some way to short 30 carbine brass. I also have a really short firing pin.
They all go bang everytime. In fact I load the short cases only for the BH.
Once again if you want to shoot .32 caliber bullets in a .308 bore check the barrel forcing cone to be sure there is not a build up. Also accuracy may be an issue.

Bruce

 

[NikA]

Yes, but the NM's allow for rotation. The .30 Carbine chamber is 1.290" deep. The .32-20 case is 1.315" overall length, but the rim stops it 0.065" short of going fully into the chamber so only 1.250" of the chamber is used.

This explanation is close but incorrect.

The real answer is that the 1.315" .32-20 case length is the max length, and most brass will be sufficiently shorter to allow use in the .30 carbine chamber without trimming. The .30 carbine chamber won't be 1.290" deep unless the entire case head is inside the chamber, as I understand may be the case on OM guns, but cannot be the case on NM guns with clearance to allow use of .32-20 brass.

In any case, I walked out to the reloading room and measured a couple new Starline .32-20 brass and came up with 1.285-1.290", so I'd say this is possible with minimal or no trimming.

 

[Ale-8(1)]

.32-20 brass once fired basically become a rimmed .30 carbine.

That's how I see it.

 

[idsubgun]

.30 carbine headspace's on the case mouth.
.32-20 on headspace's on the rim.
I understand the .30 carbine is sensitive to overall case length.
Trim too short inconsistent ignition. Too long it can tie the gun up.
.32-20 brass once fired basically become a rimmed .30 carbine.

How thick is the .32-20's rim? I just measured my OM BH in ,30 Carbine and it has only about .022" clearance between the frame and cylinder. Are the NM's that much wider?

 

[Acorn]

How thick is the .32-20's rim? I just measured my OM BH in ,30 Carbine and it has only about .022" clearance between the frame and cylinder. Are the NM's that much wider?

.065.
Only NMs can chamber and rotate.

 

[Watertender]

Back in the late 1960's a friend asked me to pick up some 32-20 ammo for him while I was at the local sporting goods store. If I remember right, my friend has a Colt Police Positive double action revolver. While at the sporting goods store, the saleman asked me which 32-20 ammo I wanted. The salesman explained to me that there were two different loads available in 32-20. The load for revolvers and a more powerful load for rifles. He said it would not be a good idea to shoot that rifle ammo in the old Colt that my friend had.

CHEVYINLINE6.

Interesting. I knew that there were 2 different loads for the 44-40. It does make sense that there would be loads for the 32-20 and 38-40 as well

 

[GasGuzzler]

I don't think I'd say there's "two loads" for 32-20 WIN. I would say to keep the pressure in the original black powder range for an old Colt.