45 acp Taurus throats??

L

longspurr

New member
I just picked up a Taurus 45 ACP revolver- model 455 and started shooting it. 45 ball worked ok but when I tried WW 45 hollow points I ran into trouble. It seems some of the rounds would seat fully and others have about 1/8 “ sticking out. As I played with my dial chrono looking for the reason it dawned on me to check the cylinder throat diameter. I’m measuring .442” on all cylinders. My Ruger blackhawk measures .449 and from posts on the Ruger forum this is right in the ballpark so I believe my measurement.

The Ruger forum suggests getting a reamer from Brownells and increasing the throat to .452” on the Blackhawks.

My questions:
Would others please measure their Taurus 45 revolver throats so I can get an idea if what I have is common for Taurus. If I try to exchange this gun and the .442 throat is common then I am wasting my time & the dealer’s good will.

If I send it for repair has anyone done this with success? What size throats did you end up with?

If I do the ream Job myself I will void the warranty if there is any question raised. By removing approx. .01 of steel from the throats I think the pressure should go down. Right? Measuring with the dial chrono I’m not getting good measurements of the cylinder wall thickness but it is in the range of .070 - .072 at the throat and .056 - .062 over the cartridge portion of the cylinder. Not exactly confidence inspiring thickness’ when you look at the barrel wall thickness.

Thanks
 
throating

Dear Shooter:
You are a careful shooter!
I'd definately ream that cylinder throat to .452 or even .453. You want the throat on a revolver at bullet dia. or maybe only .001 more! Most 45s' are .4515-.452. the bullet, that is. Even the 45 long colt now is .4515-.452.
I'd also check your seating depth on those rounds.
Harry B. :) You're doing the right thing.
 
First I would be sure that the measurement you are getting is accurate. You might want to try using a hole gauge and micrometer as this should give you a very accurate measurement. If you don't have this equipment and have a local pistolsmith or gunsmith he should have the equipment and be able to check this for you. If this fails check the nearest machine shop they should be able to do this for you.
I'm not saying that your measurements are wrong but .442 cylinder throats seems to be a big difference if you have a normal 45 bore diameter in the barrel.
Regards
Bob Hunter
www.huntercustoms.com
 
Bob
After I read your post I went back and pounded a lead bullet through the cylinder throat. I measured the bullet and came up with .450 on my dial caliper. It is obvious now that my technique for measuring the cylinder throat while the cylinder is still in the gun is flawed. The throat must be the .450 not as I posted above .442.

My original problem is back to square one. I don't know why some factory ammo fully seats in the cylinder and > 50% sticks out about 1/8" so the cylinder will not close. Something about the cylinder must be on the small side of tolerences. The ammo that would not seat in the Taurus seats fine in a Ruger 45 convertable. Back to head scratching unless someone has an idea. Perhaps taking it to someone qualified - gunsmith- is the right idea.
 
longspurr,
Is the ammo the same brand and type? If the ammo has different bullet styles it may be that the ogive of the bullet itself is further forward on the ones that seem to long.
Is all the ammo the same OAL?
You also might want to check and make sure the bullets are seated straight in the case. If not they may have caused a slight bulge in the case making it fit tight in the cylinder.
Also you might want to check the crimp.
Regards
Bob Hunter
www.huntercustoms.com
 
45acp

Dear Shooter:
The gentleman has it I think and, that .450 dia is on the small side.
On 45 autos' I have a "throating" reamer that cuts a leade in the rifling in front of the chamber; this gives room for all the different shaped ogives.
You might look in Brownells and see if they have a reamer for your cylinder - the best fix is to send it to Taurus.
Harry B.
 
Bob & Harry
Thank you for your suggestions.
My original ??!!## was after loading the moon clips with some Winchester 230 JHP Q4243 ammo and not being able to close the cylinder. Since this is a new gun that I just exchanged for a poorly functioning one I assumed this gun also had a problem of some sort.

I went back now and started checking other ammo. Ball ammo worked fine. A box of Fed 165 jhp’s work fine. The first box of Winchester has 13 of the 20 that don’t fit fully into the cylinder. A second box has 8 out of 20 that don’t fit fully.

Measuring found the OAL of the “bad” ammo is 1.21 to 1.214. Checking the bullet diameter just above the case I found .448 - .449”

Measuring “good” ammo OAL is 1.209 to 1.21. Bullet diameter .448

Winchester ball that works fine is OAL 1.266. Bullet diameter .445-.446

The “bad” ammo drops into a Ruger Convertible cylinder. At this point I don’t think I can point a finger at the ammo OR the gun and say it is bad. I think this is just a case of manufacturing tolerances that combined make a problem. Especially for this gun –CCW use- I will just have to be careful & check ammo before I load it up and expect reliability.

If someone made a gun like this - 45 ACP snubby that uses moon clips- within 150% of the price I paid for this I might be interested. As far as I know Taurus has this little nitch all to itself.

Range results; At 15’ eight of ten rounds were one big hole. At 50 ft. 5 shots went into about 3”. Not too bad for a shorty.
 
longspurr,
You are welcome for any help I may have given you. As for the ammo, JHP ammo will have a shorter OAL than ball ammo because of the bullet style. Measure the case mouth to see what the diameter is as this may be the problem area. Also you may want to check the extractor rebate (the area just in front of the rim) and the rim on the ammo that's causing the problems.
Your cylinder may be bored a little on the short side, this would create a head space problem and that might be what's causing the problems with some of the JHP ammo. Again this will go back to the location of the bullets ogive I refered to, as the ogive of the problem ammo may be further forward.
Checking each individual chamber in the cylinder with a head space gauge will tell you if the cylinder is the problem.
Regards
Bob Hunter
www.huntercustoms.com
 
My first thought was one or several of the chambers might be short. Without seeing the handgun in the flesh, my opinion would be speculation. A set of "go, no go" Wilson gage would tell the tale. Check each chamber, as suggested. Even though it may appear that the gun may be at fault, since the ACP headspaces on the case mouth, you might check the case lengths of your ammo.

SAAMI max is .898", min is .888".

Does have all the indications of chambers that are too short....however, I can sometimes go just as fast in the wrong direction as the right direction.... :)
 
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