Throating 45 auto

My Ballaster-Molina 45 has always give me problems with cast. Originally I sized to 452 because that's the only 45 sizer I had. The gun would only return to battery if the boolit was seated so deep in the case that the ogive was right at the case mouth. Today I got my new 451 sizer die, ran a handful through it and started loading. First one I set OAL to 1.250 and tried to chamber it. No go!
It appears that a boolit could be no bigger than 450 at the mouth of the case. When I get it deep enough to chamber the rifling marks go all the way to the case mouth.

My question is can I throat this rifling out to give me .020/.030 of freebore without messing up my head space or am I better off to try to find a different mold design. My primary mold for ACP is the Lee 452-228 1R. Tonight I sized some 452-424 HP weighing 240 grs and could get them to chamber with about .015 of the first driving band outside the case with an OAL 1.240. It got dark on me so can't test run them until morning.

Test ran the 452-424 HP this morning, function was flawless but 4 of the 14 shots keyholed. Is this boolit too long to stabilize?

FWIW,
I just ordered a 45 Pistol throater from Dave Mason reamers and throated my gold cup for cast, because I was having same problems.
The throater is ground to cut .001 over nominal bullet diameter (this seems the same with other brands I checked, but only Mason had them in stock and available right away), so it throats at .452" and cuts a nice ramp into the rifling.
It eliminated sticking SOME boolits into the rifling, but my boolits sized .4525 outside the case still "sticks" up on the throat.
It's WAY better than it was (finger nail instead of screwdriver to remove) but bullets do "stick" when fully chambered and dont "free float" like smaller .451 or jacketed ones do.

I'm still playing with this and may order a smaller .451-.452 sizer to try, but if I had to do it again, I'd just try to find a reamer ground to ramp up from a .453" throat.

Cheers, YV

I use cast 200-gr SWC in my match 1911 and had the chamber reamed very slightly (the 'smith used a hand reamer) so that I wouldn't have problems with cast SWC. Quite a few thousand rounds later, I haven't had any problems related to cast.

I do have to make sure to seat the bullets out enough that the tip enters the chamber far enough so that when it hits the top, it slides into position. When I loaded them too short, the tip often would hit the top of the chamber and just freeze there.

My *opinion* is that 240 grains is too heavy/long for the standard twist used with.45ACP. I can't remember where I read it, but the book/article said the .45ACP originally was loaded with either a 200- or a 210-grain bullet.

Richard

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Originally Posted by RG1911

I use cast 200-gr SWC in my match 1911 and had the chamber reamed very slightly (the 'smith used a hand reamer) so that I wouldn't have problems with cast SWC. Quite a few thousand rounds later, I haven't had any problems related to cast.

I do have to make sure to seat the bullets out enough that the tip enters the chamber far enough so that when it hits the top, it slides into position. When I loaded them too short, the tip often would hit the top of the chamber and just freeze there.

My *opinion* is that 240 grains is too heavy/long for the standard twist used with.45ACP. I can't remember where I read it, but the book/article said the .45ACP originally was loaded with either a 200- or a 210-grain bullet.

Richard

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45 colt usually uses 1/16 and people run bullets over 300 grains with nobody ever reports keyholing due to insufficient twist.

This chart shows .457 bullets in 1/16 twist being good up to 1.96 inch long bullet. That is a BULLET nearly a half inch longer than a 45 acp CARTRIDGE :-) so would I think there is no twist issue with any bullet we can load and fire in a 45 acp pistol.

http://www.montanabulletworks.com/page11.html

Interesting about throating the barrel... May need to find a smith to do that on my 1911 Kart barrel... Running into the same issues + a ton of leading.... Makes sense if the leade is too sharp/short...

Thanks