.455 converted to .45 Question

The Lyman pistol & revolver reloading guide lists dozens of loads for the ACP & AR and lists their pressures. Easy to compare. AR or ACP, lead bullet or jacketed, if same velocity and bullet weight the pressure is the same.

Factory ACP and AR both shoot 230 grain bullets at about 830fps.
 
The Lyman pistol & revolver reloading guide lists dozens of loads for the ACP & AR and lists their pressures. Easy to compare. AR or ACP, lead bullet or jacketed, if same velocity and bullet weight the pressure is the same.

Factory ACP and AR both shoot 230 grain bullets at about 830fps.

What is really important is finding out what the British considered a proof load for the 455. Once you have that, compare it to the ACP/AR pressure and see how they stand up.

Kevin
 
My question was a ballistic one. The ACP & the AR have the same case capacity, shoot the same weight bullet at the same velocity. The factory loadings have identical ballistics, 230 grain bullets at 830 fps.

If both cartridges shoot a 230 gr .45 bullet at about 830 fps, from the same size case, how can one be safe and other not.
 
You are right a 230 gr 45 ACP should have very close to same pressure as a 230 gr 45 AR using same bullets. Due to case capacity variation, one may take more or less powder than the other to make that velocity/pressure. Also, the gun used to record velocities has some effect.
 
How about just firing .45 Colt in this revolver? That’s what I fire in my Triple Lock, as converted to .45 AR.
 
How about just firing .45 Colt in this revolver? That’s what I fire in my Triple Lock, as converted to .45 AR.

Unless the chambers are reamed deeper a conversion will not chamber a 45 colt case and if 45 colts will chamber in one converted to fire AR cases it have a gross amount of head space unless the colt rounds are actually head spacing on the case mouth , which IMO (I am not humble :)) is a poor practice with a roll crimped case.

An AR rim is .0827 thick and a 45 colt is .060. A .0227 mismatch. Long reach for the firing pin and a the case gets a teal run at the recoil shield if it fires
 
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Unless the chambers are reamed deeper a conversion will not chamber a 45 colt case and if 45 colts will chamber in one converted to fire AR cases it have a gross amount of head space unless the colt rounds are actually head spacing on the case mouth , which IMO (I am not humble :)) is a poor practice with a roll crimped case.

An AR rim is .0827 thick and a 45 colt is .060. A .0227 mismatch. Long reach for the firing pin and a the case gets a teal run at the recoil shield if it fires

IIRC, the recoil shield on mine was shaved.
 
IIRC, the recoil shield on mine was shaved.

Don't mater where the material came off as far as chambering and head space goes. Shaving the recoil shield would however give you lots of stick out on the hammer nose. Shaving the cylinder or recoil shield will not allow chambering a 45 colt with out reaming the chambers deeper. The 45 colt case is 1.285 long and the longest 455 (MKI)is only .886. Plus, if it was shaved for 45AR they had to take off at least .0437 as the 455 has a rim thickness of .039 and the Auto Rim .0837. 45 colts (and all other American revolver cartridges) have a rim thickness of .060. Which gives you the .0237 excess head space if run a 45 colt.

That much head space is huge.

Have you chambered 45 AR in it?

My 455 Triple lock was reamed to 45 colt and recessed .022 so the thicker case head clears. I can still fire 455 ammo in it because the rims are wider (.535") than 45 colt (.512"). If I put in a 45 AR the rim thickness would not allow the cylinder to close.

My 455 2nd model is still completely stock and only chambers 455 ammo.. I could easily make it a dual cylinder gun if I fit a 45 acp cylinder to so it could fire 45 acps, but I already have a 1917 commercial, a Brazilian, 2 325s, and a 3 1/ and a 4" that fire both 45 acp and colt using 45 colt cylinders with the center recessed to hold acps in full moon clips.

5sqvM4P.jpg
 
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Proof load for the 0.455 was ~13,000 psi. If you want to "torture the modified Webley with a full load 0.45ACP" go ahead, but make certain that you are using a remote firing stance! Dave_n
 
My question was a ballistic one. The ACP & the AR have the same case capacity, shoot the same weight bullet at the same velocity. The factory loadings have identical ballistics, 230 grain bullets at 830 fps.

If both cartridges shoot a 230 gr .45 bullet at about 830 fps, from the same size case, how can one be safe and other not.

They cannot, unless both are below ~15,000 PSI.
 
Don't mater where the material came off as far as chambering and head space goes. Shaving the recoil shield would however give you lots of stick out on the hammer nose. Shaving the cylinder or recoil shield will not allow chambering a 45 colt with out reaming the chambers deeper. The 45 colt case is 1.285 long and the longest 455 (MKI)is only .886. Plus, if it was shaved for 45AR they had to take off at least .0437 as the 455 has a rim thickness of .039 and the Auto Rim .0837. 45 colts (and all other American revolver cartridges) have a rim thickness of .060. Which gives you the .0237 excess head space if run a 45 colt.

That much head space is huge.

Have you chambered 45 AR in it?

My 455 Triple lock was reamed to 45 colt and recessed .022 so the thicker case head clears. I can still fire 455 ammo in it because the rims are wider (.535") than 45 colt (.512"). If I put in a 45 AR the rim thickness would not allow the cylinder to close.

My 455 2nd model is still completely stock and only chambers 455 ammo.. I could easily make it a dual cylinder gun if I fit a 45 acp cylinder to so it could fire 45 acps, but I already have a 1917 commercial, a Brazilian, 2 325s, and a 3 1/ and a 4" that fire both 45 acp and colt using 45 colt cylinders with the center recessed to hold acps in full moon clips.

5sqvM4P.jpg

Well, I’ll just have to find mine and see what was done for sure.
 
Could someone post a picture of what the recoil shield looks like before and after shaving? I hace one marked .45 colt but the marking was performed (I believe ) when the gun received it military marks. Thanks from the prairie slave state.
 

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