45 acp won't chamber (throat/leade is renamed already)

[JedYonkers]

I am having an using with a new "match barrel"
Chambers FMJ however my cast loads at .473 only go about half way into the chamber. My factory colt barrel and Springfield plunksnot problem I am guessing the chamber is about .475ish on the colt. Would a finish reamer open the chamber up or would it only do SAAMI minimum? Can I lap or hone it ? Or is a custom reamer needed? Again the throat has been reamed already with a mason throater. Sized brass drops in fine , tried 4 brands of brass with varying wall thickness and same problem, I don't want to have to size my boolits to less than .452.

[Went2kck]

resize the bullet it will be easier.

[DougGuy]

Manson makes I think A, B, and C finish reamers which cut different sizes, give Dave or Clyde a call and discuss it with them. I also have one or two finishers you could send it this way if you like.

You should be able to get a .452" taper crimped to .472" to plunk. What are you using to measure with? Also if you have a match barrel it probably hasn't had the headspace set either. Lots of those barrels are short chambered at .899" or so, I set them at .902" ~ .906" when they come through the shop.

[BNE]

Dougguy beat me to it, but he does good work. My Kimber barrel feeds all of my loads now. Great accuracy also.

[JedYonkers]

I can give dave a call or stop by, it's only a 20 minute drive for me, I might as well get some head space gauges as well.

[243winxb]

Apply more taper crimp.

[gnostic]

^^^^What 243winxb said...^^^^ I use a taper crimp to take my 45acp's down to .470 at the case mouth and they shoot great in my S&W, Colt and Detonics. I've probably shot 100K round in !911's in 50 years and never had an issue....

[JedYonkers]

https://ibb.co/gFqNLHL

https://ibb.co/B6CMJ3n

Sized cases measure .472 and chamber fine.

[Pressman]

Sounds like a sizing die issue. What brand of dies are you using? Will a sized, empty case fully chamber?

[DougGuy]

Here: https://ibb.co/B6CMJ3n is part of the problem. First off, calipers are not adequate enough for precise measurements, and measuring a case like that I have never seen done, you want to use a micrometer and measure across the cartridge at the case mouth on a 90 degree axis, measure diameter, turn 90 degrees measure again. You should not have issues if this measurement is .472" or less but do use a micrometer.

[Larry Gibson]

I have the same problem with on of my M1911s (a Para 14 with match chamber) which chambers milsurp, factory and jacketed reloads perfectly. They all use .451 bullets. It also chambers any I load with .451 bullets. With .452 bullets it does not reliably chamber 2 -3 out of every mag. The slide stops just short of going fully into battery.

Seems you paid for the match chamber so why mess it up? I solved my problem by sizing all my 45 cast bullets at .451 now. I found no decrease in accuracy with my other .45s and do not get any leading in any of them. However, I first solved the problem for the Para 14 by running the loaded ammo (with .452 bullets) through a Lee FCD. That sized down the odd oversized case/bullet combination. Since sizing to .451 now everything I load for 45 ACP on my Dillon SDB feeds 100% in all my M1911s and also shoots just fine in my M1917 S&W, my conversion cylinder for my SAA and in my Contender. Oh, in my Rhineland M98 conversion to 45 ACP also.

[Winger Ed.]

Doing any surgery on that match chamber would be my last resort.

[JedYonkers]

Went back and used my micrometer and came up with an average of .4734. Recrimped several already loaded rounds and got most of them to go all the way in. Seems like the federal and CBC brass are just too thick to make it work. I was just hoping to be able to open the chamber up .001 so don't have to sort brass.

[Brassduck]

I would make the ammo fit the barrel. had the same problem, used a 308 sizing die to taper the case. Good Luck

[243winxb]

Different brands of brass need the taper crimp die set different.

The case length is another factor. Different trim length, different taper crimp.

This is why i keep in rotation 500 Starline Brass. Same amount of loadings/firings. No die adjustments.

Bullets larger then .452" can be a problem.

[Martin Luber]

I assume the measurements you refer to are the mouth or crimp diameters. 0.470 is the standard crimp that gives a continuous straight wall.

I would bet you can feel a ridge on your loads? No bueno

[DougGuy]

I assume the measurements you refer to are the mouth or crimp diameters. 0.470 is the standard crimp that gives a continuous straight wall.

I would bet you can feel a ridge on your loads? No bueno

If he as brass that's .010" crimping as you suggest would have the boolit swaged to .450" inside the case. MUCHO no bueno!

Crimping to .472" will let the rounds plunk easily and still have a .452" boolit in the case. Muy Bueno!

[Martin Luber]

feeling a ridge at the mouth means there is no crimp

[wv109323]

My Kart barrel needs .470" taper crimp to chamber a round reliably.
Check your headspace with the longest brass you have.

[Green Frog]

OK, every time I see this thread my Froggie brain wanders off to ask, “what is the new name of the throat/leade, and what was wrong with the old name?” You are aware of the EDIT feature, aren’t you? I’m a retired school teacher (Science, not English) so I’m certainly used to seeing misspellings, but I’m also conscious of the distraction of glaring typos. Rant over, carry on! :coffeecom

Froggie