FWIW, you can rent a chamber reamer for less than half the cost of a new one: https://4drentals.com/product/45-acp/
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FWIW, you can rent a chamber reamer for less than half the cost of a new one: https://4drentals.com/product/45-acp/
When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind. [Lord Kelvin]
This first gun that I'm building will mainly be a range gun, less than 25 yds. For that purpose alone, I'm sure a Sarco or Swenson barrel would serve just fine. It's purpose is more than that though. I want to build a gun. Or two.
My ultimate goal is to build a 5" target model. I am using this first 4.25" model to perfect my techniques before attempting the 5".
Everything is going well so far. My biggest problem is finding parts that I like.
These Kart barrels, which all seem to be chambered and throated alike, reportedly work ok for round nose and flush shoulder semi wadcutters. I would like more freebore though (see my next post).
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But semiwadcutters shouldn't be seated to a flush shoulder. Niemi24s has had a number of posts on this, going back probably a couple or three years. There should be just s small amount of exposed shoulder above the mouth of the case. I've only encountered one pistol where that was a problem (using factory-loaded semiwadcutter ammo), and the gun manufacturer acknowledged the problem and replaced the barrel.
Hawkmoon
On a good day, can hit the broad side of a barn ... from the inside
That looks like a good option if only reaming one barrel, or several within one week's time, but it looks like I may be reaming two of them many months apart. It's cheaper at that point to just buy one. So I ordered a Manson. Brand new, perfectly sharp, and I get to keep it.
I'm perfectly happy with the 0.001" undersize chamber diameter. Or at least I would be until commercial ammo no longer fits. But the freebore appears to be minimal at best. I would like to see more:
Kart_freebore_1.jpg
Thanks for the correction.
I was just trying to describe the bullet on the right (below), as opposed to the one on the left:
bullet_1.jpg
When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind. [Lord Kelvin]
If I'm reading it right, the prints show 0.110".
Also, someone mentions 0.100" here:
https://forum.m1911.org/showthread.p...finish-reaming
The lengths in my barrel photo are not as short as they look. Still not even close to 0.100" though.
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I think you have your terminology a little mixed up. The average 45Auto barrel has a 0.022" freebore as shown below:
That 0.1XY dimension is for the entire throat. And Throat = Freebore + Leade. The 0.450D"D gauge ball is part of the Ordnance measurement method. It's really the only way to measure some of this this stuff. However, a driven slug or chamber casting will do for the throat axial dimensions.
Q: can you see the image?
When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind. [Lord Kelvin]
Last edited by niemi24s; 7th April 2018 at 13:41.
Yes, I can see it.
I had the terms right; my dimension is apparently wrong then, along with my sources.
One dimension is from here, post #6:
https://forum.m1911.org/showthread.p...finish-reaming
...while .100" is considered enough Wil recommends .200" of free bore...
Also used the SAAMI chamber drawing which appears to be the same as in J. K.'s vol II, pg 105.
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Don't let semantics lead you astray and get hung up on definitions. That 0.200" dimension talked about is probably the 0.111" shown in my drawing. If you want to lengthen the area in your barrel between the chamber stop shoulder and the place where the barrel lands are their full height (or not reamed down) you'll need another type of reamer - a throating reamer. Throating reamers are designed to deepen the throat without increasing headspace (by moving the stop shoulder forward).
You're free to do whatever you like with your own barrel but if you think more freebore/leade/throat is going to solve the problems with an undersized chamber - think again.
Bear in mind that the maximum SAAMI case mouth OD is 0.473". That is easily attained with a 0.452" lead bullet in good thick walled brass.
Is there some compelling reason other than the mere mention of a 0.200" freebore that makes you want one?
When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind. [Lord Kelvin]
Last edited by niemi24s; 7th April 2018 at 20:13.
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